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1
Colour Television
Chassis
A7H.1
QUADRIGA
CL 76532054_004.AI 181197
ServiceManual
Content
1 2 3 4 5 6 Technical specifications Connection facilities Safety instructions, Maintenance instructions, Warnings and notes Mechanical instructions Fault finding tree Repair facilities Block diagram Survey of test points Overview wave forms Diagram supply voltages survey Electrical Diagrams and print lay-outs (Diagram A1) (Diagram A3) (Diagram A4) (Diagram A5) (Diagram A6) (Diagram A7) (Diagram A6a) (Diagram A8) (Diagram A9) (Diagram B1) (Diagram E1) (Diagram E2) 2 3 4 6 7 7 11 12 12 12 7 Power supply Deflection Synchronisation Controls Tuner + IF + connections Video + sound Smart loader interface SVSH connection Teletext CRT (14" mn, 20"+21" nn) Clock display Radio module 8 Electrical adjustments 9 Circuit Description 10 Directions for use and Mechanical data 11 List of abbreviations and mechanical data 12 Spareparts list
5 Subject in The Netherlands without theby LV permission of Philips. Copyright prior 9870 Printed to modificationTV Service Department Published reserved 1998 Philips Consumer Electronics B.V. Eindhoven, The Netherlands. All rights reserved. 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, or 727 21644 4822 otherwise
Diagram 15 16 17 18 19 20 21 21 22 23 24 24 25 26 33
36 38
PWB 13,14 13,14 13,14 13,14 13,14 13,14 13,14 13,14
23
©Copyright reserved 1998 Philips Consumer Electronics B.V. Eindhoven, The Netherlands. All rights reserved. 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, or otherwise without the prior permission of Philips.
Published by LV 9870 TV Service Department
Printed in The Netherlands
Subject to modification
5 4822 727 21644
2
1.1
1 Technical specifications
A7H.1
Chassis specification
1
: : : :
Technical specifications
220-240V ± 10% AC; 50Hz (± 5%) 14" 43W (stand-by <= 6W) 17" 45W (stand-by <=6W) 21" 63W (stand-by <= 6W) 75W - coax 30mV 40mV 180mV ± 300Hz ± 600Hz ± 5Hz 14", 17", 21" 1 W mono execution: 4" full range round 25( 2W 3 W mono execution: 4" woofer round 16W 3W TV Systems : 1" tweeter round 16W 3W : PAL BG : PAL I : PAL BG / SECAM BGDK : PAL BGI / SECAM BGLL' : On Screen Display (OSD) green/red : 1 LED ( red for standby, green for TV- on, : "RC5" and error codes blinking red) : 0 : PLL : VHFa:48 - 118 MHz : VHFb:118 - 300 MHz : Hyper:300 - 470 MHz : UHF:470 - 861 MHz : UHF:470 - 861 MHz
Mains voltage Power cons. at 230V~
Indications
Aerial input impedance TV Min. aerial input VHF Min. aerial input UHF Max. aerial input VHF/UHF Pull-in range colour sync Pull-in range horizontal sync. Pull-in range vertical sync Picture tube range Audio output
: : : : : : : : :
VCR programs Tuning and operating system UV916E / IEC (PLL)
U944 / IEC (PLL)
:
1.2
Local operating functions
SK 1
RED MENU
-
+
CL 66532013_018.AI 280296
2
2.1
2
Connection facilities
Euroconnector:
Connection facilities
A7H.1
12- SCL to smartloader 13- Red 14- +5Sl to smartloader 15- Red 16- RGBstatus 17- CVBS 18- CVBS 19- CVBS 20- CVBS 21- Earth screen
3
v
Audio R Audio R Audio L Audio Blue Audio L Blue CVBSstatus 1 9 - Green 10- SDA to smartloader 11- Green
12345678-
(0V5 RMS 1kOhm (0V2 - 2V RMS 10kOhm) (0V5 RMS 1kOhm)
(0V2 - 2V RMS 10kOhm) (0V7pp/75Ohm) (0-2V int., 10-12V ext.)
k j k v v j j v
(0V7pp/75Ohm) (0-0V4 int.)(1-3V ext. 75Ohm) v v k j
(1Vpp/75Ohm) (1Vpp/75Ohm)
2.2
(0V7pp/75Ohm)
Location of panels
CRT
B1 P.17 E1 P.18 A1 P.9
CLOCK PANEL
E2 P.18 A6A P.15
RADIO MODULE POWER SUPPLY DEFLECTION SYNCHRONISATION CONTROL TUNER + IF + SCART VIDEO + SOUND INTERFACE TELETEXT
SMART LOADER INTERFACE
MAIN CHASSIS
A3 P.10 A4 P.11 A5 P.12 A6 P.13 A7 P.14 A8 A9 P.15 P.16
CL 76532054_005.AI 181197
4
3.1
3
A7H.1
Safety instructions, Maintenance instruction, Warnings and Notes
3
Safety instructions, Maintenance instruction,
When the set is used in circumstances with higher dust, grease or moisture levels, for example in a kitchen, the recommended interval is 1 year. The maintenance inspection contains the following actions: · Execute the above mentioned 'general repair instruction'. · Clean the power supply and deflection circuitry on the chassis. · Clean the picture tube panel and the neck of the picture tube.
Safety instructions for repairs
Figure 3-1
1. Safety regulations require that during a repair: the set should be connected to the mains via an isolating transformer; safety components, indicated by the symbol (see fig. 3.1), should be replaced by components identical to the original ones; when replacing the CRT, safety goggles must be worn.
3.3
Warnings
2. Safety regulations require that after a repair the set must be returned in its original condition. In particular attention should be paid to the following points. As a strict precaution, we advise you to resolder the solder joints through which the horizontal deflection current is flowing, in particular: · all pins of the line output transformer (LOT); · fly-back capacitor(s); · S-correction capacitor(s); · line output transistor; · pins of the connector with wires to the deflection coil; · other components through which the deflection current flows. Note: This resoldering is advised to prevent bad connections due to metal fatigue in solder joints and is therefore only necessary for television sets older than 2 years. The wire trees and EHT cable should be routed correctly and fixed with the mounted cable clamps. The insulation of the mains lead should be checked for external damage. The mains lead strain relief should be checked for its function in order to avoid touching the CRT, hot components or heat sinks. The electrical DC resistance between the mains plug and the secondary side should be checked (only for sets which have a mains isolated power supply). This check can be done as follows: · unplug the mains cord and connect a wire between the two pins of the mains plug; · set the mains switch to the on position (keep the mains cord unplugged!); · measure the resistance value between the pins of the mains plug and the metal shielding of the tuner or the aerial connection on the set. The reading should be between 4.5 MW and 12 MW; · switch off the TV and remove the wire between the two pins of the mains plug. The cabinet should be checked for defects to avoid touching of any inner parts by the customer.
1. ESD All ICs and many other semiconductors are susceptible to electrostatic discharges (ESD). Careless handling during repair can reduce life drastically. When repairing, make sure that you are connected with the same potential as the mass of the set by a wristband with resistance. Keep components and tools also at this same potential. Available ESD protection equipment: anti-static table mat (large 1200x650x1.25mm) 4822 466 10953 anti-static table mat (small 600x650x1.25mm) 4822 466 10958 anti-static wristband 4822 395 10223 connection box (3 press stud connections, 1 M ohm) 4822 320 11307 extension cable (2 m, 2 M ohm; to connect wristband to connection box) 4822 320 11305 connecting cable (3 m, 2 M ohm; to connect table mat to connection box) 4822 320 11306 earth cable (1 M ohm; to connect any product to mat or connection box) 4822 320 11308 complete kit ESD3 (combining all 6 prior products small table mat) 4822 310 10671 wristband tester 4822 344 13999 2. In order to prevent damage to ICs and transistors, all highvoltage flashovers must be avoided. In order to prevent damage to the picture tube, the method shown in Fig. 3.2 should be used to discharge the picture tube. Use a highvoltage probe and a multimeter (position DC-V). Discharge until the meter reading is 0V (after approx. 30s). 3. Together with the deflection unit and any multipole unit, the flat square picture tubes used from an integrated unit. The deflection and the multipole units are set optimally at the factory. Adjustment of this unit during repair is therefore not recommended. 4. Be careful during measurements in the high-voltage section and on the picture tube. 5. Never replace modules or other components while the unit is switched on. 6. When making settings, use plastic rather than metal tools. This will prevent any short circuits and the danger of a circuit becoming unstable. 7. Wear safety goggles during replacement of the picture tube
3.2
Maintenance instruction
It is recommended to have a maintenance inspection carried out by a qualified service employee. The interval depends on the usage conditions: When the set is used under normal circumstances, for example in a living room, the recommended interval is 3 to 5 years.
