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21LS-90N

SERVICE MANUAL
SE0021LS90N00
Issued: 1st Mar. 2004

AK- 44 CHASSIS
PAL B/G / SECAM L/L', B/G, D/K SYSTEM COLOUR TELEVISION

MODEL

21LS-90NES

In the interests of user safety (required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used.

In order to service the model 21LS-90N, refer to the AK-44 Chassis Service Manual (SE00AK44CHA00).

CONTENTS
ELECTRICAL SPECIFICATIONS ........................................................................................ 3 IMPORTANT SERVICING NOTES ...................................................................................... 4 CONTROLS & TERMINALS ................................................................................................ 5 PRINTED WIRING BOARD LAYOUT ................................................................................. 6 PARTS LISTING ................................................................................................................... 7 HOW TO UPDATE THE TECHNICAL INFORMATION ...................................................... 11

SHARP CORPORATION
1

This document has been published to be used for after sales service only.

21LS-90N

SERVICE MANUAL UPDATE LOG SHEET
Technical Report No. Technical Bulletin No. Cause / Solution Part No. Page No. Application Data /Serial No.

Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc. If only part number changes are required, just change part number directly the part number in the Parts Listing Section. If you need more information, please refer to the Technical Report (Bulletin).

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21LS-90N

ELECTRICAL SPECIFICATIONS
·Power Input .................... 220V-240 Volts AC 50 Hz ·Power Consumption Normal Operation (Method IEC60107) .............. 64 W Stand-by Operation .......................................... < 3 W ·Audio Power Output Rating (MPO) / Impedance Internal Left Speaker ................................. 4 W, 16 Internal Right Speaker ............................... 4 W, 16 ·Speakers Speaker elliptic (2 pcs) .......................... 50 x 120 mm ·Convergence (Maximum Misconvergence)
mm 21"

·Picture Intermediate frequency L' ................................................ 33.9MHz L, B/G, D/K .............................. 38.9MHz ·Sound Carrier Trap L' ................................................ 40.4MHz L, D/K ......................................... 32.4MHz B/G ............................................ 33.4MHz ·Adjacent Sound Carrier Trap L' ................................................ 32.4MHz L, D/K, B/G ................................ 40.4MHz ·Adjacent Picture Carrier Trap L' ................................................ 41.9MHz L, D/K ...................................... 30.9MHz B/G ............................................ 31.9MHz ·Aerial Input Impedance VHF/UHF ................. 75 ohm Unbalanced ·Tuning Ranges ..... 48.25MHz thru 855.25 MHz VHF: S1 - S41 CH (Hiperband) E2 - E12 / F2 - F10 UHF: E21 - E69

AREA A BC DE FGHJ KLMN F'G'H'J' STUV

0.3 1.0 1.0 1.3 1.2 1.2 1.1

·White Level Apply the rated voltage at the rated frequency to the TV set, while it is receiving full white pattern RF signal of 60 dB/µV from its RF input via the pattern generator. Turn all picture controls to maximum value. Measure the colour temperatures at the center of the screen by using the colour analyzer. X=0.290 ± 0.015 Y=0.300 ± 0.015

Specifications are subject to change without prior notice.

MODEL DESTINATION (Operation Manual Languages)
21LS-90NES: Español, Português.

WARNING The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug and power receptacle, when servicing this chassis. To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to qualified service personnel.

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21LS-90N

IMPORTANT SERVICING NOTES
Only qualified service personnel are allowed to carry out maintenance and repair of this receiver.

Servicing of High Voltage System and CRT
It is important that the static charge is removed from the high voltage system when carrying out work on the receiver. This can be achieved by connecting a 10K resistor (with a suitably insulated lead) from the CRT cavity connector to the CRT ground tag. This must be carried out with the AC supply disconnected from the receiver. Note the following: · The CRT in this receiver employs Integral Implosion Protection. · If the CRT has to be changed it MUST be replaced with the correct type for continued safe working. · DO NOT lift the CRT by its neck. · When handing the CRT, ensure that shatterproof goggles are worn. · Ensure that the CRT is discharge before handling.

X-Ray
This receiver is designed to keep any x-ray emission to an absolute minimum. Some fault conditions and servicing procedures may produce potentially hazardous x-ray radiation levels. This is a problem when in close proximity to the receiver for long periods of time. To reduce any risks associated with this, please observe the following precautions: 1. When undertaking any servicing on this chassis, DO NOT increase the EHT to more than 29.5 KV, (at a instantaneous beam current of 1150 µA). 2. Ensure that during normal operation the EHT does not exceed 26.2 KV (at a beam current of 1150 µA). This level has been preset in the factory. Always check that this level has not been exceeded after carrying out any repair on the receiver. 3. DO NOT replace the CRT with any other type than that specified in the parts listing as this may cause excessive x-ray radiation.

Before returning the receiver to the customer
In addition to the above checks, the following should also be carried out before returning the receiver to the customer. 1. Inspect all the leads to ensure that they are dressed correctly and that they are not obstructed or pinched by any other parts. 2. Ensure that all protective devices are in good condition. These will include nonmetallic control knobs, insulating fish papers, cabinets backs, compartment covers or shields, mechanical insulators, etc.

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21LS-90N

CONTROLS & TERMINALS
Speakers (left + right) = Power On / Off = Volume -/+ CH = Program -/+

MENU = Menu

MENU

REMOTE CONTROL
1 2 3 4 5 6 7 8 9 10 11 12
EXT

= Stand By = Cursor Up = Cursor Right OK = OK = Info (Program Menu) 0 - 9 = Direct Program -/-- = Double Digit = Wide mode button P/CH+ = Program + + = Volume + = TV / Quit Menu

= EXT button (SCART, F- AV, RGB) 13 Yellow = Feature Menu 14 Blue = Installation Menu

15 = Hold 16 = Update 17 = Index Page 18 = Reveal 19 = Expand 20 = Mix 21 = Teletext 22 = Time 23 Red = Sound Menu 24 Green = Picture Menu 25 = Mute 26 I-II = Mono/Stereo - Dual I-II 27 = - Volume 28 - P/CH = -Program 29 = Flash back button 30 M = Menu 31 = Cursor Down = Cursor Left 32

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21LS-90N

CHASSIS LAYOUT
Mother Unit

CRT Unit

6

21LS-90N

PARTS LISTING
REPLACEMENT PARTS
Replacement parts which have special safety characteristics are identified in this manual. Electrical components having such features are identified by in the Replacement Parts Listing. The use of a substitute replacement part which does not have the same safety characteristics as the factory recommended is not permitted. Replacement parts not shown in this service manual may create shock fire, or other hazards.

HOW TO ORDER REPLACEMENT PARTS
To have your order completed promptly and correctly please supply the following information. 1. MODEL NUMBER 2. REF. NO. 3. PART NO. (*) 4. DESCRIPTION 5. CODE 6. QUANTITY (*) When ordering any part, a "V" should be added before the Part No.
(*)

REF No. D813 D837 D838 D889 D890 D893 D894 D900 D901 D902 D903 D904 D905 D906 X100 X401 X402 X403 X501 X700 L101 L110 L111 L112 L113 L114 L201 L210 L211 L401 L402 L403 L404 L406 L407 L601 L603 L700 L701 L702 L703 L704 L802 L803 L805 L806 L807 Z401 Z402 Z404

PARTS 30001329 30001329 30001329 30001384 30001329 30001318 30001318 30001318 30001318 30001318 30001344 30001349 30001349 30001349 30002852 30001749 30015592 30000074 30002851 30001756 30013412 30013412 30013412 30013412 30013412 30013412 30001979 30001971 30001971 30001971 30001992 30001971 30001990 30001971 30002002 30001990 30002149 30001971 30001971 30001996 30001979 30001979 30001971 30001984 30001971 30001971 30001992

