Hitachi RAC-25FXA RAC25FXA Manual De Usuario
Los códigos de productos
RAC25FXA
14-8
14.1.11 MONO SPLIT RAD-50/60/70PPA / RAC-50/60/70DPA
Warning
Remember that voltage of 155-170V is applied to the 0V line
on the P.W.B. or the like as shown in the diagram below
on the P.W.B. or the like as shown in the diagram below
Warning
When using an oscilloscope, never ground it. Don’t forget that
high voltage as noted in the left figure may apply to the
oscilloscope.
high voltage as noted in the left figure may apply to the
oscilloscope.
Other Cautions
1) Cautions concerning for short circuit in
servicing.
a) Use due caution to prevent short circuit in
a) Use due caution to prevent short circuit in
servicing. Short circuit wll immediately
open the ICP.
open the ICP.
b) If the ICP is open, remove the causes and
replace the ICP. If the remedy is improper,
the ICP maybe blown again.
the ICP maybe blown again.
2) The CN3 (power supply) and CN10 (fan motor)
are the connectors with lock mechanism. Press
the lock with your fingers to unlock and remove
the connector.
the lock with your fingers to unlock and remove
the connector.
3) When checking the voltage and waveform, do
not connect the probes to the forbidden areas
shown below. Touching them may cause the
ICP1 blowout and Q11 failure.
shown below. Touching them may cause the
ICP1 blowout and Q11 failure.
The Q11 is a MOS-FET and its gate terminal is
high impedance. When a probe such as
multimeter is contacted with gate Ⓖ, the Q11
may have continuous ON state to supply
overcurrent in the circuit causing the ICP1 blow
out and Q111 failure.
high impedance. When a probe such as
multimeter is contacted with gate Ⓖ, the Q11
may have continuous ON state to supply
overcurrent in the circuit causing the ICP1 blow
out and Q111 failure.
When checking the switching waveform of
Q111, set the source Ⓢ to the base and
measure the gate Ⓖ and drain Ⓓ.
Q111, set the source Ⓢ to the base and
measure the gate Ⓖ and drain Ⓓ.
4) During power feeding to the P.W.B., do not remove and insert the CN10 (fan motor connector). Failure to do so may cause
overcurrent to the fan motor and P.W.B.s (microcomputer, IC and the like) and a failure may occur. To remove or insert the
CN10, be sure to shut off the power.
CN10, be sure to shut off the power.
ICP2
ICP1
12V Power
Circuit
20V
Zener diode
ZD121
5V
Power
Circuit
12V line
5V line
35Vlne
Indoor unit fan motor
Press here
Unlock
Lock
35V line
ICP1
0V
Q111
OK
OK
G
S D
S: Source
D: Drain
G: Gate
D: Drain
G: Gate
Forbidden area (GateⒼ to 0V)
IC111
0V
Main P.W.B.
Power source
System Power module 2
Indoor units
Control
P.W.B.
Compressor
C
D
D
DC35V
0V
(0V)
ⓑ
ⓐ
ACT
m
o
d
u
le
P
o
w
e
r m
o
d
u
le
Across ⓐ-ⓑ (0V line) approx 260~360V
Across ⓐ-ground approx 155~170V
Across ⓑ (0V line)-ground approx 155~170V
Across ⓐ-ground approx 155~170V
Across ⓑ (0V line)-ground approx 155~170V
Outdoor unit
P.W.B.
P.W.B.
Always keep your
hands and metallic
things away from
the oscilloscope
hands and metallic
things away from
the oscilloscope
DANGER!
Don’t install
the ground
line
the ground
line