FUNAI LT8-M40BB - Troubleshooting Flowcharts; Troubleshooting Flowchart 1: Power On Issue; Troubleshooting Flowchart 2: Fuse Blows Out; Troubleshooting Flowchart 3: Output Voltage Fluctuates

8-1 A03P0TR
TROUBLESHOOTING
Check IC607, IC
621, D625, D628, D630, D631, D634,
D635, D636, D638 and their periphery, and service it
if defective.
The power cannot be turned on.
The fuse blows out.
FLOW CHART NO.1
FLOW CHART NO.2
Is normal state restored when once unplugged power
cord is plugged again several 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)
Ye s
No
Ye s
Is the fuse (F601) normal?
See FLOW CHART No.2 <The fuse blows out.>
No
Ye s
Is approximately 15V voltage supplied to the cathode
of D504?
No
Check each rectifying circuit of the secondar
y circuit
and service it if defective.
Check the presence that the
primary component is
leaking or shorted and service it if defective.
Check the presence that the
rectifying diode or circuit
is shorted in each r
ectifying circuit of secondary side,
and service it if de
fective.
After servicing, replace the fus
e (F601).
When the output voltage fluctuates.
FLOW CHART NO.3
Does the photocoupler circuit on
the secondary side
operate normally?
No
Ye s
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 any short-circuit on the rectifyi
ng diode and the circuit in each rectifying circuit of the secondary side, and
service it if defective. (D504, D511, D514, D523, D524, D525, D539, D540, Q501, Q510, Q517, Q518, Q521)