DESCRIPTION DIODE 1N4007 1A/1000V 30A DIODE 1N4007 1A/1000V 30A DIODE 1N4007 1A/1000V 30A TR MCR22-6 DIODE 1N4007 1A/1000V 30A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE ZENER 6.2V 1/2W DIODE ZENER 11V DIODE ZENER 11V DIODE ZENER 11V PACKAGED CIRCUITS XTAL REZ 455KHZ XTAL 4.433619 MHZ (AK15) XTAL 3.579545 (WO/LOAD CAP) CAP MKT 100NF 63V J XTAL 4MHZ L.C=30PF XTAL 18.432MHZ COILS FERRITE BEAD (0805) MMZ2012Y152B FERRITE BEAD (0805) MMZ2012Y152B FERRITE BEAD (0805) MMZ2012Y152B FERRITE BEAD (0805) MMZ2012Y152B FERRITE BEAD (0805) MMZ2012Y152B FERRITE BEAD (0805) MMZ2012Y152B FIXED COIL 1UH Q45 M-A FERRITE BEAT (805) BLM21A601S FERRITE BEAT (805) BLM21A601S FERRITE BEAT (805) BLM21A601S FIXED COIL 10UH Q65 K-A FERRITE BEAT (805) BLM21A601S FIXED COIL 6.8UH Q75 K FERRITE BEAT (805) BLM21A601S FIXED COIL 47UH Q60 K FIXED COIL 6.8UH Q75 K LINEARITY COIL 50UH (06-06A) FERRITE BEAT (805) BLM21A601S FERRITE BEAT (805) BLM21A601S FIXED COIL 22UH Q40 K FIXED COIL 1UH Q45 M-A FIXED COIL 1UH Q45 M-A FERRITE BEAT (805) BLM21A601S FIXED COIL 2.2UH Q55 M-AX FERRITE BEAT (805) BLM21A601S FERRITE BEAT (805) BLM21A601S FIXED COIL 10UH Q65 K-A

SN CODE AA AA AA AB AA AA AA AA AA AA AA AA AA AA AA AC AB AA AC AE AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AE AA AA AA AA AA AA AA AA AA AA AG AF AB AT AC AF AA AA AA AA

EX CODE AB AB AB AG AB AB AB AB AB AB AB AB AB AB AD AK AG AC AH AP AA AA AA AA AA AA AB AD AD AD AB AD AB AD AB AB AN AD AD AB AB AB AD AB AD AD AB AR AR AF BE AH AQ AB AB AB AB

REF No. . .

PARTS 30002749 30028645

DESCRIPTION PICTURE TUBE 21" CPT TUBE SAFE 21" DEG COIL&EARTH CB. SAFE WO/UL SHARP TUNER TUNER WSP (PLL) 38.9 MK2 - BATCH INTEGRATED CIRCUITS IC HT48RA0A OTP IC TL431 IC TDA7266 IC STV2248H (SHRINK56) PREAMPLIFIER TFMS1380 IC TDA8174AW IC MSP3410G SDIP64 IC SMPS MC44608 DIP8 IC SAFE OPTOCOUPLER TCET1102G IC LM7808 IC 7805 (1A) IC 78L05 TO-92 (100mA) TRANSISTORS TR BC337 TR POWER STX112-AP TR BC548B DIODES LED INFRARED IR333 DIODE ZENER 33V UZT 33B DIODE 1N4148 0.15A/100V 0.5A DIODE 1N4148 0.15A/100V 0.5A DIODE 1N4148 0.15A/100V 0.5A LED RED/GREEN LTL293SJ DIODE 1N4007 1A/1000V 30A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE BA159 1A/800V 20A DIODE ZENER 3.6V ZPD DIODE BA159 1A/800V 20A DIODE ZENER 8.2V DIODE BA159 1A/800V 20A DIODE BYD33D 1A/200V 20A DIODE BA159 1A/800V 20A DIODE BYD33D 1A/200V 20A DIODE BYD33D 1A/200V 20A DIODE UF5407 3A/800V 150A DIODE 1N4007 1A/1000V 30A DIODE 1N4007 1A/1000V 30A

SN CODE BQ AG AR AF AC AF AR AD AD AS AF AA AC AB AA AA AA AA AA AB AA AA AA AC AA AA AA AA AA AA AA AA AA AA AA AA AA AB AA AA

EX CODE CG AS BC AR AH AR BC AM AN BD AQ AE AH AF AE AC AE AC AC AF AB AB AB AH AB AB AB AB AB AB AB AB AB AE AB AE AE AF AB AB

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TU201 30009637 IC101 IC118 IC301 IC403 IC502 IC600 IC700 IC800 IC801 IC803 IC804 IC806 Q100 Q601 Q804 D100 D106 D407 D505 D506 D509 D602 D608 D609 D610 D614 D701 D800 D801 D802 D803 D804 D805 D806 D808 D809 D811 30018063 30001506 30011824 30026922 30001669 30015306 30013658 30011968 30015087 30001500 30001622 30014346 30001453 30013656 30001454 30002733 30001377 30001284 30001284 30001284 30001279 30001329 30001318 30001318 30001318 30001318 30001369 30001318 30001347 30001318 30001315 30001318 30001315 30001315 30007681 30001329 30001329

CERAMIC FILTERS 30012545 FILTER SAW K9656M 30014261 FILTER SAW K3958M 30001724 FILTER SER TRAP TPS 5.5MHZ

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TRANSFORMERS TR601 30017788 TRF FBT SAFE 90ø (AK30,AK36 LAYER TYPE) TR801 30002100 LINE FILTER SAFE 2*27MH TR802 30027706 TRF SMPS AK44 90° (170-270V) Audio=12V C100 C201 C205 C300 30000352 30000400 30000371 30000400 CAPACITORS CAP EL 100UF 16V M CAP EL 47UF 50V M CAP EL 22UF 50V M CAP EL 47UF 50V M

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21LS-90N

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REF No. C302 C305 C404 C409 C410 C411 C413 C416 C417 C419 C420 C422 C423 C424 C431 C433 C436 C440 C443 C444 C446 C460 C502 C513 C519 C531 C536 C541 C542 C543 C603 C604 C608 C610 C611 C613 C615 C616 C618 C619 C624 C627 C628 C631 C632 C633 C634 C635 C636 C641 C643 C644 C645 C705 C706 C712 C720 C724 C730 C733 C734 C736 C737 C738 C801 C802

PARTS 30000092 30000092 30000225 30000345 30000384 30000345 30000362 30000362 30000362 30000413 30000100 30000400 30000400 30000345 30000362 30000345 30000100 30000074 30000362 30000384 30000345 30000345 30000396 30000371 30000352 30000384 30000074 30000100 30000205 30000205 30000384 30000345 30000107 30000355 30000092 30000078 30000359 30000352 30007100 30000131 30000350 30000154 30018380 30000410 30000100 30016085 30000409 30000100 30000387 30000345 30000116 30000362 30000352 30000345 30000345 30000345 30000345 30000345 30000393 30000345 30000345 30000345 30000371 30000371 30000094 30000094