3.4
Notes
1. The direct voltages and oscillograms should be measured with regard to the tuner earth , or hot earth as this is called (see fig. 3.3) 2. The direct voltages and oscillograms shown in the diagrams are indicative and should be measured in the Service Default Mode (see chapter 8) with a colour bar signal and stereo sound (L:3 kHz, R:1 kHz unless stated otherwise) and picture carrier at 475.25 MHz.
3
Safety instructions, Maintenance instruction,
3. Where necessary, the oscillograms and direct voltages are measured with and without aerial signal. Voltages in the power supply section are measured both for normal operation and in standby . These values are indicated by means of the appropriate symbols (see fig. 3.3). 4. The picture tube PWB has printed spark gaps. Each spark gap is connected between an electrode of the picture tube and the Aquadag coating. 5. The semiconductors indicated in the circuit diagram and in the parts lists are completely interchangeable per position with the semiconductors in the unit, irrespective of the type indication on these semiconductors. 6. Manufactured under license from Dolby Laboratories Licensing Corporation. 7. DOLBY, the double D symbol and PRO LOGIC are trademarks of Dolby Laboratories Licensing Corporation.
A7H.1
5
V
CL 26532098/042 140792
Figure 3-2
tuner earth tuner aarde la masse du tuner Tuner-Erde massa del tuner tierra del sintonizador with aerial signal met antenne signaal avec signal d'antenne mit Antennensignal con segnale d'antenna con la señal de antena normal condition normaal bedrijf fonctionnement normal normaler Betrieb funzionamento normale funcionamiento normal hot earth hete aarde la terre directe heißen Erde massa calda tierra caliente without aerial signal zonder antenne signaal sans signal d'antenne .ohne Antennensignal senza segnale d'antenna sin la señal de antena stand by stand by position de veille in Bereitschaft modo di attesa posición de espera
Figure 3-3
6
4 Mechanical instructions
A7H.1
4
Mechanical instructions
Position A can be reached by first removing the mains cord from it's fixation, then loosen the carrier lips (1) and then pulling the carrier panel (2) for approximately 10 cm. Position B can be reached from position A after disconnecting the degaussing cable. Put the carrier on the line transformer side.
For the main carrier two service positions are possible (Fig. 4.1): A: For faultfinding on the component side of the main carrier B: For (de)soldering activities on the copper side of the main carrier
1 1
2
A
B
CL 76532054_006.AI 181197
Figure 4-1
5.1
5
5
S WITCH ON THE SET (with the mains switch or Remote Control)
No Picture No Sound No Sound Picture = OK
Yes White No Coulor
Fault finding tree
Fault finding tree & Repair facilities
Fault finding tree & Repair facilities
No Picture Sound = OK
No
Is Voltage +96S =>95Vdc(14") ? =>100Vdc(21") ?
Check
Disconnect 3415, 5415 and measure +96S again Reconnect 3415, 5415 Is Voltage +96S =>95Vdc(14") ? =>100Vdc(21") ? Signal "L7" = OK ?
No Yes
Yes
Voltage: +8Sb on Pin2 Ic7157, R3523 (1ohm) Controlvoltage on Pin5 Ic7157, Signal on: Pin5 Ic7015-6F, Pin50 Ic7015-6F, IC7157
Check: Check
Voltage: +160V (on CRT panel) Ic7015-6D Voltage: +14D, VG2 +8Va,+8Ve, P1/9 Ic7271 Signal on: P21 Ic7015-6D P30 Ic7015-6C P31 Ic7015-6C P7 Ic7015-6A
Check: Check:
Voltage: +8E, Signal on: p27 Ic7600 p35 Ic7015-6C Voltage: +40D R3427 Ts 7401/02 Ts7400 R3404/05 Plug 0040 Signal on: P43 Ic7015-6E
Check:
C2422 L5424 R3430 Plug 0041 Linedefl.coil.
No Yes
Measure voltage "P1" on C2516
Signal "L4" = OK ?
Activate Service-default alignment mode (SDAM) see chapter 6
Connect TV set to a variable mainstransformer.
Connect scoop to FET S-7504 Adjust mains-voltage to 40V~
No
"First check after repair"
No
Is Voltage C2516 => 300Vdc?
Yes
Signal "L5" = OK ?
LED Blinks "N" times
No Yes
Blinks "One time"
Blinks "Two times"
The FET 7504 is switching?
No
Check:
Fuse 1501, D6506, D6514, Ts7504 R3514, R3515
Check: D6502, Ts7501, Ts7502
Yes
Increase mains-voltage to 82 - 85V~
Check:
D6502, D6510 Ts7504
Check:
Ts7422 D6423 D6424
Check:
Ts7103, Ts7420, Ts7421
Check:
Supp.+9S Fuse 1502 D6503 Ic7015
I 2 C BUS error or blocked µp error
Eeprom error
A7H.1
Check :
Ic 7600
Check:
IC7685
Voltage on C2515 >100Vdc?
Yes
Check: D6501, Ts7502
No
If defect comp. is replaced: First carry out "First check after repair" "SOPS" supply is OK!
7
8
5.2
A7H.1
Functional blocks
5
Fault finding tree & Repair facilities
5.4 Service default-alignment mode (SDAM)
The service default-alignment mode is a pre-defined mode which can be used for faultfinding (especially when the TV gives no picture at all). All oscillograms and DC voltages in this service manual are measured in the service default-alignment mode. Alignment (if present) are also done in this mode.
On both the service printing on the copper and the component side, functional blocks are indicated by lines and text.
5.3
Test points
The AA5H chassis is equipped with test points in the service printing on both sides of mono-board. These test points are referring to the functional blocks as mentioned above: · · · · · · · · P1-P2-P3, etc: Test points for the power supply L1-L2-L3, etc: Test points for the line drive and line output circuitry F1-F2-F3, etc: Test points for the frame drive and frame output circuitry S1-S2-S3, etc: Test points for the synchronisation circuitry V1-V2-V3, etc: Test points for the video processing circuitry A1-A2-A3, etc: Test points for the audio processing circuitry C1-C2-C3, etc: Test points for the control circuitry T1-T2-T3, etc: Test points for the teletext processing circuitry
5.4.1
Activate the service default-alignment mode
Activate the service default-alignment mode can be done in 2 ways: 1. By short-circuiting the service pins PT1 and PT2 of the microcomputer (pin 14 of IC7600) while pressing the mains-switch. 2. From normal operation mode by pressing the button "DEFAULT" or "ALIGN" on the DST (Dealer Service Tool) RC7150.
5.4.2
Leaving the service default-alignment mode
Leaving the service default-alignment mode to normal operation can only be done by the stand-by on the remote control or by pressing diagnose 99 followed by the OK-button on the DST (so not via mains switch "off"; after mains switch "off" and then "on" again the set will start up in the service default-alignment mode again to enable easy faultfinding).
The numbering is done in a for diagnostics logical sequence; always start diagnosing within a functional block, in the sequence of the relevant test points, for that functional block.
