Epson Photo750 manual Repair of the Control Board

EPSON Stylus Photo 750 Revision A

3.4 Repair of the Control Board

This section describes the problems related to the power supply board. The table below provides various symptoms, likely causes, and checkpoints. The checkpoints refer to waveforms, resistance, and other values to check to evaluate the operation of each component.

Table 3-7. Repair of the Control Board

Sympto	Condition	Cause	Check point	Solution
m
			Check +5VDC line(Pin 7 of IC8) and
			reset signal (Pin 2 of IC8).
		Reset	5VײÝ	Replace
		circuit is
				IC8.
		broken.
			/RESET

		ROM is not	Check that the waveform of Pin 11	Replace
The		selected
			of IC3 reverses High/Low.	T1.
printer		correctly.
	CPU does
does not
	not work.	RAM is		Replace
operate at
		broken.		Q1.
all.
			Check the signal waveform Pin 88
			of IC1.

CPU is	Replace
	Q2 or
broken.
	Q3.

Table 3-8. Repair of the Control Board

Sympto	Condition Cause		Check point	Solution
m
			Check the PHASE(Pin 16 and 27) of
			IC11 and signal waveform of
			OUT(Pin 6,7, 8, and 9).
Carriage		IC2 is		Replace
		broken.		IC8.
does not	CPU does
operate	not work.
correctly.

		IC14 is	Replace
		broken.	IC11.
			Check the PHASE(Pin 7) of IC 12
			and 13, and signal waveform of
			OUT(Pin 10 and 15).
			If PHASE
		IC2 is	signal is
Abnormal	PF motor	broken.	not input,
			replace IC.
paper	does not
feed.	rotate.

IC12 &	Replace
13 are
	IC12 or 13.
broken.

Troubleshooting Repair of the Control Board 45