Hitachi RAM-60QH4 Manuel De Service page 134

Discharge procedure and how to cut off power to power circuit
■ RAM-60QH4
Caution:
• Voltage of about 360V is charged at both ends of smoothing capacitor 330μF x 3.
• High voltage (DC 360V) is also charged at screw and terminal sections of system power module.
• During continuity check of each circuit of electrical parts in outdoor unit is performed, to prevent
secondary trouble, disconnect red/gray wire connected to system power module (SPM) from diode stack.
(Also be sure to perform discharging of smoothing capacitor.)
1. 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, volttage will not be discharged.
3. Before operation check of each part of circuit, remove receptacle of red/gray lead connected to system power
module from diode stack.
Screws of system power module 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.
SMOOTHING CAPACITOR
SWITCHING POWER P.W.B.
REACTOR
SELF-DIAGNOSIS LAMPS
CONTROL P.W.B.
Ｕ
Ｐ ２
N1
P
＋
L2
L1
SPM (SYSTEM POWER MODULE)
Soldering iron
SPM(SYSTEM POWER MODULE)
DIODE STACK
SERVICE SWITCH
SMOOTHING CAPACITOR
V
W
−
2P TERMINAL
BOARD
2P TERMINAL BOARD
(2 pcs.)
– 146 –
Do not use soldering iron with
transformer: Doing so will blow
thermal fuse inside transformer.
As shown left, apply soldering iron
to metal parts (receptacles) in sleeve
corresponding to P and N1 terminals
of system power module.
No.3 No.4 No.5
No.2
No.1
No.7
1 5
No.6