"S" for service menu active --> Option code + Counter + software version --> Error code history --> Fig. 5.1 F4
S 0023 32000 2 3 0 0 0 - means two error codes present in the buffer; last detected error code is error code 2, previous detected error code is error code 3 The error code history buffer is cleared when the Service Menu is left by the stand-by command or by diagnose 99 command. In case the Service menu is left by the mains switch "off" the error code history buffer will not be cleared. With commands diagnose 1..5 on the DST it is possible to read out the error-buffer. This can be done on the following manner: press the diagnose button on the DST. press the number of the error position you want to read. press the OK-button on the DST. 1.0
5.4.3
Functions of the service default-alignment mode
1. All analogue settings (volume, contrast, brightness and saturation) are in the mid position. 2. Set is tuned to 475.25 Mhz 3. Delta volume settings are not used (delta volume setting = a delta on the volume setting) 4. OSD error message (present available error code) is displayed continuously 5. The +key and the -key of TV will act as search and auto store on the maximum program number. 6. Automatic switch off function (set switches "off" after 15 minutes no IDENT) will be switched off 7. Hotel mode will be disabled 8. All other functions remain normal controllable 9. Software version of the microprocessor used in that typical set is displayed in the right top corner 10. A counter in the middle of the screen indicate the normal operation hours of the set in a hexadecimal code (every time the set is switched "on" the counter is incremented by 1 hour, so +1 at the counter). 11. The "S" in the middle of the screen above the counter indicate that the set is in the service default-alignment mode 12. Option code. This code indicates the Options setting of the set. 13. Error code history; The 5 last different error codes occurred are stored in the EEPROM memory; last error code detected will be displayed on the left side (see for an overview of all possible error codes Fig. 5.1), so e.g.: 0 0 0 0 0 - means no error codes present in the buffer; 3 0 0 0 0 - means one error code present in the buffer; error code 3;
Diagnose 1 is the most actual error. So the left position of the error-buffer. Diagnose 5 displays the most right position of the error-buffer. If there is an error on the selected position the led will blink twice the error code. The error code on the DST has to be ignored. Diagnose 1..5 is an powerful tool to read out the error-buffer when there is no picture.
5.5
Option setting
All option setting are done in the normal menus. These menus can be selected by selecting the maximum TV-channel followed by pushing the volume/program selection button and at the same time pressing the volume-minus button for more then four seconds. With cursor up/down one of the items can be selected. With cursor right/left the items can be changed. New option settings are activated immediately.
5
Fault finding tree & Repair facilities
The following options can be chosen: · system SINGLE; for a BG,DK or BG/DK set MULTI F; for a BG+L+I set UHF; for a I, UHF only set Teletext YES/NO; Teletext can be selected yes or no clock YES/NO; Clock can be selected yes or no radio INT; To select internal radio tuner EXT; This means that the radio is external. In this way TV-presets could be used as radio. The installation of these kind of programs is the same as for TV programmes. Radio channels can be modulated by the system installer on TV frequencies. NO; No radio available. TV-system (bit 7 and bit 6) 00 = single PAL 01 = PAL I 10 = not used 11 = MULTI-F
A7H.1
9
·
example: option code F4 (hexadecimal presented) means a full multi set non system with teletext, clock and internal radio. F4 is in binary 1111 0100.
·
5.7
Error messages
The microcomputer also detects errors in circuits connected to the I2C (Inter IC) bus. These error messages are communicated via OSD (On Screen Display) and a flashing LED in the service default-alignment mode. (error code history buffer): 1. In normal operation. In normal operation no errors are indicated. 2. In the service default-alignment mode. In the service default-alignment mode both the "OSD error code" and the "LED error" indication will display the present detected error twice.
·
5.6
Option code
The option code is built up with 8 bits. The following table explains which option influences which bit.
Table 5-1
BIT 0(LSB) 1 Description Not used interface system 0=non system 1=system 2 3 4 5 6 7(MSB) Radio interna not uset Clock Teletext TV-System TV-System 1=clock present 1=txt present 1=radio present
Fig. 5.2 "OSD error number" (service menu) 0 1 2 3 4 5 6 Fig. 5.3 "LED behaviour" Error description Possible defective component
no led blinking LED blinks once LED blinks two times LED blinks three times LED blinks four times LED blinks five times LED blinks six times
no error general I2C bus Eeprom error TXT-error PLL-tuner error radio-module error display error IC 7685 IC 7700 / 7990 / wrong option. Item 1001 / wrong option IC 7904 / item 1910 / wrong option. IC 7951.
10
5.8
5.8.1
A7H.1
Hotel mode
Hotel-mode "on"
5
Fault finding tree & Repair facilities
To enter to hotel mode a setting must be changed in the installation menu.
5.8.2
Function of the hotel mode
volume cannot be increased above the maximum level installed. store open/close is ignored, message "LOCKED" is shown. local keys are blocked. If the blocking option is set, a message "LOCKED" is shown when a local key is pressed. all protected programs cannot be selected. To free protected programmes the remote control key "PIP on/off" must be pressed or the relevant menu item must be changed. This key works as a toggle function.
5.8.3
Hotel-mode "off"
To leave to hotel mode a setting must be changed in the installation menu. Same setting as in hotel-mode "on"
8
8.1
8
Electrical adjustments
Adjustments on the main panel (Fig. 8.1)
Electrical adjustments
A7H.1
25
8.1.1
Horizontal centring
Is adjusted with potentiometer R3354.
8.1.2
Picture height
Is adjusted with potentiometer R3407.
Adjust brightness until the DC voltage across potentiometer 3320 is 0V Adjust R3346 (B), R3330 (G) and R3310 (R) for a level of 115V on the collectors of transistors 7350, 7318 and 7330 Adjust Vg2 potentiometer until the light from the gun that first emits light is just no longer visible. Adjust the two other guns with the respective controls (3346, 3330 or 3310 until just no light will be visible
8.2.2
Grey scale (white D)
Apply a grey scale and adjust the set for normal operation. Allow the set to warm up for about 10 minutes. Adjust R3300 and R3320 until the desired grey scale has been obtained.
8.1.3
Focusing
Is adjusted with the focusing potentiometer in the line output transformer.
8.1.4
IF filter (only for sets with SECAM LL' reception possibility)
Main Chassis (Component Side)
Connect an oscilloscope to pin 1 of filter 1015. Switch on the set and select system Europe (BG/L is "low" for BGIDK reception). Adjust L5012 for a minimum amplitude.
S1 S2
EEPROM
20 21 SDAM MODE 1 42 7685 1 8 4 5
8.1.5
AFC
1. For sets with SECAM LL' reception possibility: 1. Connect a signal generator (e.g. PM5326) as indicated in point 1.6. Connect a voltmeter to pin 44 of IC7015/ 6A. 2. Adjust the frequency for 33.9 MHz and select system France (L/L' is "high" for L' reception). 3. Adjust L5040 for 3V5 (DC). 4. Next adjust the frequency for 38.9 MHz and select system Europe (L/L' is "low" for BGILDK reception). Adjust L5043 for 3V5 (DC). 2. For sets without SECAM LL' reception possibility: Connect a signal generator (e.g. PM5326) as indicated above and adjust the frequency for 38.9 MHz (for PAL I at 39.5 MHz). Connect a voltmeter to pin 44 of IC7015/6A. Adjust L5040 for 3V5 (DC).
21 22
7600 µC
7700 TXT
Connect a signal generator (e.g. PM5326) via a capacitor of 5p6 to pin 17 of the tuner and adjust the frequency for 40.4 MHz.
1 40
HOT GROUND
27 26
3354
TV
IF 5012
17
7015 VIDEO PROC
52
1
AFC 5040
AFC 5043
AGC 3021
TUNER
LOT
5 21 20 1 2
TV
3407
(upper) FOCUS SCREEN (lower)
8.1.6
RF AGC
If the picture of a strong local transmitter is reproduced distorted, adjust potentiometer R3021 until the picture is undistorted. Or: Connect a pattern generator (e.g. PM5518) to the aerial input with RF signal amplitude = 1 mV. Connect a multimeter (DC) at pin 5 of tuner. Adjust R3021 so that voltage at pin 5 of tuner is 7V5 ± 0V5 (DC).
CRT Panel (Track Side)
White R B G
Cut-off B R
3300 3320 3330 3346 3310
9 10 11 8
7 6 5 4
CL 76532054_001.AI 181097
Figure 8-1
8.2
8.2.1
Adjustments on the CRT panel (Fig. 8.1)
Vg2 cut-off points of picture tube
Apply a pattern generator (e.g PM5518) and set it to a white raster pattern. Adjust contrast and Vg2 at minimum (Vg2 with potentiometer in line output transformer to the left).
