XOCECO H2020 Schematics
THE ALIGNMENT FLOW CHART
PIF
To fit the front cabinet,
Focus
alignment, focus, high
BTSC, secret code setting, AV function check.
Control buttons, channels, white balance, sound, hit the set
with
Factory items’ adjustment
Heatrun for 2 hours
To fit the back cabinet
B+, AGC,H-frequency
external degaussing
Preheat for 30 minutes
White balance revoltage,
X-ray protection test, sound power test, CCD, V-chip,
INSTALLATION AND SERVICE ADJUSTMENTS
GENERAL
In the majority of cases, a color television receiver will need only slight touch-up adjustment upon
installation. Check the basic characteristics such as FS、EHV and focus. Observe the picture for
good black and white details without objectionable color shading. If color shading is evident,
demagnetize the receiver.
If color shading still persists, perform purity and c onvergence adjustments. This should be all that is
necessary to achieve optimum receiver performance.
FOCUS ADJUSTMENT
Adjust the FOCUS control (on T471) for well defined scanning lines on the picture screen.
HIGH VOLTAGE CHECK
CAUTION: These is no HIGH VOLTAGE ADJUSTMENT on this chassis. Checking should be
done following the steps below.
1. Connect an accurate high voltage meter to the second anode of the picture tube.
2. Turn on the receiver. Set the BRIGHTNESS and CONTRAST controls to minimum (zero beam
current).
3. High voltage will be measured below 24kV.
4. Vary the BRIGHTNESS control to both extremes to be sure the high voltage does not exceed the
limit under any conditions.
FS CIRCUIT CHECK
The Fail Safe (FS) circuit check is indispensable for the final check in the servicing. Checking
should be done following the steps below.
- 3 -
1. Turn the power switch on and adjust customer controls for normal operation.
Check that the set returns to normal operation when pin
34 of N101 on the Main Board is grounded with jumper
Power Circuit or Horizontal Circuit
Check if the voltage across capacitor
C411 is approximately 21V.
2. Temporarily short R412 on the Main Board with a jumper wire. Raster and sound will
disappear.
3. The receiver must remain in this state even after removing the jumper wire. This is the evidence
that the FS circuit is functioning properly.
4. To obtain a picture again, temporarily turn the receiver off and allow the FS circuit more than 30
seconds to reset. Then turn the power switch on to produce a normal picture.
Troubleshooting Guide for Fail Safe Circuit
YES NO
NO
YES
Faulty
Defective Fail Safe Circuit
PIF alignment
1) Apply DC 12V to output pin of N551(pin3 of N551 ) , connect pin7 of LA76814(N101)
to GND.
2) Apply 95dBμ, 45.75MHz RF signal to the tuner's IF pin through a 1000P ceramic
capacitor. Connect the DC voltameter's⊕pole to LA76814 pin 47 , ⊙ pole to GND.
Note: For LA76814 ES01 version, the voltameter's⊕pole should connect to pin50 .
3) Adjust T202 with a non-inductive screwdriver until the reading on the DC voltameter is DC
3.6V±0.01V.
B+ CHECK
1) Prepare the test equipment.
2) Use the DC voltameter at DC 200V position to test VD551⊕, i.e. B+.
3) Connect the power plug to AC 120V/60Hz, turn on the power switch, wait for normal raster,
then adjust RP551 to make B+ = 110V±0.5V.
Test point
VD551⊕ VD556⊕ VD554⊕ VD555⊕
DC(V) 110 25 15 18
- 4 -
TEST MODE SET(CHECK)
TEST MODE ADJUSTMENT INSTRUCTION
TEST MODE adjustment is a special adjustment which is controlled by I2C BUS. The TV set has
been set at optimum mode at the factory. Except for special need, such as replacing CRT
MEMORY IC etc., it is hoped not to adjust it.
CIRCUIT DIAGRAM OF TEST MODE ADJUSTMENT
VCC
N1
LC7461M-8103
1 C3 24
2 C2 23
3 C1 22
VCC 4 C0 21
5 C4 20
6 C5 19
7 18
VCC 8 17
9 16
10 15
11 14
G1 12 13
C1 C2
C3 VD1
R1
V1
R2
PIN20
PIN15
PIN14
PIN1 PIN4 PIN2 PIN3
1
.
MENU
VOL-
3
RECALL NC PIN17
TC/AV
VCHIP IFC GEO PICTURE
PTRN DP FACT W/B PIN13
4 2
8 6 7 5 PIN19
NC 10/0 NC 9 PIN18
CH+ PROD POWER VOL+ PIN16
CH- SCAN MUTE
1. N1 LC7461M-8103 2. VD1 IR-LED
3. V1 2SC1815 4. R1 RT14-1/4W-1Ω-J
5. R2 RT14-1/4W-220Ω-J 6. C1 C2 CT1-05B-2B4-63V-220PF-K
7. C3 CD110X-6.3V-100UF-M 8. G1 455KHZ 9.VCC
H-center adjustment, V-amplitude, linearity, S-correction, V-center adjustment
1) Press the GEO button on the remote controller to enter into the ADJUST mode.
2) Select the H.PHASE item, adjust the level to make the left and right picture sysmmetrical.
3) Select the V.POS item , adjust the value to make V-center and the CRT's geometric center is in
accordance. Then select the V.SIZE item, adjust the value to make the overscan is less than or
Equate 10% .
4) Select the V.LINE item, adjust the value to make the upper and lower grid's(on the screen)
vertical distance equal. Select the V.SC item, adjustthe value to make the vertical distance from
upper grid to middle screen is equal to the vertical distance from lower grid to middle screen.
5) Press the PICTURE button on the remote controller to save the data.
White balance
1) Press the W/B button on the remote controller to enter into the ADJUST mode.
2) Set the value of item as the following table:
Name Function Default Value
R-BIA Red Bias 95 0~255
G-BIA GreenBias 127 0~255
B-BIA BlueBias 95 0~255
R-DRV Red Drive 48 0~127
G-DRV GreenDrive 7 0~15
B-DRV BlueDrive 48 0~127
3) Press the DP button , Select the Subbrishtness item ,Set the value of Subbrishtness =85, then
press "SCAN" button. Adjust the SCREEN potentiameter clockwise until a slight bright
horizontal line appears on the screen. Adjust the value of R-BIA, G-BIA and B-BIA, until the
line change white. Press " SCAN " button again. Then decrease S-BRI to a proper value.
Name of button 1 3 5 7
Function Red Drive + Green Drive + Blue Drive + Subbrishtness +
Name of button 2 4 6 8
Function Red Drive - Green Drive - Blue Drive - Subbrishtness -
4) Press the W/B button,Then press the PICTURE button on the remote controller to save the
data.
, sub-brightness adjustment
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