– 77 –
CAUTION
A high voltage (equivalent to the supply voltage) is also energized to ground through the sensors,
PMV and other low-voltage circuits.
The sensor leads and other wires are covered with insulated tubes for protection.
Nevertheless, care must be taken to ensure that these wires are not pinched.
Take sufficient care to avoid directly touching any of the circuit parts without first turning off the
power.
At times such as when the circuit board is to be replaced, place the circuit board assembly in a
vertical position.
Laying the board flat on an electrically conductive object (such as the top panel of the air conditioner's outdoor unit)
while a charge is still retained by the electrolytic capacitors of the inverter's main circuit may cause short-
circuiting between the electrolytic capacitors and secondary circuit components and result in damage to the
components.
Sensor leads
Do NOT lay the circuit board assembly flat.
K
Precautions when inspecting the control section of the outdoor unit
NOTE :
A large-capacity electrolytic capacitor is used in the outdoor unit controller (inverter).
Therefore, if the power supply is turned off, charge (charging voltage DC280 to 380V) remains and dis-
charging takes a lot of time.
After turning off the power source, if touching the charging section before discharging, an electrical shock
may be caused. Discharge the electrolytic capacitor completely by using soldering iron, etc.
< Discharging method >
1. Remove the inverter cover (plating) by opening four mounting claws.
2. As shown below, connect the discharge resistance (approx. 100
Ω
40W) or plug of the soldering iron to
voltage b – terminals of the C14 (“CAUTION HIGH VOLTAGE” is indicated.) electrolytic capacitor
(500
μ
F/400V) on P.C. board, and then perform discharging.
Fig. 11-2
Discharging position
(Discharging period
10 seconds or more)
Plug of
soldering iron
Inverter cover
P. C. board
(Soldered surface)
Fig. 11-3