DESCRIPTION CAP MKT 220NF 63V J CAP MKT 220NF 63V J CAP CER 220PF 50V J SL CAP EL 10UF 50V M CAP EL 2.2UF 50V M CAP EL 10UF 50V M CAP EL 1UF 50V M CAP EL 1UF 50V M CAP EL 1UF 50V M CAP EL 4.7UF 50V M CAP MKT 330NF 63V J CAP EL 47UF 50V M CAP EL 47UF 50V M CAP EL 10UF 50V M CAP EL 1UF 50V M CAP EL 10UF 50V M CAP MKT 470NF 63V J CAP MKT 100NF 63V J CAP EL 1UF 50V M CAP EL 2.2UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 47UF 16V M CAP EL 22UF 50V M CAP EL 100UF 16V M CAP EL 2.2UF 50V M CAP MKT 100NF 63V J CAP MKT 470NF 63V J CAP CER 150PF 50V J SL CAP CER 150PF 50V J SL CAP EL 2.2UF 50V M CAP EL 10UF 50V M CAP MKT 47NF 250V J CAP EL 100UF 50V M CAP MKT 220NF 63V J CAP MKT 1UF 100V M CAP EL 1000UF 16V M CAP EL 100UF 16V M CAP MKP SAFE 10NF 1600V %3.5 CAP MKP SAFE 100NF 250V J CAP EL 10UF 250V M CAP MKP SAFE 390NF 250V J CAP EL 3.3UF 160V M 105° CAP EL 470UF 50V M CAP MKT 330NF 63V J CAP EL 10UF 63V 105° CAP EL 470UF 25V M CAP MKT 330NF 63V J CAP EL 33UF 50V M CAP EL 10UF 50V M CAP MKT 68NF 63V J CAP EL 1UF 50V M CAP EL 100UF 16V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 3.3UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 10UF 50V M CAP EL 22UF 50V M CAP EL 22UF 50V M CAP MKT SAFE 220NF 275V M AC CAP MKT SAFE 220NF 275V M AC

SN CODE AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AB AA AA AA AA AA AB AA AB AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA

EX CODE AD AD AB AB AB AB AB AB AB AB AD AB AB AB AB AB AD AC AB AB AB AB AB AB AB AB AC AD AB AB AB AB AD AB AD AF AC AB AE AB AD AG AB AF AD AB AD AD AB AB AC AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB

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REF No. C803 C805 C806 C808 C809 C810 C811 C813 C816 C817 C822 C824 C827 C828 C829 C830 C832 C833 C834 C836 C838 C839 C840 C843 C848 C849 C850 C855 C858 C862 C864 C907 C908 C912 R105 R127 R204 R206 R301 R302 R407 R410 R420 R424 R428 R437 R438 R442 R450 R469 R507 R508 R510 R513 R514 R518 R525 R527 R534 R535 R536 R546 R559 R562

PARTS 30000433 30018085 30000433 30000295 30000420 30000387 30000161 30000295 30000440 30000198 30007308 30009208 30000411 30000295 30000359 30000382 30000295 30000407 30000295 30000431 30000352 30000352 30000352 30000431 30000352 30000352 30000352 30000407 30007308 30000367 30000440 30000434 30000415 30000075 30000792 30000459 30000459 30000459 30000471 30000471 30000590 30000590 30000466 30000712 30000792 30000466 30000466 30000466 30000712 30000670 30000466 30000622 30000737 30000459 30000459 30000471 30000583 30000718 30000526 30000718 30000471 30000560 30000470 30000471

DESCRIPTION CAP CER 1NF 1KV M B CAP VAR SAFE 510V K MFCN14D511 CAP CER 1NF 1KV M B CAP CER 100NF 50V Z F CAP EL 150UF 400V M CAP EL 33UF 50V M CAP MKP SAFE 47NF 630V J CAP CER 100NF 50V Z F CAP CER SAFE 2.2NF 4KV M CAP CER 120PF 500V J SL CAP CER 220PF 1KV K (PULSE) CAP CER 470PF 1KV K (PULSE) CAP EL 4700UF 16V M CAP CER 100NF 50V Z F CAP EL 1000UF 16V M CAP EL 2200UF 16V M CAP CER 100NF 50V Z F CAP EL 470UF 16V M CAP CER 100NF 50V Z F CAP CER 100PF 1KV M CAP EL 100UF 16V M CAP EL 100UF 16V M CAP EL 100UF 16V M CAP CER 100PF 1KV M CAP EL 100UF 16V M CAP EL 100UF 16V M CAP EL 100UF 16V M CAP EL 470UF 16V M CAP CER 220PF 1KV K (PULSE) CAP EL 1UF 250V M CAP CER SAFE 2.2NF 4KV M CAP CER 1NF 2KV K B CAP EL 4.7UF 250V M CAP MKT 100NF 250V K (DC) RESISTORS RES CF 1/4W 75R J RES CF 1/4W 100R J RES CF 1/4W 100R J RES CF 1/4W 100R J RES CF 1/4W 10K J RES CF 1/4W 10K J RES CF 1/4W 2.2K J RES CF 1/4W 2.2K J RES CF 1/4W 1K J RES CF 1/4W 470R J RES CF 1/4W 75R J RES CF 1/4W 1K J RES CF 1/4W 1K J RES CF 1/4W 1K J RES CF 1/4W 470R J RES CF 1/4W 330K J RES CF 1/4W 1K J RES CF 1/4W 270R J RES CF 1/4W 5.1K J RES CF 1/4W 100R J RES CF 1/4W 100R J RES CF 1/4W 10K J RES CF 1/4W 220R J RES CF 1/4W 4.7K J RES CF 1/4W 1.5K J RES CF 1/4W 4.7K J RES CF 1/4W 10K J RES CF 1/4W 1.8K J RES CF 1/2W 10K J RES CF 1/4W 10K J

SN CODE AA AA AA AA AF AA AB AA AA AA AA AA AC AA AA AB AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA

EX CODE AB AD AB AB AQ AB AE AB AC AB AD AC AH AB AC AF AB AC AB AC AB AB AB AC AB AB AB AC AD AB AC AB AC AD AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AB AA AB

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21LS-90N

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REF No. R601 R602 R605 R623 R625 R627 R628 R630 R631 R633 R637 R638 R639 R645 R646 R647 R648 R649 R650 R654 R655 R658 R659 R662 R663 R701 R703 R705 R801 R804 R805 R806 R807 R810 R811 R813 R815 R817 R818 R819 R821 R828 R829 R836 R900 R901 R902 R903 R904 R905 R906 R919

PARTS 30000477 30000513 30000477 30000607 30000900 30000910 30000650 30000828 30000885 30000706 30000621 30000589 30000718 30001126 30000500 30000466 30001215 30000801 30000744 30000705 30000705 30001077 30001123 30000712 30000459 30000459 30000459 30000459 30000982 30000504 30000843 30000982 30001130 30001257 30000594 30000718 30000452 30001037 30000925 30000810 30000470 30001265 30000718 30001224 30006712 30006712 30006712 30000886 30000886 30000886 30000525 30001213

DESCRIPTION RES CF 1/4W 100K J RES CF 1/4W 130K J RES CF 1/4W 100K J RES CF 1/4W 2.2R J RES MF 1/4W 1.8K J RES MF 1/2W 1.8R G RES CF 1/4W 33R J RES CF 1/4W 8.2M J RES MF 1/4W 1.5K J RES CF 1/4W 47R J RES CF 1/2W 270R J RES CF 1/2W 2.2K J RES CF 1/4W 4.7K J RES MO 3W 2.2K J RES CF 1/4W 12K J RES CF 1/4W 1K J RES FUSE SAFE 1W 1R J RES CF 1/4W 7.5K J RES CF 1/4W 560R J RES CF 1/2W 47R J RES CF 1/2W 47R J RES MO 2W 10R J RES MO 2W 220R J RES CF 1/4W 470R J RES CF 1/4W 100R J RES CF 1/4W 100R J RES CF 1/4W 100R J RES CF 1/4W 100R J RES MF 1/4W 4.7K J RES CF 1/4W 120K J RES MF 1/4W 10R J RES MF 1/4W 4.7K J RES MO 1/2W 0.22R J RES MG SAFE 1/2W 4.7M J RES CF 1/4W 22K J RES CF 1/4W 4.7K J RES CF 1/4W 10R J RES MF 1/4W 99K F RES MF 1/4W 2.2K F RES CF 1/4W 820R J RES CF 1/2W 10K J NTC MONITOR 10R/3A SCK-103 RES CF 1/4W 4.7K J RES FUSE SAFE 1/2W 0.22R J FERRITE BEAD 3.5X4.7X0.8 FERRITE BEAD 3.5X4.7X0.9 FERRITE BEAD 3.5X4.7X0.10 RES MF 1/4W 1.5K F RES MF 1/4W 1.5K F RES MF 1/4W 1.5K F RES CF 1/2W 1.5K J RES FUSE 1/4W 1R J MISCELLANEOUS PARTS CABLE ASSY.4/45 (HRZ&VER) IMPROVED NEW CRT B.ASSY.TP44-RF/SF (AK44) CRT B.ASSY.TP44-OTO RF/SF (AK44) CHS.ASSY.44-531B2111312229 IC 24C08 U00315210210121102 SPK.AS.2162 SHARP STR (AK44) SPK.AS.2162 SHARP (R) (AK44) SPK.AS.2162 SHARP (L) (AK44) POWER CORD ASSY.(2.4MT W/FTZ)(AK44SHARP) PR.IC.36/44-SHARP 36_44_A17 TR MTP6N60E (PLASTIC) TR BU808DFI