26
9.1
9 Circuit description
A7H.1
9
Circuit description
T-on; In this state the FET is conducting and energy is stored in the coil and in the output capacitor. T-off; In this state the fet is non conducting and the energy stored in the coil is fed to the output capacitor. T-dead; Fet is out of conduction and there is no energy in the coil.
Description of the power supply and the deflection part.
In this chassis all power circuits are mounted on the main carrier panel. The power supply can be divided into 2 parts: · · External power supply (not switched off by power switch) Main power supply (switched off by power switch). External power supply (with transformer item 5502). Main power supply (with transformer item 5500) and deflection.
Warning: For this power supply is valid that the +96V supply for the line output stage is not mains isolated. And therefore the line output stage and horizontal deflection coil connections on the CRT are also not mains isolated. Reason: With this supply single isolated picture tubes can be used. For a description of the main power supply and belonging deflection circuit see below.
L2-3 TS 7504
Vin
D 6504
C 2515
Vout
Down-converter
CL 66532015_013.AI 150296
Figure 9-1
1. Principle of the down-converter (Fig 9.1): The main powersupply is a self-oscillating down converter with an auxiliary winding to help the FET TS7504 to switch. When switch TS7504 is closed, the voltage on L2-3 is Vin-Vout. During this time, energy is stored in the coil and energy is delivered to the load. When switch TS7504 opens, the energy stored in the coil will be stored in the output capacitor (C2515). This is due to the fact that the current through the coil has to decrease linear. When the switch is open the current is floating through D6504, L2-3 and C2515. By controlling the duty-cycle of the switch, the output voltage can be regulated. 2. Start-up (see diagram A1): When the switch TS7504 is closed, the input voltage is placed over winding 2-3 of transformer 5500, which acts as coil L2-3 in Fig 8.1. Via resistors R3513,R3518 and R3512 the switch is turned on for the first time. Zener diode D6502 prevents that the Ugs of the FET becomes higher than 15V. When the input voltage is on winding 2-3, there is also a voltage on winding 1-2. Via winding 1-2 the correct switching voltage is obtained. The DC-part of this voltage is blocked by capacitor C2503. Diode D6510 acts as a protection in startup and in short-circuit situations. During start-up the output capacitor C2515 is empty. It takes a relative long time to charge the gate to a voltage high enough to switch on the FET. This is due to the fact the diode D6510 is conducting. When this diode is conducting, the current that would normally flow into the gate of the fet to switch on the FET, is now flowing into C2515. In this way a smooth start-up is guaranteed. 3. General way of working (Fig 9.2): The state of the powersupply can be divided into three areas (see Fig. 9.2):
4. T-on; In the T-on state, switch TS7504 is switched on. When the switch is on the voltage over resistors R3514R3515 is a direct measure for the current through winding 2-3. This is a negative voltage. When this voltage becomes below a certain level, TS7501 starts conducting and will switch off the fet. In this way it is prevented that the coil can go into saturation. This could be the case when the output voltage is very low. (long on time of the FET). When the output-voltage becomes too high during T-on the FET will be switched off. (see Output-voltage regulation) T-off; Due to the stored energy a current will start to flow through D6504, C2515 and winding 2-3. Due to the fact that the current is flowing through this circuit, a voltage with reverse polarity is on winding 1-2. In this way the fet remains off until the current through winding 2-3 reaches zero. Now a new cycle will start. The fet will be switched on and all starts over again. T-dead; If the output voltage is too high (for example in a low load situation) the FET remains off till the outputvoltage is not to high anymore. 5. Output voltage regulation: This is done by the circuit D6501, R3509, TS7502, R3505, R3507, R3510. Transistor TS7502 can only conduct when the voltage on the base is 0V7 lower than the voltage the voltage on the emitter. This means that the voltage drop over resistors R3505 and R3507 should be 5V6(zenerdiode) + 0V7(base-emitter). This is reached when the output voltage exceeds the 100V. Now transistor TS7502 starts conducting, which brings transistor TS7501 in conduction. As a consequence the gate voltage of the fet becomes very low and the fet stops conducting. As long as the output voltage is too high the fet stays out of conduction.
Icoil
Ton
Toff
Tdead
CL 66532015_014.AI 260296
Figure 9-2
9.2 Protections:
There are the following protections in this chassis: 1. Overvoltage protection: A disadvantage of a down converter is that if the switch becomes a short-circuit, the output voltage will increase to the input voltage. This could damage circuits. In this power-supply there is a protection to prevent this. If the output voltage becomes higher than 130V, zener diode D6514 starts to conduct. The Vin will be short circuited. This will blown the main fuse 1501 and protect in this way all the other circuits. 2. Short-circuit and start-up protection: The short-circuit protection works the same as the start-up protection. If the output-voltage is very low in case of a start-up or a short-
9
Circuit description
circuit condition, The gate will be charged very slowly due to the fact that zenerdiode D6510 is conducting. So the current is not only charging the gate but is also flowing into the output capacitor. In this way it takes a few milliseconds to switch on the fet. Diode D6510 takes also care that the fet never remains in his power consuming (linear) area. If the output voltage is very low, it also takes a large time before the current through winding 2-3 reaches zero. The power supplied to the circuit is in this way very low and protects in this way the circuit. 3. Other output voltages: The output voltages +8Sb,+14V +9S and +5S and +5G are made by winding 5-6. During the time that the fet TS7504 is not conducting, energy is transformed to this winding (flyback principle) and the voltages mentioned above are created. From the +9S, the +5S voltage is derived. This voltage is stabilized by transistors TS7505, TS7500 and zenerdiode D6500. D6500 is the reference voltage and TS7505 is delivering the current. When zenerdiode D6500 starts conducting, the voltage over resistor R3502 becomes high and a POR signal is created.
A7H.1
27
Stand-by: The standby signal from the uC is low in case of stand-by. Now TS7103 is brought into conduction by R3112. As mentioned before this will switch off the line-output stage completely.
9.5
Control (see schematic A5)
TMP87C-434N (all pins described from top left corner anticlock-wise) +5 (pin 42) and Power On Reset (POR) (pin 33); The +5 supply of the microcomputer (uC) is on pin 42. Via the POR on pin 33 the uC will not initialize before C2682 on pin 33 is charged to +5V (see description power supply). The initialisation will take place and the uC will start up. LED (pin 20); The LED on pin 20 will be red with "high" intensity in stand-by mode, red with "low" intensity in normal operation and will flash during RC5 reception or error messages. · In normal operation pin 20 is "high" so the current from +5A will go via R3650 to earth giving a "low" intensity In stand-by mode pin 20 will be "low" so the current from +5A will go directly to earth via pin 20 giving a "high" intensity.
9.3
Degaussing:
R3516 is a dual PTC (2 PTC's in one housing). After switching "on" the set, the PTC is cold, so low ohmic. This makes the degaussing current high. After degaussing the PTC is heated, so high ohmic. This makes the degaussing current low. After degaussing the PTC remains heated by the mains.
