Daikin RTSQ20PY1 Service Manual page 352

Troubleshooting (Heat Reclaim Ventilation)
CHECK 4
Power Transistor Check
Perform the following procedures prior to check.
(1) Power Off.
(2) Remove all the wiring connected to the PCB where power transistors are mounted on.
[Preparation]
· Tester
[Point of Measurement and Judgement Criteria]
· Measure the resistance value using a tester at each point of measurement below, 10 minutes later after power OFF.
To use analog tester:
Measurement in the resistance value mode in the range of
multiplying 1kΩ.
Point of Measurement
No.
+ –
1 P2 U
2 P2 V
3 P2 W
4 U P2
5 V P2
15kΩ and
6 W P2
above
7 N3 U
(including ∞)
8 N3 V
9 N3 W
10 U N3
11 V N3
12 W N3
[PCB and Circuit Diagram]
341
Judgement
Remarks
Criteria
2 ~ 15kΩ
Due to condenser
charge and so on,
resistance
measurement may
require some time.
2 ~ 15kΩ
J1
J2
J3
* Preparing a tester in the analog system is recommended.
A tester in the digital system with diode check function will
be usable.
To use digital tester:
Measurement is executed in the diode check mode. (
Point of Measurement
No.
+
1 P2
2 P2
3 P2
4 U
5 V
6 W
7 N3
8 N3
9 N3
10 U
11 V
12 W
P1 P3
P1
DM
X10A K2
J1
L1
J2
L2
L3
J3
Judgement
Remarks
Criteria
–
U
Due to condenser charge and
1.2V and over so on, resistance measurement
V
may require some time.
W
P2
P2
P2
0.3 ~ 0.7V
U
V
W
N3
Due to condenser charge and
1.2V and over so on, resistance measurement
N3
may require some time.
N3
W
V
N3 U
P2 P3
IGBT
N3
U V W
X11A
Troubleshooting
SiBE31-801_C
)