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aircon50
17-12-2014, 11:28 AM
Hi guys. Not been on for ages, and now the second post today!
An old General multi that I can't seem to find a service manual for.
External, AOH20USBV2
Interior 1, ASH12UMBD
Interior 2, ASH7UMBD

Operation LED flashes 6 times, and the fan motor in Int 2 does not run. I have checked as best possible at main connector for fan motor and have measured a peak of 170vAC across terminals 1 -3.

Could this be the fan motor or PCB?

Thanks again, Graham

Tayters
17-12-2014, 09:26 PM
Hi Graham,

Manual: http://www.aircon.ru/pbc_download/files/f1221318620.pdf
Call me Brian or Install Monkey ha ha.

6 wires on the motor. Red, white and black on CN7 are for a hall sensor to let the PCB know the rotation speed. 5V DC between red and black and a square wave output on white which varies with motor speed. You can move the motor slowly by hand and get a 5V/0V reading, think it's 4 pulses per revolution but don't quote me on that one.

CN101 are the business end of things. Supply voltage on black, start winding on yellow (capacitor on W105 and 106), neutral on white via a solid state relay to control fan speed.
You need to measure winding resistance (run: black-white, start: yellow-black) and confirm capacitor is good. If you had 170V then either motor is goosed, bearing seized or outside chance start cap faulty. Unlikely to be PCB from what you've described.

Happy Crimbo!
Andy.

aircon50
18-12-2014, 10:18 AM
Hi Andy

Thanks for the info. I already had a gut feeling that was the motor - I just needed confirmation.

Have a good Christmas and New Year!
Graham