·
RC5 (pin 35); The commands transmitted by the RC are received by the infrared receiver 1685 and applied to pin 35 of the uC. Sharpness control (pin 6); DC control signal (2V5-5V) for sharpness control of IC7015-6B . External 2 (SVHS) (pin 8); Switching signal; "high" for SVHS mode, "low" for non-SVHS mode Operating keys (pins 10-11-12); There are 3 operating keys connected to pins 10-11-12. The status of the pins is checked every 16 msec. When pressing a key the level of a pin is pulled "low" which will be translated to the required command by the uC. AGC threshold (pin 13); DC input signal from the IF-detector IC7015-6B to the uC which reads the value of the AGC control. This input pin is only used by the factory during production for a timely increase of the tuning speed. Outside the factory this pin will not be used any more. Smart Loader -Enable (pin 9); Switching signal used for switching the Smart Loaader "high" and "low". System switching voltages L/L' - BG/L - BG/I (pins 36-37-38); Pins 36, 37 and 38 are used for system switching in the sound and video decoding part. The signals on pins 36, 37 and 38 are inverted and set to the correct level by TS7672 and TS7654 respectively. By then they are called the switching signals L/L', BG/L and BG/I (see table). The uC makes BG/L "low" in case EUROPE or UK is selected, and "high" in case FRANCE is selected. The uC makes BG/I "low" in case UK is selected, and "high" in case EUROPE or FRANCE is selected. In case FRANCE is selected and the tuning is in the lower part of the VHF1 band, the uC makes L/L' "high". In case FRANCE is selected and the tuning is in the upper VHF1 or VHF3 or UHF band, the uC makes L/L' "low". Also in case EUROPE and UK is selected the uC. makes L/L' "low". On Screen Display (OSD) (pins 27-26-23-29-28-25); Using the OSD generator, informa-tion is displayed on the screen about the tuned band, the position in the tuning range (tuning bar),
9.4
Line-circuit (Schematic A3):
The primary side of the line-circuit and the deflection coil are connected to the hot earth. The driver-circuit contains an optocoupler to create isolation between the low-signal parts and the mains. The optocoupler is driven by pin 37 of IC7015-6E via transistor TS7103. When TS7103 is not conducting,(the LED of the optocoupler is also out of conduction) TS7421 is also not conducting. In this way TS7422 will conduct and the 96V is placed over winding 2-1 of the LOT. A voltage over winding 21 of the LOT will cause a voltage over the windings 8-10, 6-10 and 9-10. Now energy will be transformed from the primary to the secondary-side and charge capacitors C2424 and C2425. C2430 will be charged to the difference of the +40D and +14D (=26V) when TS7422 is conducting. When TS7422 stops conducting, the voltage of pin 8 of the LOT will become very negative. This forces C2430 to be charged to 26V plus the absolute value of pin 8. When TS7422 starts conducting again the voltage of pin 8 of the LOT will increase and so the voltage on the anode of D6422. In this way the 160V is created. This means that during the off-time of TS7422, C2430 is charged and during the on-time of TS7422, the energy in C2430 is given to C2426. When transistor TS7103 conducts, the LED of the opto-coupler will be activated. This causes the transistor of the opto-coupler to conduct, which drives TS7421 in conduction. This brings TS7422 out of conduction. Due to this construction, this circuit is protected against missing line-drive pulses. When a linedrive pulse is missed, the line-transistor stays out of conduction, due to the fact that the diode of the opto-coupler is forced into conduction by TS7103. In this way nothing can be damaged when there is no line-drive. Winding 4-3 is an extra winding to help TS7422 to switch. On the secondary-side of the LOT there is a circuit consisting of TS7423, R3422, R3433, R3434, C2431 and C2432. This circuit creates a pulse when TS7422 switches off. This pulse indicates that horizontal flyback takes place. This information is fed to IC7015-6E to blank the picture.
28
A7H.1
9
Circuit description
whether the tuning is correct (micro search) and whether the AFC can be switched on again via the input pin 14. Pin 1 and pin 41 of the uC and the bandswitch IC7702 are not used for PLL.
system selected, sleep timer, programme number and the various picture and sound setting adjustments. In order to synchronise the OSD information with the pic-ture signal, the SANDCASTLE signal is used. From this horizontal flyback a vertical flyback pulse is derived via C2662 and C2663 and inverted fed to pin 27. The SANDCASTLE signal is fed to pin 26. The OSD generator is controlled by C2677, C2678 and L5677. The OSD FAST BLANK-ING signal is available on pin 25. The OSD-G signal is present on pin 23. 4.194 MHz oscillator (pin 31-32); The frequency of the oscillator (4.194 MHz) of the uC is determined by the crystal across pins 31 and 32. SERVICE and uP INT/EXT (pin 7); If during mains switch "on" pin 7 is shorted to earth, the Service Default Mode is activated (see chapter 8). Pin 7 is also used for internal or external audio and video switching ("low" for internal, and "high" for external). This uP INT/EXT signal together with pin 8 of the scart makes the switching signal STATUS (see diagram C). EEPROM memory and I2C (pins 39-40); The uC is connected to a non-volatile memory IC7685 (2k-bit EEPROM) via the I2C bus. The PP and programme data are stored in this memory. The system has a facility to store 69 preferred programmes (can be reduced to 39 via options) together with their tuning, band voltage and system data (the uC itself has 16k ROM internal for its software program). Stand-by (pin 19); The STANDBY switching signal is present on pin 19 of the uC. In case the status signal STANDBY is "low", the power supply will be switched into stand-by mode. Picture and sound settings (pins 2-3-4-5); There are 4 analog settings available: volume (pin 2), bright-ness (pin 3), saturation (pin 4) and contrast (pin 5). The RC networks are used to make a DC voltage level from the pulse width modulated output signal.
9.6
9.6.1
Deflection :
Horizontal deflection:
The voltage over capacitor C2422 is the same as the voltage over C2515 (96V, see Diagram A1). When TS7422 is conducting this voltage is placed over the horizontal deflection coil. This causes a linear increasing current through this coil. In this way deflection is created. When TS7422 switches of flyback takes place and it starts all over again. L5424 is used for linearity correction.
9.6.2
Vertical deflection:
Vertical deflection is based on a balance amplifier. Or TS7401 or TS7402 is conducting. This depends on the signal V-drive. If V-drive is high TS7401 conducts and the voltage of C2401 is placed over the deflection coil. Now the picture is written. When V-drive is low, TS7402 conducts and the +40V supply voltage minus the voltage over C2401 is placed over the deflection coil. Flyback takes now place. In this way deflection is generated. R3407 is used to adjust the vertical shift. With this resistor the level of the signal VFB is adjusted. R3402 and C2404 are used to damp oscillation of the deflection coil with his parasitic capacitance. The signal NIL from the uC is used to create a non-interlaced mode. This is done by creating a small DC current through the deflection coil.
9.7
A certain adjustment of these settings can be preprogrammed in the EEPROM memory as personal preference for all programmes at once (PP). Sound suppression (mute) takes place internally in the uC during the automatic transmitter search or when the received signal is interrupted (detected via the IDENT signal on pin 16). Tuning (pins 16-17-18-41-14-1); both a VST or a PLL tuner can be applied: · For VST the tuning to a transmitter in the tuner is performed via a linear variation of the tuning voltage V-vari. This tuning voltage on pin 1 of the uC (0V2 to 5V) is set to the correct level (V-vari varies between 0V and 33V) by TS7605 and the +100V from the power supply (this +100V is taken to a stabilised 33V by R3601, R3602 and D6602). The AFC (Automatic Frequency Control) signal from the IFdetector is added to the tuning voltage V-vari via R3612 to compensate tuner drift. During transmitter search pin 41 is made "high" by the uC, as a result the AFC voltage will not be added to the V-vari. If during the transmitter search an IDENT signal (from the IF-detector) is received on pin 16, the uC will check whether the tuning is correct (micro search) and whether the AFC can be switched on again via the input pin 14. For bandswitching of the 2 to 3 decoder IC7702 two switching voltages on pin 17 and 18 are used. For PLL the tuning is performed via the I2C (the V-vari also varies between 0 and 33V, but by now is only internally determined by the tuner). If during the transmitter search an IDENT signal (from the IF-detector) is received on pin 16, the uC will check
Description of diagram A7
General:
IC7015 (TDA836X) is a single-chip video processor with built in IF-detector, luminance and chrominance separator, PAL chroma deco-der, video controller, horizontal & vertical sync. proces-sor and FM sound-decoder. IC7015 has 3 possible executions: · · · TDA8360 is for PAL-only sets without external switch (no scart + cinches) TDA8361 is for PAL-only sets with external switch (with scart + cinches) TDA8362 is for PAL/SECAM multi sets with external switch (with scart + cinches)
9.7.1
9.7.2
Chrominance decoding IC7015-6C (and IC7250)
Chrominance signal originates from IC7015-6B (see diagram A6) and internally applied to the PAL chroma decoder IC70156C. For SECAM chroma decoding IC7250 is used which obtains its chroma signal via pin 27 IC7015-6C (see pin 27 description). The PAL chroma signal is fed via a pre-amplifi-er and a burst demodulator to the PAL R-Y and B-Y demodulator (all in IC7015-6C). The 4.43 MHz reference crystal for locking the chrominance oscillator of both chrominance decoders IC7015-6C and IC7250 is present on pin 35 of IC7015-6C. Pin 27 has 2 functions; PAL only mode or PAL/SECAM mode (DC controlled) and chroma output for feeding the chromasignal to the SECAM chroma decoder IC7250:
·
9
Circuit description
· For PAL/SECAM sets pin 27 should be > 5V5 (via R3243) to put IC7015-6C in the PAL/SECAM mode; by then IC7015-6C is in PAL decoding mode and via pin 27 feeds through the chroma signal to the SECAM chroma decoder IC7250 (so IC7015-6C searches for PAL and IC7250 searches for SECAM). For PAL only sets pin 27 should be < 5V5 (via jumpers 4201 and 4202) to put IC7015-6C in the PAL-only mode. ·
A7H.1
29
switch into external mode for displaying RGB from scart (via pins 22, 23 and 24 IC7015-6D) F. BL. TXT fast blanking signal from teletext; this signal is "high" (> 1V) to switch the RGB source select switch into external mode to display teletext (via pins 22, 23 and 24 IC7015-6D).
