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SERVICE MANUAL
3.1 Connect a precise static high voltmeter to the second anode (inside the high voltage cap) of the
CRT.
3.2 Plug in the supply socket (150-250V ~, 50Hz) and turn on the TV. Set the brightness and
contrast to minimum (0 A).
3.3 The high voltage reading should be less than the limited EHT voltage.
3.4 Change the brightness from minimum to maximum, and ensure high voltage not beyond the
limitation in any case.
Nominal EHT voltage: 28.8KV 1KV Limited EHT voltage: 32KV
4. Focus Adjustment
Caution: Dangerously high voltages are present inside the TV. Extreme caution should
be exercised when working on the TV with the back removed.
4.1 After removing the back cover, look for the FBT on the main PCB. There should be a FCB on
the FBT.
4.2 Power on the TV and preheat it for 15 min.
4.3 Receive a normal TV signal. Rotate knob of the FCB until you get a sharp picture.
Before Adjusting After Adjusting
Fig. 4
5. Safety Inspection
5.1 Inspection for insulation and voltage-resistant
Perform safety test for all naked metal of the TV. Supply high voltage of 3000V, 50Hz (limit
current of 10mA) between all naked metal and cold ground. Test every point for 3 sec. and
ensure no arcing and sparking.
5.2 Requirements for insulation resistance
Measure resistance between naked metal of the TV and feed end of the power cord to be
infinity with a DC-500 high resistance meter and insulation resistance between the naked metal
and degaussing coil to be over 20M .
6. SERVICE mode
6.1 To enter the SERVICE mode
Set the volume to 0 by the remote control. Then press and hold the MUTE button on the
remote control and MENU button on the TV at the same time for over 2 seconds. In the S mode,
press the POWER button to quit the S mode.
S
( S is red and other items are yellow.)
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SERVICE MANUAL
Use the / buttons on the remote control to highlight an adjustment and the / buttons
to adjust it.
The POS+/-, / / / ,1~6, RECALL, VOL+/-, MUTE and POWER buttons on the remote
control function in the S mode, but 100+, 7, 8, 9 and 0 buttons not.
6.2 Bus data
Table 3 Bus data
Data in S
Adjustment Description
Mode
OP1 7B Option set byte 1 See Table 4
OP2 48 Option set byte 2 See Table 4
OP3 FF Option set byte 3 See Table 4
OP4 F5 Option set byte 4 See Table 4
OP5 36 Option set byte 5 See Table 4
OP6 28 Option set byte 6 See Table 4
AVG Vertical output
INIT Initializing E2PROM
TAB Data check sheet See Table 5
VX00 19 4:3
VX50 01 16:9
VX99 38 Zoom
VS Set to the optimum Half vertical output
Vertical amplitude (When vertical frequency is identified to
VA Set to the optimum 50Hz, "5VA" is displayed when identified to 60Hz, "6VA"
displayed.)
SC Set to the optimum S correction
Vertical shift (When vertical frequency is identified to 50Hz,
VSH Set to the optimum "5VSH" is displayed when identified to 60Hz, "6VSH"
displayed.)
Character field starting position (When vertical frequency is
5OV Set to the optimum identified to 50Hz, "5OV" is displayed when identified to
60Hz, "6OV" displayed.)
HP Set to the optimum Parallelogram correction
HB Set to the optimum Bow correction
Horizontal shift (When vertical frequency is identified to
5HS Set to the optimum 50Hz, "5HS" is displayed when identified to 60Hz, "6HS"
displayed.)
Horizontal amplitude (When vertical frequency is identified to
5HA Set to the optimum 50Hz, "5HA" is displayed when identified to 60Hz, "6HA"
displayed.)
( continued )
10
SERVICE MANUAL
East-west pincushion correction (When vertical frequency is
5EW Set to the optimum identified to 50Hz, "5EW" is displayed when identified to
60Hz, "6EW" displayed.)
UCP Set to the optimum Upper corner correction
BCP Set to the optimum Bottom corner correction
TC Set to the optimum Trapezoidal correction
RCUT Set to the optimum Red gun cutoff voltage
GCUT Set to the optimum Green gun cutoff voltage
RDRV Set to the optimum Red gun drive voltage
GDRV Set to the optimum Green gun drive voltage
BDRV 20 Blue gun drive voltage
YDFP 0D Brightness delay PAL
YDFN 0D Brightness delay NTSC
YDFS 0D Brightness delay SECAM
YDAV 0D AV brightness delay
AGC Set to the optimum Automatic gain control (AGC)
VOL 28 Volume initial value
IFFS O3 Intermediate frequency
CL OB
AGCS 03 AGC speed
VG2B 30 VG2 brightness
SVOL 36 Volume 00
MVOL 3C Volume 25
SBRI 1F Sub brightness
MBRI 33 Brightness Max.
SCON 0C Sub contrast
MCON 3F Contrast Max.
MCOL 3F Color Max.
Table 4 Option bit setting
Bit Item Description
OP1 0 OP_HOTEL Hotel Mode: 1: Yes, 0: No
1 OP_HWSN Audio processor: 1: TDA9859, 0: No
2 OP_SUPERWOOFER Super woofer: 1: Yes, 0: No
3 OP_NTSC NTSC option: 1: Yes, 0: No
4 OP_AV2 1: With AV2; 0: Without AV2
5 OP_SVHS S-Video: 1: Yes, 0: No
6 OP_DVD DVD 1: Yes, 0: No
( continued )
11
SERVICE MANUAL
7 OP_RGB RGB 1: Yes, 0: No
0 OP_AVL AVL 1: Yes, 0: No
1 OP_AUTO_SOUND Auto sound system test: 1:Yes, 0: No
2 OP_KEY Key: 1: Standard 0: Non-standard
3 OP_OSO Switch off in vertical overscan
OP2
4 OP_NOT_3 National option (disabled)
5 OP_USER_LOGO User write-in logo option (prior to Changhong logo)
6 OP_ON_BACK Power-on auto-test background: 1: Blue, 0: Black
7 OP_FSL Slicing level for vertical sync
0 OP_ENGLISH English
1 OP_FARSI Farsi
2 OP_ARABIC Arabic
3 OP_RUSSIAN Russian
OP3
4 OP_FRENCH French
5 OP_GERMAN German
6 OP_ITALY Italian
7 OP_SPAIN Spanish
Window selection of sound PLL:
0 OP_FMWS
1: Large window, 0: Small window
OP_DIRECT_SWITCH_ Memory on: 1: Remote on if remote off; instant on if
1
ON AC off 0: Soft on
2 OP_HCO EHT: EW control 1:On 0: Off
OP4 Changhong logo display
3 OP_CHH_LOGO
1: Yes under no signal condition 0: No
4 OP_SOUND_DK Audio system DK option: 1: Yes, 0: No
5 OP_SOUND_BG Audio system BG option: 1: Yes, 0: No
6 OP_SOUND_I Audio system I option: 1: Yes, 0: No
7 OP_SOUND_M Audio system M option: 1: Yes, 0: No
OP5 0 OP_TUNER Tuner 1: Philips tuner, 0: Panasonic tuner
1 OP_AUTO_LANG0 Auto language option: English - Farsi - Arabic -
2 OP_AUTO_LANG1 Russian - French - German - Italian