Service manual

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REV.-A

Table

5-4.

Repairing the BOARD ASSEMBLY, C076

PSB/PSE

(Continued)

Problem

rhe+5Vlineisdead.

Cause

rhe

+35 V line is

~ead.

C51

is dead.

251

or

Q52

is

iead.

Checkpoint

;heck

the +35 V line.

:heck

the oscillation waveform

(IC51

pin 5) and the

switching waveform

(IC51

pin 8).

I

I I

I I

I

I

I I

+

I

II

Ill

I

II

II

II

I

1 1 1

I

1

I

CH1=2V CH2=20V

TlME=20ps

Check the switching waveform at

Q52

emitter.

-F

11111+1111

L

II

CH1=20V

*

TlME=20~s

1

1 1

I [

I

1

Solution

{efer

to tht

terns

iescribed

]bove.

{eplace

C51.

Replace

D51

or

D52.

5-13