Power Transistor Check - Daikin RXYQ-TA Series Service Manual

Check
4.4

Power Transistor Check

CHECK 4
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
Multimeter
Point of Measurement and Judgement Criteria
Turn OFF the power supply. Then, after a lapse of 10 minutes or more, make measurement of
resistance.
When using the analog type of multimeter,
make measurement in resistance
measurement mode in the x1kΩ range.
No.
PCB and Circuit Diagram
J1
J2
J3
295
Measuring
Judgement
point
Criteria
+ –
1 P2 U
2 P2 V 2 ~ 15 kΩ
3 P2 W
4 U P2
5 V P2
15 kΩ and
6 W P2
more
7 N3 U
(including )
8 N3 V
9 N3 W
10 U N3
11 V N3 2 ~ 15 kΩ
12 W N3
U V
N3
P1 P3
∗ Prepare the analog type of multimeter.
For the digital type of multimeter, those with
diode check function are available for the
checking.
When using the digital type of multimeter,
make measurement in diode check mode
(
Remarks No.
1
2
3
4
5
Due to condenser
charge and so on,
6
resistance
7
measurement may
require some time.
8
9
10
11
12
X10A K2
L1
L2
L3
Since the appearance of PCB shown in this outline drawing is different from
the actual appearance, use it as a reference drawing.
W
)
Measuring
Judgement
point
Criteria
+ –
Due to condenser
P2 U
charge and so on,
1.2 V and
P2 V
resistance
more
measurement may
P2 W
require some time.
U P2
V P2
W P2
0.3 ~ 0.7 V
N3 U
N3 V
N3 W
Due to condenser
U N3
charge and so on,
1.2 V and
V N3
resistance
more
measurement may
W N3
require some time.
P1 P2 P3
DM
J1
J2
J3
N3
SiUS341615E
Remarks
IGBT
U V W
X11A
Service Diagnosis