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+32
V
Regulator
1 .
U
sing t h e Scope,
m
eas ure t hat t here is α waveform across
T
401D
1 . -32
V
regul ato r
2 . +5 .1 V reg ul ator
3 . +12 V regul ator
4 . -12
V
reg ul ator
-32
V
R
eg
u
lator
P
roceed as
f
ollows :
1 .
U
sin g α Vol t m eter
m
eas ure voltage bet ween L405 and L 406 . Th is
sh ould
b
e greater t han 32 V
2 . C heck Z en er diodes Ζ406
a
nd Ζ411
3 . C heck inductors L 405, L40~6,
L
409 and L410
f
or o pen-c ircuit
4 . C heck electroly tic capacitors C E435, CE436 and C E440
f
or
s h ort-c ircuit
+5.1
V R
eg
u
lator
P roceed as
f
oll ow s :
2 . C h eck Zener diode Ζ409
+12
V R
eg
u
lator
P
roceed as follows:
2 . C h eck
C
R 431 (ro ugh D C - Scop e or M eter)
5 . C hec k Q406, Ζ405, Ζ410 and assoc iated components
HP 811 OA Se
r
vice Guide
3 .
U
sing α Vol t meter,
m
eas ure vol tage
b
et ween L403 and L404 . Thi s
sh ould
b
e in th e region
o
f +55 to +60 V DC (no load conn ected)
4 .
U
s ing α Volt meter,
m
eas ur e vol tage across Ζ404 . Thi s should
b
e
+15 V D C, with or wit hout load
6 . If th ere i s α
D
C voltage at Ζ405
a
n ode, check L 407 and L408
To fin d o ut whi ch other reg ulators are not workin g,
m
eas ure
regul ator input wa v efor m
a
nd output voltages in th e
f
ollowing order :
1 .
U
sing α Voltm eter
m
eas u re vo ltage bet ween L415 an d
L
416 . Thi s
sh o ul d be greater than 5.1
V
3 . C h eck ind u ctors L415, L 41 .6, and L420
f
or op en-circui t
4 . Check el ectroly ti c capaci tors C E468, C E469, C470, C473 and
CE474
f
or sh ort-c ircuit
5 . Check
S
upp ressor XS405
1 .
U
s in g α
V
ol tmeter
m
eas ure v o ltage
b
etw een L 411 an d
L
412 . Thi s
sh ould
b
e greater than 12 V
2 . C hec k Z en er diode Ζ407
3 . Ch eck in du ctors L 411,
L
412,
L
423 and
L
424
f
or op en-ci rc uit
4 . Ch eck el ectrolyt ic capacitors C E460, C E461 and
C
E463
f
or
s hort-circuit
Tr
o
ub
les
h
ooti
n
g 4-13
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