SN CODE AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA AA

EX CODE AB AB AB AB AB AB AB AB AB AB AB AA AB AB AB AB AC AA AB AB AB AC AC AB AB AB AB AB AA AB AA AA AB AD AB AB AB AB AB AB AA AB AB AB AB AB AB AB AB AB AB AA

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REF No. . . . . . . . . . . . . . . . F801 PL101 PL301 PL302 PL405 PL501 PL503 PL504 PL601 PL602 PL801 PL802 PL900 PL902 PL903 SG900 SG901 SG902 SW506 SW507 SW508 SW509 SW510 SW801 TH800 VL405 . . . . . . . . . . . . . . . . . . . . .

PARTS 30001731 30001793 30006987 30007248 30009366 30009783 30009784 30014568 30017855 30018423 30018427 30025172 30027392 30028208 35000136 20000848 30015053 30001829 30018454 30006709 30001783 30009085 30019101 30001827 30006660 30001792 30001795 30016695 30016694 30001855 30000428 30000428 30000428 30016022 30016022 30016022 30016022 30016022 30017848 30001268 30014048 20141197 20143026 20147245 35000158 35000165 35000180 35000181 35000182 35000224 35004572 35005084 35008081 40016815 50043630 50048171 50048688 20140407 20140426 20140427 20141195 20141196

DESCRIPTION SN CODE FUSE SAFE 2.5A 250V 5*20MM AA CONN HOUSING 2P 7.5MM TOP AA IC 24C08 (WP) AC CONN HOUSING 4P 3.96MM TOP WHT AA DIODE UF5402 3A/200V 150A AB SOCKET IC 56P (SHRINK) AC SOCKET IC 8P (DIP) AA TERMINAL SSC 2000T AA CONN.ASSY.4/45 (HRZ&VER) IMPROVED NEW AB CNAS 2P/500 SIS W/BLK C+FER UL1007AWG24 AB CNAS 2P/500 SPK SIS W/C+FER UL1007AWG24 AB IC TDA6107JF/N3 AF SPEAKER 16R 4W F/R 50x90MM-21" SF SHARP AE AG POWER CORD SAFE EURO 2.2M SHARP W/FILTER FUSE HOLDER TK79-A (GRAY) AA FUSE ASSY.TK79-A (2.5A) AA SOCKET SCART NEW TYPE AB CONN HEADER 2P 2.5MM TOP WHT SD AA CONN HEADER 2P 2.5MM TOP BLACK AA CONN HEADER 5P 2.5MM TOP WHT SD AA CONN HEADER 5P 2.5MM TOP BD AA CABLE 1P R2.6 35 W/CLIPS AA CABL 1P/350 DIS UL1672AWG22 AA CONN HEADER 4P 5/7.5MM TOP WHT AA CONN HEADER 4P 2.5MM TOP WHT SD AA CONN HEADER 2P 7.5MM TOP WHT AA CONN HEADER 3P 5/7.5MM TOP WHT AA CNAS 5P/450 FLT W/C+CBLH UL2468AWG24 AB CNAS 4P/450 FLT W/C+CBLH UL2468AWG24 AA SOCKET CRT SAFE NARROWNECK W/GND AD SPARK GAP 300V AB SPARK GAP 300V AB SPARK GAP 300V AB SWITCH TACT VERTICAL T&R AA SWITCH TACT VERTICAL T&R AA SWITCH TACT VERTICAL T&R AA SWITCH TACT VERTICAL T&R AA SWITCH TACT VERTICAL T&R AA SWITCH SAFE ON/OFF 4A/128A JVC AC THERMISTOR 3P AD ADJ.COIL VIF 44MHZ Q=64 C=39pF AA ARTWORK SCR.ASSY.2162 (2SP) R/C 1548 SHARP (EKO2GRAY/I) (GRAY/S) LBL.BCK.CVR.ASSY (TV) (WO/UL)SHARP NUT C ZN BOTTOM M3 KNURL WASHER C ZNSY 3*6*04 (M3) SCREW C ZN YSMB M3*6 SCREW C ZN YSMB M3*8 SCREW C ZN YSMB M3*10 SCREW C SK ZN YFMB 2.9*9.5 SCREW P C AgSYF YSB 4x20 SCREW C ZN RYAKB 6x30 SCREW P C ZN YFMB 3*9.5 LOGO SHARP (D.C.-SILVER)21"SF SHARP WARRANTY CARD SHARP (ESP) CARTON BOX SHARP SHARP (2162) I/B SHARP 21LS90N(ES) P/AK44/1548/ES/POR COSMETICS BACK CVR.2162SF EKO2GRAY (I) (AK44) SNOW BOX TOP 2162SF SHARP SNOW BOX BOTTOM 2162SF SHARP BUTTON ASSY 2162 (SILVER/O.BLUE) SNOW BOX ASSY 2162 AB AM AA AA AA AA AA AA AA AA AA AA AC AB AL AD AR AA AA AD AL

EX CODE AC AD AH AB AF AH AB AB AF AF AF AQ AN AT AD AD AF AB AA AB AC AC AB AD AB AC AC AE AE AM AG AG AG AB AB AB AB AB AH AM AE AF AY AC AB AB AA AB AA AB AB AB AA AH AF AX AL BB AA AA AN AX

. . . . . . . . . . . .

20092581 20141421 20141673 20144821 20144823 20151170 20151171 20151172 20151304 20157066 30001386 30001448

AB AQ AD BH AB AH AE AE AD AW AE AF

AF BA AN BZ AE AT AN AP AM BH AP AQ

!

9

21LS-90N

REF No. . . . .

PARTS 20151662 20069673 40012331 40016859

DESCRIPTION FRONT 2162 W/H SLV285S(P)(PW/STR/S)2SPK FIRE BARRIER (I)(NATURAL -V.O.)(AK30) RUBBER PAD (RC 1542) RUBBER WASHER 2163RF (I) SHARP

SN CODE AS AA AD AA

EX CODE BD AC AL AB

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21LS-90N

How to update the Technical Information appeared on this Service Manual
1. Web site: https://www.vestelservice.com 2. Select: Technical Support 3. Login: 101278 4. Password: SHPII278 By this access you can consult the latest schematic diagram or request the Parts Listing of a concrete Production Date / Serial Number. By this way it can be also consulted the issued Technical Reports (Service Bulletins).

11

21LS-90N

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

Technical information and Production: Vestel Electronik AS Technical information re-issued: SHARP ELECTRONICA ESPAÑA S.A. Service Manual Group Engineering Dept. Polígono Industrial Can Sant Joan 08190 Sant Cugat del Vallès Barcelona Spain PRINTED BY: ON:

Think Ecology, please use

RECYCLED PAPER 12

AK - 44 CHASSIS

SERVICE MANUAL
SE00AK44CHA00
Issued: 9th March 2004

PAL B/G, I / SECAM L/L', B/G, D/K SYSTEM COLOUR TELEVISION

CHASSIS

AK-44

In the interests of user safety (required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used.