·
Bidirectional com-munication line between pin 32 of IC7015-6C and pin 1 of IC7250 both IC7015-6C and IC7250 "know" whether a PAL or a SECAM signal is detected: · · On AC level there is a 4.43 MHz calibration signal for calibration of the PLL and chroma cloche filter of IC-7250. On DC level there is a PAL/SECAM switching line enabling automatic selection of IC7015-6C or IC7250 to supply R-Y and B-Y to the delay line IC7271. If IC7015-6C has detected a PAL signal, pin 32 IC7015-6C becomes 1V5 (test point V7 is 1V5 DC). By then the demodulated R-Y and B-Y will be fed to the output pins 30 and 31 of IC-7015-6C and so to the delay line IC7271. If IC7015-6C has not detected a PAL signal, pin 32 IC7015-6C becomes 5V (test point V7 is 5V DC). By then the demodulated R-Y and B-Y will not be fed to the output pins 30 and 31 of IC7015-6C. If IC7250 has detected a SECAM signal pin 1 IC7250 becomes "low" (test point V7 is 3V5 DC). This "low" pin 1 IC7250 sinks a typical 150 ÿA from the high (5V) pin 32 IC-7015--6C via R3291. Only in case the current sinked from pin 32 IC7015-6C to pin 1 IC7250 is typical 150 ÿA, only by then IC7015-6C "knows" that IC7250 has detected a SECAM signal. The SECAM demodulated R-Y and B-Y are fed to the delay line IC7271 via output pins 9 and 10 of IC7250.
BCI; If the beam current increases, the BCI-signal (Beam Current Info) decreases. If beam current is too high the CONTRAST is pulled down to reduce contrast.
9.8
CRT panel (Schematic B1)
RGB amplification by TS7300,TS7310 - TS7320,TS7330 TS7340,TS7350 respectively. Cut off point adjustment for adjusting the R, G and B guns to start and stop emitting at the same correct level. Via R3310, R3330 and R3346 the DC level of the collec-tors TS7350, 7230 and 7310 and so the DC level of the guns are adjusted. White D adjustment for adjusting the correct balance between R, G and B signal. · Via R3310 and R3320 the amplitude of R and B signal can be adjusted to the amplitude of G The base DC-voltage of the RGB-ampli-fiers is equal to the black level of the RGB signals Picture tube flash protection: Spark gaps in the PWB of the picture tube panel (built-in in the picture tube holder) Resistors in series with the RGB electrodes 3315, 3335 and 3355 limiting the current through the guns Diodes 6314, 6334 and 6354 conduct at flashover and so do not allow a higher voltage at the guns as approx. 160V
·
· ·
SECAM VCR identifier panel; this panel is only used in sets for SECAM LL" and SECAM DK and is used to force IC7015-6C in SECAM mode (so select IC7250) at playback of a SECAM VCR tape. · In PAL mode test point V7 1V5 DC, in SECAM mode test point V7 is 3V5 DC; For both these modes TS7263 conduct, TS7262 does not conduct. In case TS7262 does not conduct the PLL frequency is determined by C2261 and C2264 only. In case of no correct SECAM decodification (e.g. black and white signal or SECAM VCR playback), test point V7 is 0V7 DC; TS7263 does not conduct and so TS7262 conduct. The time constant of the PLL filter is shifted as by now C2262 is switched in parallel to C2261-2264. In this way IC7015-6C is forced in the SECAM mode.
Peak beam current limiter; If the beam current is too high, the current though resp. R3314, 3334 and 3339 is high. The diodes 6310, 6330 and 6350 conduct and so TS7205, 7218 and 7227 can not supply more current to the guns and so the beam current is limited.
9.9
Sound processing (See schematic A7).
Two sound paths can be determined: · For BG, I and DK systems FM modulated intercarrier sound (sound extracted from baseband CVBS from IF detector) For LL' systems AM modulated quasi-split sound (sound extracted directly from the tuner). FM demodulation; For FM modulated sound the sound signal is filtered through filter 1135 or 1136 from the baseband CVBS signal. For BGILL' sets the switching signal BG/I is used to select the correct crystals: For BG reception BG/I is "high": sound path via 1135 (5.5 MHz) is selected as D6171 conducts sound path via 1136 (6.0 MHz) is blocked as TS7170 conducts and so D6170 does not conduct For I reception BG/I is "low": sound path via 1135 (5.5 MHz) is blocked as D6171 does not conduct sound path via 1136 (6.0 MHz) is selected as TS7170 does not con-duct and so D6170 conduct
·
·
9.7.3
Video controller IC7015-6D
RGB-dematrixing dematrixes the -(R-Y), -(B-Y) and the Y signals to RGB signals; the sandcastle pulse coming internally from IC7015-6E synchronises the RGB dematrixing and suppresses the RGB signals during line and frame flyback. Analog controls by the uC for contrast (0-4V5), brightness (0-5V) and satura-tion (0-2V5). Fast blanking and RGB-source select; Via the FAST BLANKING signal on pin 21 of IC7015-6D both the fast blanking and the RGB source select is realised: · OSD FAST BL from the OSD generator; this signal is "high" (> 1V) to insert the OSD characters (green or red OSD depending on the version). F. BL. SCART fast blanking signal from pin 16 of the scart; this signal is "high" (> 1V) to switch the RGB source select
·
For PAL BG or PAL I only sets only 1135 is used (resp 5.5 MHz or 6.0 MHz).
·
30
A7H.1
9
Circuit description
· Bottom switch in IC7140 selects CVBS-INT (pin 12) or CVBS-EXT (pin 13) by the same control voltage as on pin 9 IC7140 ("low" for internal and "high" for external). The output signal on pin 14 will be fed to the teletext decoder.
For PAL BG / SECAM DK sets the 5.5 MHz (1135) and 6.5 MHz (1136) are both used in parallel (no switching possibility). FM-mono sound demodulation IC7015-6F FM mono sound demodulation takes place in IC7015-6F. No ad-just-ment is required for BG or I demodulation as automatic PLL tuning (4.2 to 6.8 MHz). Pin 1 of IC7015-6F is used as: · · · Input for defining the sound frequency characteristic by deemphasis C2112 Input for positive / negative switching of IC7015 (AFC and AGC) via the status signal BG/L from Y/C Output for feeding the FM demodulated sound to IC7140 source select.
Amplification and volume control IC7157; IC7157 (TDA7056A) amplifies the LF audio signal to nominal 3W output between pin 6 (+ signal) and pin 8 (- signal). Volume control on pin 5 of IC7120 varies between 0V4 and 1V5. Anti switch-off plop; When the set is switched "on" C2157 will be charged to approx. +12V via R3157 and D6113. When the set is switched "off", the +12B drops very fast. As a result the anode of D6112 also decreases very fast up to approx. -13V (C2157 tries to hold its voltage); volume control signal on pin 5 IC7157 is pulled down too via zener D6112, so no sound plop can be heard at switch "off" (D6110 prevents the VOLUME control signal becoming negative).
