Epson DFX-8500 service manual Circuit Board Repair, 1 C204 PSB/PSE Board Repair

TROUBLESHOOTING

5.2 CIRCUIT BOARD REPAIR

This section provides detailed troubleshooting methods to isolate components in the power supply or on the main board. This information is for use by service personnel who repair to the component level.

The table below provides causes, checkpoints, and solutions for different power supply circuit problems. The checkpoints include waveforms for normal operation. By referring to the checkpoints, determine the defective component. Then perform the proper repair. The table provides the following four columns:

‰￿Symptom:	Check this column for a list of common printer problems.
‰￿Cause:	Use this column to identify possible causes that could produce this symptom.
‰￿Checkpoint:	Follow the troubleshooting checks in this column to isolate your problem.<
‰￿Solution:	Repair the printer using the instructions in this column.

5.2.1 C204 PSB/PSE Board Repair

Table 5-4 indicates majour components which is used for the C204 PSB/PSE board and Table 5-4 shows the C204 PSB/PSE board component level troubleshooting.

Table 5-4. C204 PSB/PSE Board Main Parts List

Location	Description
DB1	Diode bridge
TY1	TRIAC
QF101	Switching FET for VP1 and VP2
QF201	Switching FET for VP3 and +5 VDC
IC101	PWM switching controller
IC204	+5 V regulator IC

Table 5-5. C204 PSB/PSE Board Component Repair 1/3

	Symptom		Cause	Checkpoint		Solution
No DC voltage is present			PD signal is HIGH (sent	Measure the signal level	Wait	until		the		printer
at the output . (Fan on			from the main board).	of the PD signal at CN4.	prints again.
the power supply board					Replace the E05B36 on
doesn’t rotate at all.)					the C204 MAIN board.
			The DRERR signal is	Measure the signal level	Replace		the		printhead
			HIGH.	of the DRERR signal at	driver on the C204 MAIN
				CN4.	board and/or C204 DRV-
					B board.
			CL signal is HIGH.	Measure the signal level	Wait	until		the		printer
				of the CL signal at CN4.	prints again.
					Replace the E05B36 on
					the C204 MAIN board.
Fuse	F1	blows	The line filter circuit is	Check if any of pins	Replace		the		abnormal
immediately		after	defective.	C1-C5 or R1 is shorting	element.
replacement.				the AC line.

Rev. B 5-13