CONTENTS
TABLE OF CONTENTS ....................................................................................................... 3 INTRODUCTION .................................................................................................................. 6 CIRCUIT DESCRIPTIONS ................................................................................................... 6 INTEGRATED CIRCUIT DESCRIPTIONS ....................................................................... 13 BLOCK DIAGRAM ................................................................................................................ 22 SERVICE MODE ADJUSTMENTS ...................................................................................... 23 HOTEL MODE FUNCTIONS ................................................................................................ 30 CIRCUIT DIAGRAMS ..................................................................................................... 31 HOW TO UPDATE THE TECHNICAL INFORMATION ...................................................... 41

SHARP CORPORATION
1

This document has been published to be used for after sales service only.

AK - 44 CHASSIS

SERVICE MANUAL UPDATE LOG SHEET
Technical Report No. Technical Bulletin No. Cause / Solution Part No. Page No. Application Data /Serial No.

Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc. If only part number changes are required, just change part number directly the part number in the Parts Listing Section. If you need more information, please refer to the Technical Report (Bulletin).

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AK - 44 CHASSIS

TABLE OF CONTENTS
SAFETY PRECAUTIONS ............................................................................................................................................... 5 TV set switched off ............................................................................................................................................... .....5 Measurements ....................................................................................................................................................... 5 PERI-TV SOCKET ........................................................................................................................................................... 5 SCART 1........................................................................................................................................................................... 5 1. INTRODUCTION ......................................................................................................................................................... 6 CIRCUIT DESCRIPTIONS ............................................................................................................................................. 6 2. SMALL SIGNAL PART WITH STV2248 ..................................................................................................................... 6 2.1 Vision IF amplifier ........................................................................................................................................... 6 2.2 QSS Sound circuit (QSS versions) ................................................................................................................. 6 2.3 AM Demodulator ........................................................................................................................................... 6 2.4 FM demodulator and audio amplifier (mono versions) .................................................................................. 6 2.5 Video switch ................................................................................................................................................... 6 2.6 Synchronisation circuit .........................................................................................................................................6 2.7 Chroma and luminance processing ................................................................................................................ 7 2.8 RGB output circuit .......................................................................................................................................... 7 2.9 µ-Controller .................................................................................................................................................... 8 2.9.1 Controls .............................................................................................................................................. 8 2.9 .2 Teletext ............................................................................................................................................. 8 2.10 Video Path ..................................................................................................................................................... 9 2.11 Sound Path .................................................................................................................................................. 9 2.12 AV Input Signal Path ..................................................................................................................................... 9 2.12.1 Video and Sound ............................................................................................................................ 9 2.12.2 RGB ................................................................................................................................................ 9 3. TUNER ....................................................................................................................................................................... 9 4. DIGITAL TV SOUND PROCESSOR MSP34X0 ........................................................................................................ 10 5. SOUND OUTPUT STAGE TDA7266L/TDA7266 ...................................................................................................... 10 6. VERTICAL OUTPUT STAGE WITH TDA8174A ....................................................................................................... 10 7. VIDEO OUTPUT AMPLIFIER TDA6107 ................................................................................................................... 11 8. POWER SUPPLY (SMPS) .......................................................................................................................................... 11 8.1 Start Up ......................................................................................................................................................... 11 8.2 Voltage Regulation .......................................................................................................................................... 11 8.3 Voltage Protection .......................................................................................................................................... 11 8.4 Current Regulation .......................................................................................................................................... 11 8.5 Standby operation .......................................................................................................................................... 12 8.6 Mode transition ............................................................................................................................................. 12 8.7 SMPS Switch Off .......................................................................................................................................... 12 9. LINE CIRCUIT ............................................................................................................................................................ 12 9.1 B.C.L. Circuit (Beam Current Limiter) ........................................................................................................... 13 10. SERIAL ACCESS CMOS 8K EEPROM 24C08 ...................................................................................................... 13 11. SAW FILTERS .......................................................................................................................................................... 13 12. IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM ..................................................................................... 13 ST92195 ................................................................................................................................................................ 14 STV224X ............................................................................................................................................................... 15 UV1315, UV1316, UV1336 .................................................................................................................................. 15 TDA7266/TDA7266L .......................................................................................................................................... 17 TDA8174 ..................................................................................................................................................................18 TDA6107 ................................................................................................................................................................ 18 MC44608 .................................................................................................................................................................19 MSP34X0G ..............................................................................................................................................................19 24C08 .................................................................................................................................................................... 20

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AK - 44 CHASSIS
TDA1308 ................................................................................................................................................................ 21 SAW FILTERS ....................................................................................................................................................... 21 13. GENERAL BLOCK DIAGRAM of 11AK44 ..................................................................................................................22 14. SERVICE MENU ...................................................................................................................................................... 23 14.1 Service Menu entrance ................................................................................................................................ 23 14.2 Service Adjustments ................................................................................................................................... 23 14.3 Using Coloured Buttons .............................................................................................................................. 24 14.3.1 AVL ............................................................................................................................................... 24 14.3.2 Geometry Menu ............................................................................................................................. 25 14.3.2.1 Geometry Table ................................................................................................................ 25 14.3.2.1 Geometry Table ................................................................................................................ 25 14.3.3 Screen Adjustment ...................................................................................................................... 26 14.3.4 IF Adjustment ................................................................................................................................ 26 14.4 Auto Programming System Set Up ............................................................................................................. 25 15. OPTIONS ................................................................................................................................................................... 27 15.1 Service Registers updating regarding the Tuner ...................................................................................... 27 15.2 Registers details ......................................................................................................................................... 28 16. LANGUAGES ......................................................................................................................................................... 30 17. HOTEL MODE FUNCTIONS ................................................................................................................................... 30 18. SCHEMATIC DIAGRAMS ........................................................................................................................................ 31 19. HOW TO UPDATE THE TECHNICAL INFORMATION ........................................................................................ 41

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AK - 44 CHASSIS

SAFETY PRECAUTIONS
The service of this TV set must be carried out by qualified persons only. Components marked with the warning symbol on the circuit diagram or on the Parts Listing, are critical for safety and must only be replaced with an identical component. - Power resistor and fused resistors must be mounted in an identical manner to the original component. - When servicing this TV, check that the EHT does not exceed 26kV. TV set switched off: Make short-circuit between HV-CRT clip and CRT ground layer. Short C809 before changing IC800 and IC801 or other components in primary side of the SMPS part. Do not try to test Q801 gate source junction if C809 is charged, your meter will turn on the transistor which will discharge the capacitor resulting in a drain source short circuit. Do not discharge C809 quickly with a screwdriver etc. The very high current produced can damage the internal connections of the capacitor causing failure at a later date. Remember when checking voltages to use a return path on the same side of TR802 for the Voltmeter earth to obtain the correct readings. Measurements: Voltage readings and oscilloscope traces are measured under the following conditions: Antenna signal's level is 60dB at the color bar pattern from the TV pattern generator. (100% white, 75% color saturation) Brightness, contrast, and color are adjusted for normal picture performance. Mains supply, 220VAC, 50Hz. DO NOT CHANGE ANY MODULE UNLESS THE SET IS SWITCHED OFF The mains supply part of the switch mode power supply's transformer is live. Use an isolating transformer. The receiver complies with the safety requirements.

PERI-TV SOCKET
20 18 16 14 12 10
21 19 17 15 13 11

8
9

6
7

4
5

2
3 21

1

SCART PINING 1 Audio right output 0.5 Vrms / 1K 2 Audio right input 0.5 Vrms / 10K 3 Audio left output 0.5 Vrms / 1K 4 Ground AF 5 Ground Blue 6 Audio left input 0.5 Vrms / 10K 7 Blue input 0.7 Vpp / 75 ohm 8 AV switching input 0-12 VDC / 10 K 9 Ground Green 10 11 Green input 0.7 Vpp / 75 ohm 12 13 Ground Red 14 Ground Blanking 15 Red input 0.7 Vpp / 75 ohm 16 Blanking input 0-0.4 VDC, 1-3 VDC / 75 Ohm 17 Ground CVBS output 18 Ground CVBS input 19 CVBS output 1 Vpp / 75 ohm 20 CVBS input 1 Vpp / 75 ohm 21 Ground

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AK - 44 CHASSIS

1. INTRODUCTION
11AK44 is a 90° chassis capable of driving 20"/21" tubes at the appropriate currents. The chassis is capable of operating in PAL, SECAM and NTSC standards. The sound system is capable of giving 4 watts RMS output into a load of 16 ohms. 7 page SIMPLETEXT is provided. The chassis is equipped with a single-deck 21 pin Scart connector.

