Principles of Operation

Table 6-7. Repairing the C076 PSB Board Assembly (Continued)

Problem

CalIS@

Checkpoint

Solution

 

 

 

 

he +5 V line is

The +35 V line is

Check the +35 V line.

Refer to the

ad.

bad.

 

items

 

described

 

 

 

 

 

 

above.

 

 

 

 

 

IC51 is bad.

Check the oscillation waveform (IC51 pin 5) and the

Replace

 

 

switching waveform (IC51 pin 8).

IC51.

Q51 or Q52 is

Check the switching waveform at Q52 emitter.

Replace

bad.

 

Q51 or

 

 

Q52.

Epson FX-870/1170

6-33