Good evening,
I need help diagnosing a Whitfield Advantage rotary knob board. I know the stove works because it has a working board I have been using as comparison. Things I know are as follows.
1. the 5.3V isolated circuit appears to be working. Jumping across output of optocouplers made no difference.
2. relay tests good and manually closing it does nothing. If I jump across MCR100 thyristor I can push start button and will close relay, but nothing works on board and relay releases when I remove jumper.
3. Jumping across P1081-1 transistor by MCR100 does nothing.
4. I have taken measurements of all semiconductors both from neutral to pins and from VSS (on each chip) to pins in both AC and DC. I have found the difference between working board and bad one is the bad one is missing approximately 15v DC in locations the working board has and I cannot figure out where that source starts.
5. I have data sheets on all components, but some I am not sure which direction power is going. For example the transistor that works the auger triac uses the collector to the triac gate, but the date sheet I have for the transistor says it is NPN.
I see many requests for a schematic so I am uploading mine. Use it with caution, because there are variations of boards and my schematic may also have errors. There are some diodes I cant see to show direction.
Ignore the capacitor directions, I made not attempt to figure out polarity.
Any advice will be much appreciated.
Thank you,
Scooter
I need help diagnosing a Whitfield Advantage rotary knob board. I know the stove works because it has a working board I have been using as comparison. Things I know are as follows.
1. the 5.3V isolated circuit appears to be working. Jumping across output of optocouplers made no difference.
2. relay tests good and manually closing it does nothing. If I jump across MCR100 thyristor I can push start button and will close relay, but nothing works on board and relay releases when I remove jumper.
3. Jumping across P1081-1 transistor by MCR100 does nothing.
4. I have taken measurements of all semiconductors both from neutral to pins and from VSS (on each chip) to pins in both AC and DC. I have found the difference between working board and bad one is the bad one is missing approximately 15v DC in locations the working board has and I cannot figure out where that source starts.
5. I have data sheets on all components, but some I am not sure which direction power is going. For example the transistor that works the auger triac uses the collector to the triac gate, but the date sheet I have for the transistor says it is NPN.
I see many requests for a schematic so I am uploading mine. Use it with caution, because there are variations of boards and my schematic may also have errors. There are some diodes I cant see to show direction.
Ignore the capacitor directions, I made not attempt to figure out polarity.
Any advice will be much appreciated.
Thank you,
Scooter
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