Epson DFX-8500 Service Manual page 196

DFX-8500
Table 5-6. C204 MAIN/DRV/DRV-B boards Component Repair 7/7
Symptom
The self-test is IC1 on the C204
printed incorrectly MAIN board is
defective.
The head driver FETs
on the C204 MAIN
and/or C204 DRV-B
boards are defective.
The CPU (IC2) on the
C204 MAIN board is
defective.
5-22
Cause
Observe the output signal at pins 136-
181 of IC1.
Observe the voltage waveform at the
each FET drain side.
Observe the signals at pins 38 (PTS1)
and 42 (PTS2) of the IC2
Checkpoint Solution
Replace IC1.
Replace the
abnormal FET.
Replace the IC2.
Rev. B