Hitachi RAS-50WX8 Service Manual page 84

B
R24
DC current (Id)
detection resistor
Since current flows at point
waveform as shown in Fig. 3-3. Since current at point
conditioner, input current is controlled by using DC current (Id) detection resistor.
<Reference>
If power module is detective, self diagnosis lamps on the main P.W.B. may indicate as shown below:
Smoothing Capacitors
SPM2 Diode Stack
CN14
CN8 CN7
CN15
WHT
CN5 CN10 CN9
Reactor Service
Switch
Fig. 3-5
Simplified check of power module (Lighting mode when operated with compressor leads disconnected)
(1) Disconnect connector of 3-pole (WHT, YEL, RED) lead wire connecting to compressor located at the lower
part of electric parts box.
(2) Set to compressor operation state (other than FAN mode) and press Start/stop switch of remote control.
(3) If normal operation continues for more than 1 minute (LD303 lights), power module is considered normal.
Refer to other item (troubleshooting on page 200) for independent checking of power module.
System Power module 2
320-360V
U
U
Fig. 3-4 Power module circuit (U + is ON, V - is ON)
only when U + transistor is ON, the current waveform at point
N
YEL
BLU
GRN2
RED
BRN
CN2
RED BLK
GRN1 WHT
Terminal Boards
LD301 P.W.B. (Main)
LD302
LD303
Self Diagnosis Lamps
W
V
V W
is approximately proportional to the input current of the air
Table 3-1
Self-diagnosis
Ip (peak current cut)
Abnormal low speed
rotation
Switching failure
– 124 –
DC compressor
motor
A U coil
U
V
W
V coil
becomes intermittent
Self-diagnosis lamp
and mode
LD301
LD301
LD301
W coil
Blinks 2
times
Blinks 3
times
Blinks 4
times