Discharging Capacitors; Cutting Off Power Supplied To The Power Circuit - Hitachi RAS-25CNH1 Service Manual

The smoothing capacit-
ors (1,000µF) are
charged to about
340V. Don't forget to
discharge them before
attempting access to
electric parts.
Before checking
electric parts of the
outdoor unit,
disconnect the power
line of the power circuit
to cut off supply power.
This is necessary to
protect the parts.

DISCHARGING CAPACITORS

1. Turn off the indoor unit's power switch or unplug the power cord, and wait
for a minute or so.
2. Open the cover of the electric parts compartment. Discharge electricity
from smoothing capacitors (1,000
soldering iron of 30
Continue discharging for more than 15 seconds.
Both ends
of R802
DC voltmeter or tester
(same as in case of oscilloscope)

CUTTING OFF POWER SUPPLIED TO THE POWER CIRCUIT

Remove the receptacle of the gray / brown lead wire connected to the smoothing
capacitor from control P.W.B. before performing operation check of each point in the
circuit.
When checking conductivity at each point of circuit in electrical parts of outdoor unit,
to prevent secondary trouble, disconnect gray / black lead wire connected to
smoothing capacitor from control P.W.b. in order to shut off power to the power
module before checking. Connect (+) side of C516 and 5V using clip at this time. If
this is not done, there will be no drive output. (LED310 blinking 10 times mode is
set.)
µ
F) by connecting the leads of a
_
75W to the terminals provided for this purpose.
F-Cabel ( ∅ 2, single lead)
Plug
– 92 –
_
Soldering iron of 30 75W
Do not use a soldering
iron with built-in
transformer : the fuse
built in the transformer
would blow out.