NEC MultiSync FP1350 - Digital Control Error; User Control Error; DAC Output Error

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12-2. User control error
Check the control switches Check the voltage at CN-CL pin 4 to 11 on the VIDEO PWB(PWE-567A),
when push the user control switches.
NG
CONTROL PWB failure
OK
Digital control error
12-3. DAC output error
Check upper and lower ref. voltage Check the voltage at each DAC upper and lower.
IC751 : Upper...pin9, 11, Lower...pin 8
IC532 : Upper...pin11, 13, Lower...pin10
NG IC571 : V
DD
...pin13, GND...pin8
Each DAC, IC802 and their ambient circuit failure
OK
Check serial communications (I
2
C-Bus method)
Check some pulse are presented at IC801 pin 62 (SDA) pin 64 (SCL) on VIDEO PWB Normally, these
pulses can be seen.
No pulse
Digital control error
Pulse
Each DAC, IC802 and their ambient circuit failure