Kitchenaid Mixer Phase Control Board Problem

[e1win]

I have a strange problem with my KSM150PS which have the same phase board.

Speed 1 to 4 have the same speed. When start on "stir" motor start about 100rpm and goes in 10 sec. to about 120rpm. Governor and Control plate work as well. The Governor want to break the circuit and press on control plate. I think it must be the phase board.

On my first test i have disconnect the blue and red/white wires from control plate. So the motor must start on slowest speed but it goes to 100rpm.

The next try was change triac and diac on phase board. Same result.

Then i change the caps on phase board. Same result.

Then i change all resistors on phase board. Same result.

The measured motor power was 40.6V

Any ideas?

The resistor R5 on my phase board has 62k 1%. Can someone confirm that?

Do you repair mixer? I have the same problem
Dont know about wattage of resistors, can anybody help with it? Ksm150 325watts mixer

 

[e1win]

I have a Kitchenaid mixer that only runs on high speed. According to the service manual, this is caused by a faulty phase control board. Since I do not think I should have to spend $40 on a really simple PCB I decided to repair it. The schematic is in the service manual, but values and part numbers are not given. Here is what I was able to reverse engineer:

http://www.flickr.com/photos/85807139@N00/6344769414/

Q1 - STA06-600SW
Q2 - Unknown, suspected issue (Updated: ST MIcro DB3TG)
R1 - 120K 5%
R2 - 120K 5%
R3 - 100K 5%
R4 - 560 5%
R5 - 71.5K 1%
R6 - REMOVED FROM CIRCUIT
C1 - UNKNOWN VALUE
C2 - UNKNOWN VALUE

Q2 is what I am looking at to replace, since I already replaced Q1 and nothing changed. Q2 has a symbol I am not familiar with, it looks like a anode-anode dual zener diode, but I was thinking it may actually be a diac.

This kind of looks like a dimmer circuit used for lights, but it works by clipping the phases possibly? I am not very good with AC power circuits, so I need all the help I can get. I prefer my power with no zero crossings

Hi dear, can you help with wattage of resistors? All five resistors are 0,125 watts, or 0,25?

 

[e1win]

Can i use resistors with 1% or i must find 5%?

 

[Canrilo]

Hi! Just following the thread! Thanks all.

My kitchenaid artisan had a similar problem. Governor just disassembled and the diac was broken. I replaced both parts and now a strange behavior is appearing.

On stir speed, the motor instead of going 60rpm just "turns on" once every second, generating an intermittent sound. On higher speeds the motor sounds kind of rough. Any idea why this is happening.

Oh and I could not find the diac DB3TG, is there much difference with the DB3?

Thank you!

 

[wdancer]

According to the datasheets, the breakover voltage is 2 volts higher on the DB3TG. This may be causing the roughness. Mouser Electronics has it for $0.43

https://www.mouser.com/ProductDetai...p-_hEHP5h1K9LHont0neMoroFuXmqABhoChq0QAvD_BwE

The other issue may be that you need to adjust the control plate. I am including a link to an older service manual that shows how to adjust the control plate. Appendix B-2 gives a quick troubleshooting guide. Page 22 shows the adjustment procedure. I had to perform this on mine and it is a little difficult so only do small adjustments at a time.

https://cdn.shopify.com/s/files/1/0172/8692/2294/files/stand_mixer_service_manual_4177310_9-05.pdf