5-4.Vertical Position; 5-5.Poor Linearity - NEC MultiSync FP1350 Service Manual

5-4. Vertical Position
Check whether the DC voltages level at CN-DSB pin 12 on the DEF
PWB (PWE-568) varies by OSD vertical position control or not?
NG • IC501 failure.
• Digital control circuit failure. (see item 12)
OK
Check whether the DC voltages level at IC421 pin 8 on the DEF
PWB (PWE-568) varies by OSD vertical position control or not?
NG
• IC421 or its ambient circuit failure.
OK
• IC401, VDY or their ambient circuit failure.
5-5. Poor Linearity
5-5-1. Horizontal
Check an item 5-1.
OK
T571, Q571, IC591 IC532(pin 17) or their ambient circuit failure.
5-5-2. Vertical
Check if the vertical linearity on the screen varies by OSD "VERTICAL
LINEARITY" and "VERTICAL LINEARITY BALANCE".
NG
• IC501 failure.
• Digital control circuit failure. (see item 12)
OK
Check the D/A converter output. (IC532 pin 4,18,19)
NG
• IC532 or its ambient circuit failure.
• Digital control circuit failure. (see item 12)
OK
• Q421, Q422, Q423 or their ambient circuit failure.
• IC421 or its ambient circuit failure.
Position down
Check the voltage at IC532 pin 4,18 and 19.
The output voltages of each pin are as follows.
5V
pin 4
0V
5V
pin 18
0V
5V
pin 19
0V
7-14
V. saw wave
Position up
55 70 90 105 130 160
Vertical frequency (Hz)
0V