Hitachi RAM-52QH5, Service Manual

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Inspection method 1
Insert the power source, and check to see that the
LED is on.
Is the 25A fuse working normally?
Is the 5A fuse working normally?
Yes
Yes
Yes
Yes
No
No
No
No
LED on
LED off
The control P.W.B. is broken.
Replace the control P.W.B.
Is AC220~240V flow to the L/N terminal?
Follow "Inspecting external electrical parts" and check
the cause of the problem.
Connect a commercial-use 220-240V power source
to the L/N terminal.
Replace the broken part
and the 25A fuse.
The control power source is broken.
Replace the control P.W.B.
Is varistor 2 broken?
There is the possibility that an irregular voltage has been
flowing to the L/N terminal. Check to see that the power
source is not abnormality.
Replace the 5A fuse and varistor 2.
Check to see that varistors 1-3,
diode stacks SPM2 are not
broken.