Power Transistor Check - Daikin FTKS20CVMB Service Manual

Check

5.1.9 Power Transistor Check

Check No.13
Check to make sure that the voltage between the terminal of Power transistor (+) and (-) is
Note:
approx. 0 volt before checking power transistor.
< Measuring method >
Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the
connector, press the protrusion on the connector.
Then, follow the procedure below to measure resistance between power transistor (+) and (-)
and the U, V and W terminals of the compressor connector with a multi-tester. Evaluate the
measurement results for a pass/fail judgment.
<Power transistor check>
Negative (-) terminal of
tester (positive terminal
(+) for digital tester)
Positive (+) terminal of
tester (negative terminal
(-) for digital tester)
Normal resistance
Unacceptable resistance
5.1.10 Turning Speed Pulse Input on the Outdoor Unit PCB Check
<Propeller fan motor>
Check No.15
Make sure the voltage of 270±30V is being applied.
(1) Stop the operation first and then the power off, and disconnect the connector S70.
(2) Make sure there is about DC 270 V between pins 4 and 7.
(3) With the system and the power still off, reconnect the connector S70.
(4) Make a turn of the fan motor with a hand, and make sure the pulse (0-15 V) appears twice at
If the fuse is blown out, the outdoor-unit fan may also be in trouble. Check the fan too.
If the voltage in Step (2) is not applied, it means the PCB is defective. Replace the PCB.
If the pulse in Step (4) is not available, it means the Hall IC is defective. Replace the DC fan
motor.If there are both the voltage (2) and the pulse (4), replace the PCB.
∗ Propeller fan motor : S70
144
Power transistor
pins 1 and 4.
7
6
5
4
3
2
1
UVW
(+)
UVW Power transistor
(+)
Several kΩ to several MΩ (∗)
Short (0 Ω) or open
PCB
S70
Turning speed pulse input (0-15 V)
15V
DC270V
SiENBE04-401A
Power transistor UVW
(-)
UVW Power transistor
(-)
(R2859)
Service Diagnosis