Source select between FM sound or AM / AUDIO IN sound (pin 6 IC7015-6F) is done via pin 16 IC7015-6B (diagram A6). AM demodulation; Via the double bandpass characteristic of SAW-filter 1101 the required fre-quency spectrum is fed to the AM demodulator IC7125. The double characteristic is necessary because for the L system the sound is at 32.4 MHz and for L' at 40.4 MHz controlled by switching signal L/L'. · For AM sound system L' the SAW filter 1101 should passes though 40.4 MHz. For L' reception L/L' is "high", so TS7126 conduct: sound path via input pin 2 of 1101 is blocked as D6116 blocks sound path via input pin 1 of 1101 is selected; as TS7126 conducts TS7127 does not conduct, pin 1 1101 is "high", so D6115 conducts For AM sound system L the SAW filter should passes though 32.4 MHz. For L reception L/L' is "low", so TS7126 does not conduct: sound path via input pin 2 of 1101 is selected as D6116 conducts sound path via input pin 1 of 1101 is blocked; as TS7126 blocks TS7127 conducts, pin 1 1101 is "low", so D6115 not conduct
9.11
TXT (schematic A9):
For teletext there are two possibilities: Teletext on board of the main-chassis (1 page only). Teletext on the system card.
OPTIONAL! In sets with a system card there is an additional panel present (schematic G). This extra panel is present due to the fact that sending TXT-information from systemcard to the teletextdecoder takes too much time (Too much time of the I2C-bus ). The uP of the main-chassis is the master of the I2C-bus. To overcome the problem that the system card, which communicates with the teletext-decoder over the I2C-bus, uses too much time of the bus, the mP of the system card and the teletext decoder are released from the bus. See the picture 9.3: To release the system card from the bus of the set, the RELBUS signal comming from pin 41 of IC7600 is used. This signal is used as an input of IC7990 of the FAST TEST panel.
·
The demodulated signal on pin 6 of IC7125 is supplied to the source selection switch in IC7140 via TS7142 (TS7142 only conducts if the IDENT_MUTE AM signal is "high" so CVBS detected). C2126 and 2127 are AGC related storage capacitors.
9.12
Smart loader panel (schematic A6a):
The smartloader is an adapter which can be used to program the settings of a set. Once a set is programmed, this information can be stored in the smart-loader. Now the smartloader is ready to program all the other sets. If information from a set is written in the smart-loader, the information in the smartloader is checked if the transfer of the data happend correctly. This is done to prevent that all the other sets are programmed wrongly. The smart-loader panel is an analog switch (IC7930) to connect the signals SCL, SDA ,GND and +5V to the smartloader. This switch is controlled by pin9 of IC7600 (uC).
9.10
Source selection IC7140
STATUS is "high" for internal and "low" for external mode. BG/ L is "low" for FM sound (BGIDK) and "high" for AM sound (LL'). · Top switch in IC7140 selects between AM sound (pin 5) and AUDIO in from SCART + audio cinch (pin 3) controlled by pin 9. Pin 9 is controlled by the inverted STATUS signal (TS7141), so "low" for internal AM-sound and "high" for external SCART + AV sound. D6141 and R3144 are used to keep the IDENT.VCR status signal "high" in external mode as otherwise the TV would switch "off" after 15 minutes (normally if 15 minutes no IDENT then the uC will switch off the set). The output of this selector (pin 4 IC7150) is fed to input pin 6 of the FM-demodulator IC7015-6F. Here selection is made between FM sound and "pin 6 AM or EXT sound" by pin 16 IC7015-6B (INT/EXTsignal). Middle switch in IC7140 selects between AM (pin 1) and FM sound (pin 2) for the AUDIO OUT signal which is used for the SCART + AV sound output. This switch is controlled by pin 10 (BG/L is "high" for AM pin 1, "low" for FM pin 2).
9.13
The clock panel (schematic E1):
The clock-panel is fully controlled by the I2C-bus. The four 7segment digits are driven multiplexed two by two. The MX1 and the MX2 signal are used to select the correct display. If MX1 is high then TS7954 and TS7955 are conducting. Display 7957 and display 7959 are now supplied. The information, to display, are on P1..P7 and on P9..P15 of IC7951. If MX2 is high then the other two displays are selected. MX1 and MX2 are never high at the same time. P8 of IC7951 is used to activate the leds
·
9
Circuit description
alarm and message. P16 of IC7951 is used to activate decimal point. IC7951 is supplied by +5V on Pin13.
A7H.1
31
9.14
The radio module (schematic E2): IF PRESENT !!
The radio-tuner is fully controlled by the I2C-bus. The input is at the antenna plug and the low frequency outputs are at pin 5
and pin 6. These outputs are added by R3904 and R3905 to create a mono signal. This signal is fed to pin 2 of IC7901. At pin 2 of these IC is the audio signal of the tv-signal. With the signal SEL-RADIO it is possible to select the sound of the TV or of the radio-tuner. If SEL-RADIO is "high" then transistor TS7902 is conducting. Pin 10 of IC7901 becomes "low" and the radio-signal is selected.
REL-BUS 1001
Tuner
IC 7600 SDA UC-TV SCL
IC 7990 UC system card
EEPROM
TXT on system card 7700 or TXT on system card
CL 66532013_015.AI 280296
IC 7685
Figure 9-3
Signals Connectors TVside pin Smart connector SM1 system side 1 2 3 4 5 6 7 8 Electrical specification
SCL_DCM SDA_DCM GND_I2C GND +12E +5E Audio_Alarm POR
FSE1 FSE1 FSE1 PS1 PS1 PS1 MR1 PS1
1 3 2 4 5 6 single pin 7
Clock signal: See I2C specification Data signal: See I2C specification Ground I2C Ground Power +12Vdc+/- 5% ripple < %. Iomax = 100mA +5Vdc +/- 5% ripple < 2%. Iomax = 600mA Audio input low frequency. Vin< 500mV rms. Input imp > 10K Reset signal from TV to DCM micro controller. Low (0V) = active; High (5V) = Not active. Active = 0 V. Disactive = 12V.
