Epson DFX-8500 Service Manual page 192

DFX-8500
Table 5-6. C204 MAIN/DRV/DRV-B boards Component Repair 3/7
Symptom
The carriage
IC1 on the C204
operates MAIN board is
abnormally. defective.
Q16, Q17, Q18, or
Q19 on the C204
MAIN board is
defective.
IC1 is doesn't work.
IC1 on the C204 DRV
board is defective.
.
IC3 on the C204 DRV
board is defective.
5-18
Cause
Check the signals for the carriage
motor phases at pins 204 (CRA), 205
(CRB), 206 (CRC), and 5 (CRD) of IC1
Check the signals for the carriage
motor phases at collectors Q16 (CRA),
Q17 (CRB), Q18 (CRC), and Q19
(CRD).
Check the voltage level between Anode
and Kathode of ZD2 is APPROX. 6.2 V.
Check the signals for the carriage
motor phases at pins 14 (IN_A) and 10
(OUT1) of IC1..
Measure the voltage level at pins 10
(OUT1) and 5 (GP) of IC1 when the
carriage is operating. (The normal
voltage level is approximately 37
VDC.),
Observe the waveform at pin 1 of IC3.
Checkpoint Solution
Replace IC1.
Replace Q16, Q17,
Q18, or Q19.
Replace ZD2, Q34,
or Q35.
Replace IC1.
Replace IC1.
Replace IC3.
Rev. B