Principles of Operation

Table 6-8. Repairing the C094 MAIN Board Assembly (Continued)

Problem

Symptom

Cause

Checkpoint

Solution

Abnormal

The CPU

The CPU is

Check the oscillator signal (IC2Cl pin 27 or

If the signal is

operation at

does not

defective.

pin 28).

not correct,

power on.

operate

 

 

replace

 

properly.

 

 

IC2Cl.

 

 

 

 

Otherwise,

 

 

 

 

replace CRl.

Carriage

The

IC6 is

Check the input signal (pin 5) and the output

Replace IC6.

operation

carriage

defective.

waveform (pin, 8).

 

abnormal.

does not

 

 

 

 

operate at

 

 

 

 

all.

 

 

 

Epson FX-870/1170

6-35