CIRCUIT DESCRIPTIONS 2. SMALL SIGNAL PART WITH STV2248
STV2248 video processor is essential for realizing all small signal functions for a color TV receiver.

2.1 Vision IF amplifier
The vision IF amplifier can demodulate signals with positive and negative modulation. The PLL demodulator is completely alignment-free. Although the VCO (Toko-coil) of the PLL circuit is external, yet the frequency is fixed to the required value by the original manufacturer thus the Toko-coil does not need to be adjusted manually. The setting of the various frequencies (38.9 or 33,8 MHz) can be made via changing the coil itself.

2.2 QSS Sound circuit (QSS versions)
The sound IF amplifier is similar to the vision IF amplifier and has an external AGC de-coupling capacitor. The single reference QSS mixer is realised by a multiplier. In this multiplier the SIF signal is converted to the inter-carrier frequency by mixing it with the regenerated picture carrier from the VCO. The mixer output signal is supplied to the output via a high-pass filter for attenuation of the residual video signals. With this system a high performance hi-fi stereo sound processing can be achieved. The AM sound demodulator is realised by a multiplier. The modulated sound IF signal is multiplied in phase with the limited SIF signal. The demodulator output signal is supplied to the output via a low-pass filter for attenuation of the carrier harmonics. The AM signal is supplied to the output via the volume control.

2.3 AM Demodulator
The AM demodulated signal results from multiplying the input signal by itself, it is available on AM/FM output.

2.4 FM demodulator and audio amplifier (mono versions)
The FM demodulator is realized as narrow-band PLL with external loop filter, which provides the necessary selectivity without using an external band-pass filter. To obtain a good selectivity a linear phase detector and constant input signal amplitude are required. For this reason the inter-carrier signal is internally supplied to the demodulator via a gain controlled amplifier and AGC circuit. The nominal frequency of the demodulator is tuned to the required frequency (4.5/ 5.5/6.0/6.5 MHz) by means of a calibration circuit that uses the clock frequency of the µ-controller/Teletext decoder as a reference. The setting to the wanted frequency is realized by means of the software. It can be read whether the PLL frequency is inside or outside the window and whether the PLL is in lock or not. With this information it is possible to make an automatic search system for the incoming sound frequency. This is realized by means of a software loop that alternate the demodulator to various frequencies, then select the frequency on which a lock condition has been found. De-emphasis output signal amplitude is independent of the TV standard and has the same value for a frequency deviation of ±25 kHz at the 4.5 MHz standard and for a deviation of ±50 kHz for the other standards. When the IF circuit is switched to positive modulation the internal signal on deemphasis pin is automatically muted. The audio control circuit contains an audio switch and volume control. In the mono inter-carrier sound versions the Automatic Volume Leveling (AVL) function can be activated. The pin to which the external capacitor has to be connected depends on the IC version. For the 90° types the capacitor is connected to the EW output pin (pin 20). When the AVL is active it automatically stabilizes the audio output signal to a certain level.

2.5 Video switching
The video processor (STV2248C) has three CVBS inputs and two RGB inputs. The first CVBS input is used for external CVBS from SCART 1, the second is used for external CVBS from FAV, and the third one is used for internal video. The selection between both external video inputs signals is realized by means of software and hardware switches.

2.6 Synchronization circuit
The video processor (STV224X) performs the horizontal and vertical processing. The external horizontal deflection circuit is controlled via the Horizontal output pulse (HOUT). The vertical scanning is performed through an external ramp generator and a vertical power amplifier IC controlled by the Vertical output pulse (VOUT). The main components of the deflection circuit are: · PLL1: the first phase locked loop that locks the internal line frequency reference on the CVBS input signal. It is

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AK - 44 CHASSIS
composed of an integrated VCO (12 MHz) that requires the chroma Reference frequency (4.43 MHz or 3.58 MHz crystal oscillator reference signal), a divider by 768, a line decoder, and a phase comparator. · PLL2: The second phase locked loop that controls the phase of the horizontal output (Compensation of horizontal deflection transistor storage time variation). Also the horizontal position adjustment is also performed in PLL2. · A vertical pulse extractor. · A vertical countdown system to generate all vertical windows (vertical synchronization window, frame blanking pulses, 50/60 Hz identification window...). · Automatic identification of 50/60 Hz scanning. · PLL1 time constant control. · Noise detector, video identification circuits, and horizontal coincidence detector. · Vertical output stage including de-interlace function, vertical position control. · Vertical amplitude control voltage output (combined with chroma reference output and Xtal 1 indication).

2.7 Chroma and luminance processing
The chroma decoder is able to demodulate PAL, NTSC and SECAM signals. The decoder dedicated to PAL and NTSC sub-carrier is based on a synchronous demodulator, and an Xtal PLL locked on the phase reference signal (burst). The SECAM demodulation is based on a PLL with automatic calibration loop. The color standard identification is based on the burst recognition. Automatic and forced modes can be selected through the I2C bus. NTSC tint, and auto flesh are controlled through I2C bus. Xtal PLL can handle up to 3 crystals to work in PAL M, PAL N and NTSC M for South America. ACC an ACC overload control the chroma sub-carrier amplitude within 26dB range. Both ACCs are based on digital systems and do not need external capacitor. All chroma filters are fully integrated and tuned via a PLL locked on Xtal VCO signal. A second PLL is used for accurate fine-tuning of the SECAM bell filter. This tuning is achieved during the frame blanking. An external capacitor memorizes the bell filter tuning voltage. A base-band chroma delay-line rebuilds the missing color line in SECAM and removes transmission phase errors in PAL. The base-band chroma delay line is clocked with 6 MHz signal provided by the horizontal scanning VCO. The luminance processor is composed of a chroma trap filter, a luminance delay line, a peaking function with noise coring feature, a black stretch circuit. Trap filter and luminance delay lines are achieved with the use of bi-quad integrated filters, autoaligned via a master filter phase locked loop.

2.8 RGB output circuit
The video processor performs the R, G, B processing. There are three sources: 1. Y, U, V inputs (coming from luma part (Y output), and chroma decoder outputs (R-Y, B-Y outputs). 2. External R, G, B inputs from SCART (converted internally in Y, U, V), with also the possibility to input YUV signals from a DVD player, (YUV specification is Y= 0.7 V PP , U= 0.7 V PP , V = 0.7 V PP for 100% color bar). 3. Internal R, G, B inputs (for OSD and Teletext display) The main functions of the video part are: - Y, U, V inputs with integrated clamp loop, allowing a DC link with YUV outputs, - External RGB inputs (RGB to YUV conversion), or direct YUV inputs, - Y, U, V switches, - Contrast, saturation, brightness controls, - YUV to RGB matrix, - OSD RGB input stages (with contrast control), - RGB switches, - APR function, - DC adjustment of red and green channels, - Drive adjustments (R, G, B gain), - Digital automatic cut-off loop control, - Manual cut-off capability with I2C adjustments, - Half tone, oversize blanking, external insertion detection, blue screen, - Blanking control and RGB output stages.

