Hitachi RAF-50FX8 Service Manual page 146

Procedures for Electrical Discharge and How to Stop Energizing the Power Circuit
Notes
Voltage of approximately 320-360V is charged on the both ends of 3 smoothing capacitors 330μF. High voltage
(DC320-360V) is charged on the screws and terminals of SPM2.
When checking the energizing to each part of the circuits of outdoor electrical devices, disconnect the red and gray wires
which are connected from diode stack to system power module (SPM2) to prevent secondary malfunction. (Make sure to
discharge the smoothing capacitor.)
1. Switch OFF the power or unplug the power of the indoor unit.
2. After switching OFF the power, wait for 10 minutes or longer, then apply a soldering iron of 30-75W on P1 and N1
terminals on the system power module to discharge the charged voltage on the smoothing capacitor. Do not loosen or
remove the screws of SPM. If the screws are loosened, discharging cannot be performed.
3. To perform operation check of each part of the circuit, remove the receptacle of the red and gray lead wires which are
connected from diode stack to system power module.
Ｕ
Ｐ ２
N1
P1
SPM2 (system power module)
Screws on SPM are energized. Be careful not to touch with hands. Its
tightening torque and tightening method are strictly defined. Once the screw
is loosened or removed, the screw must be tightened at tightening torque of
±0.2 N ・ m following the procedures shown in the drawing on the right.
0.8
SPM2
WARNING
Smoothing capacitor
V
W
−
+
L1
L2
Soldering iron
Smoothing capacitors
Diode stack
Ｃ Ｎ １ ４
Ｃ Ｎ ８ Ｃ Ｎ ７
Ｃ Ｎ ５ Ｃ Ｎ １ ０ Ｃ Ｎ ９
Reactor
Service
switch
Do not use soldering iron with
transformer as the temperature fuse
inside the transformer can blow.
Apply soldering iron on P1 and N1 terminal as shown
in the drawing on the left to discharge the charged
voltage on the smoothing capacitor.
Ｙ Ｅ Ｌ
Ｂ Ｌ Ｕ
Ｇ Ｒ Ｎ ２
Ｒ Ｅ Ｄ
Ｂ Ｒ Ｎ
Ｃ Ｎ ２
Ｒ Ｅ Ｄ
Ｇ Ｒ Ｎ １ Ｂ Ｌ Ｋ
ＷＨ Ｔ
Ｃ Ｎ １ ５
ＷＨ Ｔ
LD301
P.W.B. (main)
LD302
LD303
Self diagnosis lamps
– 166 –
4 5
3
2
6
1 7
Ｎ
Terminal boards