5-4.Vertical Position; 5-5.Poor Linearity - NEC MultiSync FP1370 Service Manual

5-4. Vertical Position
Check whether the DC voltages level at CN-DSB pin 12 on the DEF
PWB (PWE-624) 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-624) 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'.
･IC501 failure.
NG
･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