Component Repair Information (For Dealers Outside The U.s.); Repairing The C076 Psb Board Assembly - Epson FX-870 Service Manual

Component Repair Information (for Dealers Outside the U.S.)

This portion of the manual provides additional information for servicers outside the U.S. who need
to make repairs to components on the circuit boards. (U.S. service technicians can ignore these
pages.)

Repairing the C076 PSB Board Assembly

This section gives instructions for repairing the C076 PSB board assembly. It describes various
problems, likely causes, checkpoints, and solutions. The checkpoint column provides proper
waveforms, resistance values, and other information for each component of the C076 PSB.
The OPERATE button on the control panel only turns the secondary power circuit on or off, so
the primary power circuit is live as long as the printer is connected to an AC power outlet.
Do not touch the heat sink attached to the FET (Ql) when the printer is powered.
Table 6-7. Repairing the C076 PSB Board Assembly
Problem
The +35 V line is Diode bridge DBl
Sad.
The transformer
coils are open.
Epson FX-870/1170
WARNING
Cause
Measure the DC voltage between pins 3 and 4 of
b a d .
Measure the resistance of the Tl transformer coils
at pins 3-2, 5-4, 1 O-l 1, and 11-9.
Checkpoint
Principles of Operation
Solution