Hitachi RAC-50YH7, Service Manual

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CHECKING THE INDOOR/OUTDOOR UNIT ELECTRICAL PARTS AND REFRIGERATING CYCLE
Does the timer lamp on the indoor unit blink?
Is the compressor in the outdoor unit operating?
Does the operation lamp on the indoor unit
start to light or blink?
Remove the outdoor unit cover and
electrical parts cover, and check
self-diagnosis lamp LD301
Does LD301 blink one time ?
* Repeats 0.25-second on and
2-second off.
Blinking other than
one time One-time blinking
Yes
Yes
Yes
Yes No
No
No
Normal
No
No
Timer
lamp
Press the service switch for 1 sec.
Does the compressor operate?
(After checking, be sure to press
the service switch to stop the
operation).
Check the refrigerating cycle.
Check the outdoor electrical parts. Check the indoor electrical parts.
Check to see whether the F-
cable is connected incorrectly
or disconnected
See Out door unit self-diagnosis lamp
lighting mode .
See Troubleshooting when the timer lamp
blinks .
Is approx. DC 33 to 37V being generated? Is the
polarity correct?
Remove the terminal cover and check the voltage
between terminal (C) and terminal (D)
Terminal C
Terminal A
Terminal B
(+35V)
Terminal D
(0V)
SMOOTHING
CAPACITORS
SYSTEM POWER
MODULE (SPM2)
LD301
LD302
LD303
LD304
SERVICE SWITCH
MAIN P.W.B.
POWER P.W.B.