FUNAI LH8-M40BB - TROUBLESHOOTING GUIDE; Power and Fuse Troubleshooting

8-1 A03P0TR
TR OUBLESHOOTING
Check IC607, IC
621, D625, D
628, D630, D
631, D634,
D635, D6
36, D638 and their per
iphery
, and service it
if def
ective
.
The power cannot be turned on.
The fuse blows out.
FLOW CHART NO.1
FLOW CHART NO.2
Is normal state r
estored when once un
plugged pow
er
cord is plugged again sev
eral seconds
?
Check if there is any leak or short-circuiting on the
primary circuit component, and service it if defective.
(IC607, IC621, Q621, Q622, Q623, D609, D610,
D611, D612, T601, T602)
Yes
No
Yes
Is the fuse (F601) normal?
See FLOW CHART No.2 <The fuse blows out.>
No
Yes
Is approximately 15V voltage supplied to the cathode
of D504?
No
Check eac
h rectifying circuit of
the secondar
y circuit
and service it if de
fective
.
Check the pres
ence that the
primar
y compo
nent is
leaking or shor
ted and service it if defective
.
Check the pres
ence that the
rectifying
diode or ci
rcuit
is shorted in each r
ectifying c
ircuit of secondar
y side,
and service it if de
fective.
After ser
vicing, replace the fus
e (F601).
When the output voltage fluctuates.
FLOW CHART NO.3
Does the photocoupler circuit on
the secondar
y side
operate normally?
No
Yes
Check IC607, Q512, Q513, D505, D530 and their
periphery, and service it if defective.
When buzz sound can be heard in the vicinity of power circuit.
FLOW CHART NO.4
Check if there is an
y short-cir
cuit on the rectifyi
ng diode and
the circuit in e
ach rectifying
circuit of the
secondary side, and
service it if def
ective
. (D504, D511,
D514, D523,
D524, D525,
D539, D540, Q501, Q510, Q
517, Q518, Q521)