No. 51957
GM-P421U
GM-P420UG
40
Item
Test equipment
Test points
Ad justment
locations
Ad justment procedure
AD INPUT
offset (1080i)
adjustment
Oscilloscope
Video signal
generator
TP-PR
TP-PB
(MAIN PWB)
WG11
WG13
1. Input the 1080i whole black video signal to the COMPONENT
terminal.
2. Connect the probe of the oscilloscope to the MAIN PWB TP-PR
(31 pin of IC 205 - the highest bit).
3. Adjust the values with the
<
SERVICE MENU
>
WG11 (AD
input offs et) so that the brightness at the Low (0V) and High
(5V) of the digital signal voltage corresponding to the picture
signal duration become uniform (or the same ratio of
appearance). Although there are s everal kinds of states in (B),
adjust the value within 2-3 from the initial value.
4. In the same manner as for 3. above, connect the probe of the
oscilloscope to the MAIN PWB TP-PB (53 pin of IC 205 - the
highest bit) and adjust the value with the
<
SERVICE MENU
>
WG13 (AD input offset).
RGB offset
(NTSC)
adjustment
Oscilloscope
NT SC
Video signal
generator
CH01
WC04
(B cut off)
WC06
(B cut off)
1. Input the composite video signal ramp pattern to the VIDEO A
terminal.
2. Change the value in the
<
SERVICE MENU
>
CH01 from “0”
to “2” to enter the tes t mode for RGB balance.
3. Adjust the values in the
<
SERVICE MENU
>
WC04 (R cut
off) and WC06 (B cut off) so that the 3 lines on the left part of
the PDP s creen are aligned. Keep the WC05 (G cut off) intact.
4. Return the value in the
<
SERVICE MENU
>
CH01 from “2” to
“0”.
(A) WG11 Too low
1 Horizontal duration
Picture signal duration
Increase the
value
(B) Sat e of an opt imum
adjustment
(C) WG11 Too high
5V
0V
5V
0V
5V
0V
Decreae the
value
(RAMP pattern)
Align the 3 lines on the left part.