Epson DFX-8500 Service Manual page 189

Symptom
The 5 VDC line is IC204 is defective.
defective.
37 VDC line IC102 is defective. (If
(VP1/VP2) is this IC is defective, it
abnormal. cannot monitor the 37
VDC lines, and
printing operation
becomes abnormal.),
37 VDC line (VP3) IC203 is defective. (If
is abnormal. this IC is defective, it
cannot monitor the 37
VDC lines, and motor
operations become
abnormal.),
Rev. B
Table 5-5. C204 PSB/PSE Board Component Repair 3/3
Cause
Check the voltage level at pin 10 (V1)
and pin5 (GP).
Observe the drive waveform at pin 8
(VO) and pin 5 (GP).
When the input voltage of the minus
port (pin 6 for VP1 and pin2 for VP2) is
less than 1.3 VDC, the comparator
outputs a HIGH signal.
When the input voltage of the plus port
is bigger than 1.3 VDC, the comparator
outputs a HIGH signal.
Checkpoint
TROUBLESHOOTING
Solution
Replace IC204.
Replace IC204 or
ZD211.
Replace IC203.
Replace IC203.
5-15