Epson DFX-8500 service manual C204 MAIN/DRV/DRV-B boards Component Repair 6/7

		TROUBLESHOOTING
	Table 5-6. C204 MAIN/DRV/DRV-B boards Component Repair 6/7
Symptom	Cause	Checkpoint	Solution
The head fan	IC1 on the C204	Observe the PG motor phase signal at	Replace IC1.
operation is	MAIN board is	pins 163 (FANA) and 164 (FANAX) of
abnormal.	defective.	IC1.
	Q10 or Q11 on the	Observe the head fan phase drive	Replace Q10 or
	C204 MAIN board is	voltage level for pins 25 (HFANA) and	Q11.
	defective.	17 (HFANB) of CN1. (The normal
		voltage is approximately 37 VDC.)
The PG motor	IC1 on the C204	Observe the PG motor phase signal at	Replace IC1.
operates	MAIN board is	pins 10 (PGA), 12 (PGB), 14 (PGAX),
abnormally.	defective.	and 13 (PGBX) of IC1.
	The common	Check the collector voltage of Q11.	Replace Q10 or
	switching transistor on		Q11.
	the C204 DRV board
	is defective.
	The phase switching	For transistors Q12 - Q15, observe the	if there is no output
	transistor on the C204	output signal (collector).	signal, replace the
	DRV board is		abnormal transistor.
	defective.
	Fuse F2 on the C204	Check if fuse F2 is defective.	Replace F2.
	DRV board is
	defective.
	The PG sensor is	Observe the PG sensor output signal at	Replace the PG
	defective.	pins 35 (PGENCA) and 34 (PGENCB)	sensor.
		of CN14.
	The PG home	Observe the PG HP sensor signal level	Replace the PG
	position sensor is	for pin 36 (PGHOME) of CN14.	home position
	defective.	(PG home = LOW level; other = HIGH	sensor.
		level.)
The plunger is	Fuse F3 is defective	Check if fuse F3 is defective.	Replace F3.
defective.
	IC1 on the C204	When paper is loaded into the printer,	Replace IC1.
	MAIN board is	look at the switching signal at pins 16
	defective.	(PLP) and 17 (PLN)of IC1.
	Plunger drive	Observe the Q31 collector voltage at	Replace Q31, Q30,
	transistor on the C204	paper loading.	or Q32.
	DRV board is
	defective.

Rev. B 5-21