XOCECO LC20Y19, Service Manual

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SYSTEM) for X210, input 9v(±0.05v) and 5v(±0.05v) to J202 and J203, adjust L210 to let x205
voltage to be 1.65v(±0.1v).
b. Solder to J201, J202, J203 and J5
3.3.2 AGC adjustment
Receiving 60dB signal of D-8 or A-7(N system), adjust RP201 to let 3v(±0.05v) of X204.
Input 100dB of antenna, the picture should not no-sync and distortion. Input 35-40db low signals,
the picture should sync and the sound normal, but the color should not disappear.
3.3.3 white balance adjustment
a. Install the unit
b. Adjust to brightness for backlight
c. Access into the D-SUB channel input 16 level gray-scale 640 x 480@60Hz signal of VGA
interface. Press , 2, 5, 8 and 0 buttons access factory menu, perform “reset ex-factory set” and
auto color.
d. Exit factory menu, input gray(H)-8 signal, adjust picture mode to “nature”.
e. Enter factory menu fixed R-OFFSET1 to 0; adjust G-OFFSET1 and B-OFFSET1 to let second
level to fit the table1.
f. Fixed R-GAIN to 200, adjust G-GAIN and B-GAIN to let seventh level to fit table1.
Table1
Color temperature 9300K
X coordinate 0.285±0.008
Y coordinate 0.293±0.008
g. Repeat e step to f step, it must be measure a true value.
h. The unit without VGA interface of 20” (N system), you should be rework c step: enter VIDEO
channel, input Gray(H)-16 for NTSC system of VIDEO interface, press , 2, 5, 8 and 0 buttons to
access factory menu, perform “reset ex-factory set” and auto color.
4. Performance check
a). TV Interfaces
Connect RF port to central signal source. Enter station search menu to auto station search. After
system adjustment is correctly, check if there is any station missing and the output of earphone or
loudspeaker and the picture is normal.
b). Interface of AV/S Terminals
input AV signal and switch to AV channel, see to the picture is normal, then input S terminal, check if
it can auto identify is normal. Check if sound is normal.
c). VGA Interface
Input VGA signal (K7253 signal generator). Separately input the several types of VGA format
signals as listed in Table 1. Then check if the picture and sound is normal. If there has been
interference to the picture then press the auto set key on the remote control once again and check if
the display is normal.
Table 1 Display Format of PC
Item
Resolution
Picture element clock
(MHz)
H-SYNC
(kHz)
V-SYNC
(Hz)
Remark
1 640 x 480 @ 60 25.175 31.469 59.900