Hitachi RAS-50WX8 Service Manual page 149

［No operation or abnomal operation］
Is 220-230V AC being
supplied to terminal L and N?
Yes
No
Is the 25A fuse normal?
Is the power circuit normal?
See the description on
power circuit for details.
Yes
No
Is the 5V being generated
between Pin ④ (0V) and pin
③ (5V)at CN 18 (test pin)?
Yes
Operate the outdoor unit
according to the instruction
"How to operate the outdoor
unit independently"
How did the self-diagnosis
lamp (LD301) light?
If the 25A fuse has blown,
be aware that other parts
may also be defective
(mainly, varister 2, diode
stack, smoothing capactiors,
power module, etc.).
No
Yes
Is the switching power circuit OK?
Has the 3A fuse blown?
See the self-diagnosis lamp
lighting mode.
Replace any defective parts.
Check to see whether the
connected C and D cable
correctly? If reversed, correct the
cable connection.
Replace any defective parts.
If the 3A fuse has blown, the
transformer, R906, etc. may
also be defective.