8-1
A0CN0TR
TROUBLESHOOTING
Check IC605, D603, D606 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.
(IC605, Q601, Q602, D602, D604, D605, D607,
T601, R602)
Yes
No
Yes
Is the fuse (F601) normal?
See FLOW CHART No.2 <The fuse blows out.>
No
Yes
Is approximately 32V voltage supplied to the cathode
of D618?
No
Check each rectifying circuit of the secondary 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 rectifying circuit of secondary side,
and service it if defective.
After servicing, replace the fuse (F601).
When the output voltage fluctuates.
FLOW CHART NO.3
Does the photocoupler circuit on the secondary side
operate normally?
No
Yes
Check IC605, Q603, D615, D623, D628 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 rectifying diode and the circuit in each rectifying circuit of the secondary side, and
service it if defective. (D612, D616, D618, D622, D637, Q605, Q606, Q609, Q611, Q615, Q616)
Summary of Contents for LT850-M22 - SERVICE
Page 13: ...4 2 A0C72_73DC 2 Rear Cabinet 1 Stand Assembly S 3 S 2 S 2 S 2 S 2 S 2 S 4 S 5 S 1 Fig D1...
Page 36: ...10 4 A0C70SCM2 Main 2 Schematic Diagram...
Page 37: ...10 5 A0C70SCM3 Main 3 Schematic Diagram...
Page 38: ...10 6 A0C70SCM4 Main 4 Schematic Diagram...
Page 39: ...10 7 A0C70SCF Function Junction Schematic Diagram...
Page 40: ...10 8 Jack Schematic Diagram A0C70SCJ...
Page 75: ...LT850 M22 LT851 M22 A0C70EP A0C71EP 2010 06 03...
