Hitachi RAM-50CNHZ2, Service Manual, Page: 95 / 107

– 103 –
1. Turn off the power switch of indoor unit or disconnect power plug.
2. Wait for 10 minutes or more after power is turned off and then remove electrical parts box lid. As shown below,
Apply soldering iron of 30~75W for 15 seconds or more to P1 and N1 black/white lead receptacles on system
power module to discharge voltage from smoothing capacitor.
Do not loosen or remove screws of system power module: If screw is loose, voltage will not be discharged.
3. Before operation check of ech part of circuit, remove receptable of red/gray lead connected to system power
module from diode stack.
Caution:
●
Voltage of about 360V is charged at both ends of smoothing capacitors 400
µ
F x 3.
●
High voltage (DC 360V) is also charged at screw and terminal sactions of system power module.
●
During continuity check for each circuit of electrical parts in outdoor unit is performed, to prevent
secondary trouble, disconnect red/gray wire connected to system power module (SPM2) from diode
stack. (Also be sure to perform discharging of smoothing capacitor.)
DISCHARGE PROCEDURE AND HOW TO CUT OFF POWER TO POWER CIRCUIT
W
ARNING
As shown left, apply soldering iron to metal
parts (receptacles) in sleeve corresponding
to P1 and N1 terminals of system power
module (SPM2).
RAM-50CNHZ2
GRN3
GRN1
Reactor
SPM2
Smoothing capacitor
(C501, C502, C503)
Power P.W.B
Terminal
Board (2p)
Diode Stack
(D25 VB60) Switching Power P.W.B
(For Indoor P.W.B.)
Service-switch
Control P.W.B
L 1
L 2
W
V
N 1
P 1
SMOOTHING CAPACITOR
SPM (SYSTEM POWER MODULE)
Soldering iron
Do not use soldering iron with
transformer: Doing so will blow
thermal fuse inside transformer.
Screws of system power module (SPM2) are live parts: Do not
touch them. Screw tightening torque and method are strictly
specified.
When the screw is loosened or removed once, be sure to tighten
according to the procedure shown on the right, with tightening
torque of 0.8
±
0.2 N · m.
No. 2
No. 1
No. 7 No. 6
No. 3 No. 4 No. 5