(No.YA712<Rev.002>)1-15
SECTION 5
TROUBLESHOOTING
5.1 Power Supply Section
The power cannot be turned on.
The fuse blows out.
FLOW CHART NO.1
FLOW CHART NO.2
Is normal state restored when once un
plugged
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.
(C605, D601, D602, D603, D604, Q601, Q602,
T601)
Ye s
No
Ye s
Is the fuse (F601) normal?
See FLOW CHART No.2 <The fuse blows out.>
No
Ye s
Is the AL+33V line voltage normal?
No
Check each rectifying circuit of the secondar
y
circuit and service it if def
ective.
Check the prese
nce that the pr
imary component
is leaking or shorted and ser
vice it if de
fective.
Check the presence that the rectifying diode or circuit
is shorted in each rectifying circuit of secondar
y side,
and service it if defective.
After servicing, replace the fuse.
When the output voltage fluctuates.
FLOW CHART NO.3
Does the photocoupler circuit on
the
secondary side operate normally?
No
Ye s
Check IC601, D652, Q631 and their periphery
circuit, 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 rectifying diode and the circuit
in each rectifying circuit of the secondary side
,
and service it if defective. (IC631, Q207, Q209, Q210, Q211, Q501, Q635, Q636, Q637, Q640, Q641, Q64
2, Q643,
D631, D632, D633, D638, D641, D642, D646, D
647)
Check D657, R661 and their peripher
y circuit, and
service it if defective.
AL+33V is not output.
FLOW CHART NO.5
Is approximately +34V voltage supplied to the
cathode of D638?
No
Ye s
Check C638, D638, D639 and their periphery
circuit, and service it if defective.
Check IC601, D609, D611 and their per
iphery,
circuit and service it if def
ective.
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