Hitachi RAS-10JH1 Service Manual page 57

Since current flows at point B only when U
point B becomes intermittent waveform as shown in Fig.4-3. Since current at point B is approximately
proportional to the input current of the air conditioner, input current is controlled by using DC current (Id)
detection resistor.
<Reference>
If power module is defected, self diagnosis lamps on the MAIN P.W.B. may indicate as shown below:
POWER P.W.B.
MAIN P.W.B.
LD301
LD302
Ｒ Ｅ Ｄ
LD303
Fig. 4-4 Power module circuit (U
+
transistor and V
Fig. 4-5
+ –
is OFF, V is ON)
–
transistor are ON, the current waveform at
Table 4-1
Self-diagnosis
Ip (peak current cut)
Abnormal low speed
rotation
Switching incomplete
- 55 -
Self-diagnosis lamp
and mode
Blinks 2
LD301
times
Blinks 3
LD301
times
Blinks 4
LD301
times