User Control Error; Dac Output Error - NEC MultiSync FP1370 Service Manual

12-2. User control error

Check the control switches
NG
CONTROL PWB failure
OK
Digital control error

12-3. DAC output error

Check upper and lower ref. voltage
NG
Each DAC, IC802 and their ambient circuit failure
OK
Check serial communications (I
Check some pulse are presented at IC801 pin 62 (SDA) pin 64 (SCL) on VIDEO PWB
Normally, these pulses can be seen.
No pulse
Pulse
Each DAC, IC802 and their ambient circuit failure
Check the voltage at CN-CL pin 4 to 11 on the VIDEO PWB(PWE-567A),
when push the user control switches.
Check the voltage at each DAC upper and lower.
2
C-Bus method)
Digital control error
IC751 : Upper.....pin9,11,
IC532 : Upper.....pin11,13,
IC571 : V .........pin13,
DD
7-29
Lower.....pin 8
Lower.....pin10
GND.......pin8