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AK - 44 CHASSIS

2.9 µ-Controller
The ST92195 is the micro-controller, which is required for a color TV receiver. ST92195D1 is the version with one page Teletext and ST92195D7 is the one with 7 page Teletext. The IC has the supply voltage of 5 V and they are mounted in PSDIP package with 56 pins. µ-Controller has the following features - Display of the program number, channel number, TV Standard, analogue values, sleep timer, parental control and mute is done by OSD - Single LED for stand-by and on mode indication - System configuration with service mode - 3 level logic output for SECAM and Tuner band switching IC 501 controls all the functions of the receiver operated by the remote control and the front panel customer controls. It produces the on screen graphics, operates tuning, customers controls and engineering controls, and also incorporates all of the Teletext functions. It also controls the video processor, the audio processor, and the tuner. The circuits just mentioned are controlled via the I²C bus. Also IC501 controls the video source switching, vertical position adjustment and the vertical linearity adjustment via its ports. An external 8K EEPROM is used by the micro. The EEPROM comes fully programmed. The main clock oscillator is 4.0 MHz crystal X501 on pins 50 and 51. Reset is provided on pin 2 via Q504. On switching on pin 2 becomes high and the controller gets reset which stays valid till a low signal comes on that pin. 2.9.1 Controls Command information from the infrared remote controller is fed through the sensor IC502 to pin 1 of the microprocessor. Operation of the customer front panel keys is detected by pin 8 that is an ADC (analogue to digital converter). Pressing a switch will connect the 5V to the ground through a particular resistor that determines the value of the voltage on pin8 at that instant. This obtained value is comprehended by the micro and the corresponding operation is performed. Refer to the following table:

Button P+ PV+ VMenu

Theoretical voltage 3.0V 4.0V 2.0V 1.5V 1.0V

Resistance R502 R503 R504 R506 R505

IC501 automatically switches from TV mode to AV1 by detecting the signal from or pin8 at the Scart connector, through it 56 pins. The picture mode is determined according to the following table:
Direct Voltage 0~2V 4,5 ~ 7 V 9,5 ~ 12 V Picture mode TV 16 :9 4 :3

2.9.2 Teletext The microprocessor IC501 performs all of the Teletext functions internally. The Composite blanking video and Sync signal (CBVS) is input to pin 33 of the micro from pin 29 of IC403. When text is selected the text graphics are output as R.G.B signals on pins 15/16/17 of the micro and fed to pins 34/35/36 of IC403. At the same time pin 18 of the micro goes high taking pin 37 of IC403 high, blanking the picture and selecting text R.G.B. input. Note: mixed mode is available and fast text with 8-page memory.

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AK - 44 CHASSIS

2.10 Video Path
The detected video signal is output from pins 18 of IC403, to sound traps Z403/404. The video is taken from the other side via the appropriate filter to Pin 18 of IC403. (1.2 p to p) Video to the Scart connectors is taken after R458 to Pin 19 of the Scart connector. The CVBS_TXT output Pin29 output is fed to IC501 Pin 34 (for Teletext). The video signal is sometimes labelled CVBS on the circuit diagram. This stands for Composite Video Blanking & Sync. The composite signal is input Pin 13 (Video input) of IC403. This IC carries out all of the luma/Chroma processing internally and also provides the customer control functions of brightness, contrast, sharpness and saturation. IC403 is I²C bus controlled and incorporates auto greyscale circuitry and internal luma/chroma delay lines. The resulting R.G.B drive is output on pins 30,31 and 32. The R.G.B passes via connector PL405 to the CRT base PCB. Here the R.G.B signal is amplified by IC901 to provide drive for the cathodes of the CRT. IC901 produces a feedback signal, which is fed to IC403 (pin 33) for blanking and auto greyscale correction.

2.11 Sound Path
The demodulated mono sound is taken from pin 55 of IC403 directly to the sound output stage IC401 Pin 7. The output signal from IC401 is Volume controlled achieved within IC403 using the I²C bus line from IC501. To limit the volume at the specified out put the A_out pin 55 is fed to IC 401 through a voltage divider R455 and R454. Muting of the output stage is provided from Pin 46 of IC501 to pin3 of IC401/6 of IC301. IN the stereo model the IF from PINS 10 & 11 of the tuner passes through Z401 and the output signal goes through pins 1&2 of IC403. The output QSS signal from IC 403 is taken from pin 11 and sent to audio processor IC700. The left channel is output on PIN 29 and the right channel output is on PIN 28. Then to IC301 after passing through a voltage divider R454/R455 for the right channel and R463/R464 for the left channel. IC403 handles also the AM modulated signals in L/L' systems at pins 1&2.

2.12 AV Input Signal Path
2.12.1 Video and Sound IC403 has three CVBS inputs at pins 18,20 and 22.The composite video signal of AV1 is taken from pin 20 of the Scart connector to pin 20 of IC403. The mono sound signal is taken from pins 2 and 6 of the Scart sockets to the switching transistors Q101. The transistor switches the audio depending on the source, and is then fed to pin14 of lC403. When AV input is selected pin 5,6,7 of the microprocessor IC50I is taken high, this switches the IC403 to external input mode via I²C BUS. This connects the video inputs on pins 20 or 22 to IC403 and the audio input on pin 14 to the audio out on pin 55 (via the internal volume control circuit) The signal paths are then as for videopath. The chassis can detect the video signals on Scart using pin 8 switching voltage at pin 56 of IC501. 2.12.2 R.G.B The R.G.B signals from pins 7,11 and 15 of the Scart connector are fed to the R.G.B input pins (25,26,27) of IC403. R.G.B operation can be enabled by either taking pin 16 of the Scart connector high, this high is fed to Pin 28 of IC403, or via the l²C bus the microprocessor sets IC403 to forced R.G.B mode in which the video processor generates its own fast blank signal. This puts the IC into external R.G.B mode and selects the inputs on pins 25,26 and 27, overriding the video input on pin 20/22. Note: when using R.G.B input the contrast, brightness and colour controls will still operate.

3. TUNER
Either a PLL or a VST tuner is used as a tuner. UV1316 (VHF/UHF) is used as a PLL tuner. For only PALM/N, NTSC M applications UV 1336 is used as the PLL tuner. UV 1315 (VHF/UHF) is used as a VST Tuner.

Channel coverage of UV1316
BAND Low Band Mid Band High Band OFF-AIR CHANNELS FREQUENCY CHANNELS RANGE (MHz) E2 to C 48.25 to 82.25 (1) E5 to E12 175.25 to 224.25 E21 to E69 471.25 to 855.25 (2) CABLE CHANNELS FREQUENCY CHANNELS RANGE (MHz) S01 to S08 69.25 to 154.25 S09 to S38 161.25 to 439.25 S39 to S41 447.25 to 463.25

(1). Enough margin is available to tune down to 45.25 MHz.

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AK - 44 CHASSIS
(2). Enough margin is available to tune up to 863.25 MHz. Noise Low band: Mid band: High band: Typical 5 dB 5dB 6 dB Max. 9 dB 9 dB 9 dB Gain All channels: Gain Taper (of-air channels): Min. 38 dB Typical 44 dB Max. 52 dB 8 dB

Channel Coverage UV1336
BAND Low Band Mid Band High Band CHANNELS 2 to D E to PP QQ to 69 FREQUENCY RANGE (MHz) 55.25 to 139.25 145.25 to 391.25 397.25 to 801.25

Noise is typically 6 dB for all channels. Gain is minimum 38 dB and maximum 50 dB for all channels.