Status
MS12
single pin
9
32
A7H.1
GND 4( 1( GND-12C SDA +5V )4 )5 )6 3( STATUS 4( MS12 )9 ) 10 +5V 1(
1
) 1 GND PS1 SCL 2( 3( 4( GND +12E +5E AUDIO-ALARM RESET STATUS NC ) 11 ) 12
3
1( )2 )3 GND-12C SDA
FSE1 )1 SCL
SM1
SDA 3( 2( 3( GND +12A +5V RESET AUDIO-ALARM )8 MR1 )7 7( 6( 5( 4(
) 2 SDA
SCL 2(
) 3 SCL
Figure 9-4
+5E 1(
) 4 +5E
SYSTEM CARD
9
DISPLAY/CLOCK
MAIN CHASSIS 1010
SCL 2( SDA 3( GND 4( SL-EN 5( SDA-SL 6( SCL-SL 7( +5SL 8(
5 SCART PLUG 2 4 6
NC NC ) 13 ) 14 NC NC
Circuit description
SM1 ) 1 SOUND-OUT 1 ) 2 SOUND-OUT 2
MS1
SOUND-OUT 1 1(
7
8 9
SOUND-OUT 2 2(
) 15
10 11 12
NC ) 16 ) 17
13 0043 14
SMART LOADER
SECOND LS
NC NC ) 18
16 18 20
NC ) 19 ) 20 NC NC
15 17 19 21
10 Directions for use.
10 Directions for use.
A7H.1
33
34
A7H.1
10 Directions for use.
10 Directions for use.
A7H.1
35
SK 1
RED
-+
MENU
1 2 3 4 5 6 7
8 9 10 11 12 13 14 15 16 17 18 19 20 21
STYLING 191.AI 090198
LED
MENU- P +
IR
1 2
8 9 10 11 12 13 14
15 16 17 18
19 3 4 5 6 20 7
STYLING 198.AI 280598
36
+183V (+163V)
11 List of Abbreviations
A7H.1
11 List of Abbreviations
Switching signal from mC; "low" for BGIDK reception (negative modulation, FM sound), "high" for LL' reception (positive modulation, AM sound). The mC makes BG/L "low" in case EUROPE or UK is selected, and "high" in case FRANCE is selected. BG/I Switching signal from mC; "low" for I reception (6.0 MHz FM sound), "high" for BG reception (5.5 MHz FM sound). The mC makes BG/I "low" in case UK is selected, and "high" in case EUROPE or FRANCE is selected. BRIGHTNESS Control signal (from mC, but on DC level via RC network) for brightness control of the video controller IC7015-6D (0-5V) C Chrominance part of the video signal; this signal is also directly input at the SVHS plug CCT Computer Controlled Teletext CONTRAST Control signal (from mC, but on DC level via RC network) for contrast control of the video controller IC7015-6D and the teletext decoder (0-4V5) CVBS Colour Video Blanking Synchronisation CVBS-EXT Incoming CVBS signal from pin 20 of scart to the external input pin 15 IC7015-6B CVBS-INT Outgoing CVBS signal from sound trap on pin 7 IC7015-6A (IF detector) to output pin 19 of scart CVBS-TXT CVBS signal coming from the CVBS-INT or CVBS-EXT (IC7140 source select) to the teletext decoder EEPROM Electrical Erasable Programmable Read Only Memory ESD Electrical Static Discharge EXTERNAL 2 (SVHS) Switching signal from mC to input circuitry IC7015-6B; "high" for SVHS mode, "low" for non-SVHS mode External power supply Separate supply to supply the clock, buzzer and the system card Extra power supply Separate supply to supply the clock and the radio module in a non system set FAST BLANKING Fast blanking signal made by adding the OSD, TXT and SCART fast blanking signals. FAST-BL-SCART Fast blanking input signal from scart which is added to the other fast blanking signals to control the video controller IC7015-6D FAST-BL-TXT Fast blanking signal from teletext which is added to the other fast blanking signals to control the video controller IC7015-6D ff Filament (heater voltage) from LOT to the picture tube FLOF Full Level One Feature FM FM demodulated sound from the FMdemodulator IC7015-6F to source select IC7140 G-SCART Green input signal from the scart to the video controller IC7015-6D G-TXT Green input signal from the teletext decoder to the video controller IC7015-6D H.DRIVE Horizontal drive signal from IC7015-6E to line output stage HOR FLYBACK Horizontal flyback pulse (15625 Hz) used for locking the horizontal oscillator in IC7015-6E I2C Digital control bus of the microcomputer IDENT.VCR Status signal which is "high" in external mode; this signal overrides the IDENT from IC70156A as otherwise the TV would switch "off" after 15 minutes (normally if 15 minutes no IDENT the mC will switch off the set). IDENT1 IDENT signal coming from IC7015-6A used for muting the AM sound signal in case no CVBS is detected. IDENT1 is "high" in case CVBS is detected and so TS7142 only conducts in case CVBS is detected by IC7015. BG/L
+29V +12E +12S
+8A +8L +5A +5C +5D +5E +5F +5G mC 16/9
AFC AGC THR
AGC AM SOUND/AUDIO IN
+183V/163V supply voltage from the LOT to the picture tube panel +29V supply voltage from the LOT to the frame amplifier IC7400 +12V supply voltage from the extra power supply to radio-module +12V supply voltage from the SMPS to the sound output amplifier and the line drive circuitry +8V supply voltage from the SMPS for the whole small signal part +8V supply voltage from the LOT to the supply voltages +5C and +5D for teletext processing +5V supply voltage from the SMPS to the mC and periphery. +5V supply voltage from +8L to teletext processing +5V supply voltage from +8L to teletext processing +5V supply voltage from the extra power supply to the clock +5V supply voltage from +8L to teletext processing +5V supply voltage from the SMPS for the LED and the keyboard Microcomputer Switching signal from the mC to the frame amplifier used for switching the frame output stage in 16/9 mode; "high" for 4/3, "low" for 16/ 9 Automatic Frequency Control DC input signal from the IF-detector IC70156B to the mC which gives the value of the AGC control (only used by the factory to timely increase the tuning speed) Automatic Gain Control AM demodulated sound signal or AUDIO-IN signal from scart or audio cinch; this signal is fed to IC7015-6F for source select Aquadag on the rear side of the picture tube to pin 8 of the LOT Automatic Table Setting (auto install system for Germany only) Incoming audio signal from pin 2 and 6 from scart or the audio cinch. Both signals go to source select IC7140 Outgoing audio signal from pin 15 IC7140 to pin 1 and 3 from scart AV switching signal (0V aerial, 4V SVHS, 8V scart) with chrominance part of the SVHS signal (C) superimposed on it. Blue input signal from the scart to the video controller IC7015-6D Blue input signal from the teletext decoder to the video controller IC7015-6D Switching signal from mC for bandswitching to the 2 to 3 decoder IC7002 Switching signal from mC for bandswitching to the 2 to 3 decoder IC7002 Baseband CVBS signal from the IF-detector IC7015-6B to the FM-demodulator IC7015-6F Beam Current Info; If beam current increases the BCI signal decreases. BCI is used for contrast reduction (if beam current is too high) and picture correction (if beam current increases (more white), EHT decreases so picture will become too big, BCI decreases and the picture will be corrected) Sound system BG/I/DK/LL' indicates frequency distance between sound and picture carriers (5.5 MHz for BG, 6.0 MHz for I, 6.5 MHz for DK and LL')
AQUA ATS AUDIO-IN
AUDIO-OUT AV+C
B-SCART B-TXT BAND-1 BAND-2 BASEBAND CVBS BCI
BG/I/DK/LL'
11 List of Abbreviations
IDENT2 Status signal from IC7015-6B; "low" for no CVBS signal (horizontal sync not present), "high" in case CVBS signal is present (horizontal sync present) from the IF-detector IC7015-6B to the mC. Intermediate frequency signal from the tuner to the AM-demodulator IC7125 Integrated Video input processor and Teletext decoder Switching signal from mC; "low" for BGIDKL (picture at 38.9 MHz) reception, "high" for L' reception (picture at 33.4 MHz). In case FRANCE is selected and the tuning is in the lower part of the VHF1 band, the mC makes L/L' "high" In case FRANCE is selected and the tuning is in the upper VHF1 or VHF3 or UHF band, the mC makes L/L' "low". Also in case EUROPE and UK is selected the mC makes L/L' "low". Non Inter Lace; 25 Hz block-shaped signal from teletext to the frame amplifier for coinciding the odd & even frames Fast blanking info from OSD generator in mC to video controller IC7015-6D for blanking the RGB info to enable OSD-G insertion which is added to the other fast blanking signals to control video controller IC7015-6D Green info from OSD generator in mC to the video controller IC7015-6D for inserting green OSD info on the screen Power On Reset; ensures the mC starts up its software only if the power supply of the mC itself is high enough Personal Preference Protection signal from frame IC7400; in case the vertical flyback generator in IC7400 is not activated, the voltage on pin 8 IC7400 becomes < 2V. By then the protection circuit in IC7400 will make pin 7 "high" overriding the HOR FLYBACK and SANDCASTLE. The constant "high" sandcastle is fed to the chrominance decoders (IC7015-6D and IC7250) and so the picture will become "black" Pin reserved for pay-tv applications in the future Red input signal from the scart to the video controller IC7015-6D Red input signal from the teletext decoder to the video controller IC7015-6D Random Access Memory Release bus signal. Read Only Memory Sandcastle signal from IC7015-6F to delay line IC7271 and SECAM chroma decoder IC7250 Sandcastle signal from IC7015-6F to mC. Control signal (from mC, but on DC level via RC network) for saturation control of the video controller IC7015-6D (0-2V5) Surface Acoustic Wave; high precision bandpass filter Scart overrule signal. Clock line of the I2C-bus Data line of the I2C-bus Service Default Alignment Mode; predefined mode for faultfinding (see chapter 8) Control signal on DC level (0-5V)