Channel Coverage of UV1315
BAND Low Band Mid Band High Band OFF-AIR CHANNELS FREQUENCY CHANNELS RANGE (MHz) E2 to C 48.25 to 82.25 (1) E5 to E12 175.25 to 224.25 E21 to E69 471.25 to 855.25 (2) CABLE CHANNELS FREQUENCY CHANNELS RANGE (MHz) S01 to S10 69.25 to 168.25 S11 to S39 231.25 to 447.25 S40 to S41 455.25 to 463.25

(1). Enough margin is available to tune down to 45.25 MHz. (2). Enough margin is available to tune up to 863.25 MHz. Noise Low band Mid band High band Typ. Max. 6 dB 9 dB 6 dB 10 dB 6 dB 11 dB Gain Min. All Channels 38 dB Gain Taper (off-air channels) Typ. 44 dB Max. 50 dB 8 dB

4. DIGITAL TV SOUND PROCESSOR MSP34X0
The MSP 34x0G is designed to perform demodulation of FM or AM-Mono TV sound. Alternatively, two-carrier FM systems according to the German or Korean terrestrial specs or the satellite specs can be processed with the MSP 34x0G. Only the MSP 3410 does digital demodulation and decoding of NICAM-coded TV stereo sound. The MSP 34x0G offers a powerful feature to calculate the carrier field strength which can be used for automatic standard detection (terrestrial) and search algorithms (satellite).

5. SOUND OUTPUT STAGE TDA7266L/TDA7266
TDA7266L is used as the AF output amplifier for mono applications. It is supplied by +12 VDC coming from a separate winding in the SMPS transformer. An output power of 4 W (THD = 0.5 %) can be delivered into an 16 ohm load. TDA7266 is used as the AF output amplifier for stereo applications. It is supplied by +12 VDC coming from a separate winding in the SMPS transformer. An output power of 2*4W (THD = 0.5 %) can be delivered into an 16 ohm load.

6. VERTICAL OUTPUT STAGE WITH TDA8174A
The TDA8174A is a power amplifier circuit for use in 90° and 110° color deflection systems for 25 to 200 Hz field frequencies, and for 4 : 3 and 16 : 9 picture tubes. IC403 generates a vertical pulse signal VER_OUT and V_AMP that are fed to IC600 (the vertical stage IC). IC600 is supplied by a 26V DC via diode D610. It generates its own ramp signal and based on the V_AMP & VER_OUT signals it produces the vertical deflection signals that are fed to connector PL601. Vertical linearity adjustment is controlled by Q604, which is driven by the PWM output of IC501 at pin 49. Vertical position adjustment is conducted by Q606 derived by the VER_OUT signal. Switching Q606 will change the DC voltage on VOUT_2 pin, which will either lower or higher the picture. A DC level is supplied at VOUT_2 via D614 to stabilise the picture and make its position changeable.

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7. VIDEO OUTPUT AMPLIFIER TDA6107JF/N3
The TDA6107JF includes three video output amplifiers and is intended to drive the three cathodes of a colour CRT directly. The device is contained in a plastic DIL-bent-SIL 9-pin medium power (DBS9MPF) package, and uses highvoltage DMOS technology. To obtain maximum performance, the amplifier should be used with black-current control.

8. POWER SUPPLY (SMPS)
The DC voltage required at various parts of the chassis are provided by an SMPS transformer controlled by the IC MC44608 which is designed for driving, controlling and protecting switching transistor of SMPS. The transformer produces 126 V (Flat models) or 116 V (non Flat models) for FBT input, +/- 14 V for audio output IC, S + 3.3, S + 5 V and 8 V for ST92195. The ZX series of receivers incorporate a Motorola switch mode power supply using a MC 44608 regulator controller IC. The circuit provides power to the receiver in both standby and normal operation modes.

8.1 Start Up
The switch on the mains supply is fed through the mains filter network TR801, the surge limiter resistor R828, the bridge rectifier diodes D811/13/37/38, and reservoir capacitor producing approx. 320 volts D.C. to feed the switching MOSFET Q801 via the primary winding of TR802 pins 6 and 7. Start up resistor R801 feeds from a 500V coming from the mains through the adder diodes D809, D890 to pin 8 of IC800, the IC uses 9mA current source and connects it internally to VCC at pin6 allowing a rapid charge enough for start up. Then IC800 responds with the oscillator starting to oscillate at a 40 KHz frequency fixed by the IC manufacturer. The IC then produces, pulse width modulation pulses, at this frequency on pin 5 to drive the base of the switching FET Q801, that will then switch current on and off through the primary of TR802, which will in turn provides voltages in the secondary windings. The secondary winding voltages being proportional to the length of time that Q801 is turned on in each cycle. The voltage produced between pins 4 and 3 of TR802 is rectified by D804 developing aprox. 12 volts on C810, which takes over from the start up resistor to supply pin 8 of IC800. The Demag pin at pin1 offers 3 different functions: Zero voltage crossing detection (50mV), 24mA current detection and 120mA current detection. The 24mA level is used to detect the secondary reconfiguration status and the 120mA level to detect an Over Voltage status called Quick OVP. The VCC at pin6 operates between 6,6V and 13V in normal operation, when this voltage exceeds 15V then the IC output is disabled.

8.2 Voltage Regulation
After initial start up the secondary voltages of TR802 are established. These voltages then need to be regulated to the required levels. In a switch mode power supply such as this, it is the ON time of the switching FET Q801 that determines the output voltages produced. To provide regulation of the supply there is a feedback loop via an adjustable zener IC118 and an OPTO- coupler connected to pin3 of IC800. The reference voltage of IC118 is set to 2,5V to supply a B+ voltage of 115V. Any fluctuation at this pin will cause IC800 to compensate it either by increasing or decreasing the voltage at the secondary outputs.

8.3 Voltage Protection
The MC44608 offers two OVP functions: 1- A fixed function that detects when V CC is higher than 15.4V 2- A programmable function that uses the demag pin. The current flowing into the demag pin is mirrored and compared to the reference current Iovp (120mA). -Thus this OVP is quicker than normal number one as it directly senses the change in current rather than waiting for a specific voltage value, and is called QOVP. In both cases, once an OVP condition is detected, the output is latched off until a new circuit START­UP. 3- A software controlled function acts on pin52 of IC501. This pin monitors feedback from both 8V and 5V via D512, then compares these to a reference value Vref pre-set by the hardware through resistors R545, R546, R548. In normal mode operation 1.2V < Vref < 2.4V. Any voltage outside this window will cause the micro controller to force the TV to stand by mode by lowering the standby port. Refer to standby mode.

8.4 Current Protection
To monitor the current drawn by the receiver the source of Q801 is returned to the bridge rectifier through a low value resistor R807. All the current drawn by the receiver will flow through that resistor each time Q801 conducts; this will produce a voltage across the resistors proportional to the current drawn by the receiver. This voltage is fed to pin 2 of IC800 via R806. When the receiver is working normally the voltage across R807 is only a fraction of a volt and is not large enough to have any effect on IC800. Under fault conditions, if the receiver draws excessive current the voltage across R807 will rise. This voltage is monitored by the current sense input pin2.

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This Current Sense pin senses the voltage developed on the series resistor R806 inserted in the source of the power MOSFET. When I sense reaches 1V, the Driver output (pin 5) is disabled. This is known as the Over Current Protection function. A 200mA current source is flowing out of the pin 3 during the start­up phase and during the switching phase in case of the Pulsed Mode of operation. A resistor can be inserted between the sense resistor and the pin 3, thus a programmable peak current detection can be performed during the SMPS stand­by mode.

8.5 Standby Operation
As mentioned earlier the Start­up Management of MC44608 is as follows: The Vi pin 8 of IC800 is directly connected to the HV DC rail Vin. This high voltage current source is internally connected to the VCC pin and thus issued to charge the VCC capacitor. The V CC capacitor charge period corresponds to the Start­up phase. When the V CC voltage reaches 13V, the high voltage 9mA current source is disabled and the device starts working. The device enters into the switching phase. To help increase the application safety against high voltage spike on pin8 a small wattage 1k _ series resistor is inserted between the Vin rail and pin 8. After this start-up the IC can distinguish between the different modes of operation using the following technique:

8.6 Mode Transition
The LW latch is the memory of the working status at the end of every switching sequence. Two different cases must be considered for the logic at the termination of the SWITCHING PHASE: 1. No Over Current was observed 2. An Over Current was observed These two cases correspond to the two signals "NOC" in case of "No Over Current" and "OC" in case of Over Current. The effective working status at the end of the ON time memorized in