Thermador dual wall ovens, upper oven broiler not working

[tnfarmer]

Model Number: SCED302BP/1
Brand: Other
Age: 6-10 years

Upper oven Broiler element stopped working. Ohm checked it, measured OK. Lower oven Broiler, working OK. Display touch panel (DTP) is working, responds to commands, i.e. select upper oven; broiler; a chime sounds with each touch, indicating it received the command. I decided to replace the relay board (RB). I opened the circuit breaker (CB), replaced the RB and closed the CB. The DTP did not light up, a red flashing light was displayed and some light smoke started to show up, the lower oven door was locked I opened the CB. This indicates to me the DTP in lock in the Self Cleaning mode. What other tests do I need to perform?

[Doc Ryan]

First, I would look to see where the smoke was coming from. Do any of the circuit boards or wiring show indications of burn marks?

[tnfarmer]

First, I would look to see where the smoke was coming from. Do any of the circuit boards or wiring show indications of burn marks?

"If you look at the relay board, with the P2 "ribbon" wire connector (from the display panel) to your right, look down to the lower right corner, follow the lower edge of the circuit board to the left. locate the P7 connector, from the “left” end of the connector look about 9:30 for about a inch away and there is a single black three terminal component(some kind of a solid state?) Q20 standing by its self. The smoke was coming from it. I opened the CB

I disconnect the ribbon wire from connector P2 and closed the CB. There was no more smoke! Whatever was causing the High Current to overheat Q20, stopped when I disconnected the ribbon wire. I don’t have a “complete” wiring schematic so I can’t identify the type of component that was smoking.

There is one more thing I don’t understand, but I think it could be part of the problem. The ovens had been not been used for several days when I started all of this and the “lower” oven door opened and closed normally. I removed both doors to reduce the weight while I slid the unit out enough to get to the relay board. After replaced the RB and resetting the CB and the smoke started showing up, I oppened the CB. I stopped at that point for the day. I replaced the doors and that is when I notice the lower door locked when I closed it. The next day I removed the Top door and was able to move the lock “bolt” and open the lower door. I compared the lower door lock mechanism to the top door lock mechanism and the lower one was not in its “full” reset position.

I’m thinking of using a Jumper wire to power the door lock clock motor until it gets to its reset position. Is there another way to do this from the touch panel?

[Doc Ryan]

Was the smoke coming from the same relay control board that you had just replaced? What is the part number of the control board that you replaced?

I do not know of any way to reset the door lock motor from the touch panel.

[tnfarmer]

Was the smoke coming from the same relay control board that you had just replaced? What is the part number of the control board that you replaced?

I do not know of any way to reset the door lock motor from the touch panel.

The new relay control board smoked. Its p/n is 00427199, same as the original. The p/n and other numbers on the circuit board edge are the same as the original. I’m pretty sure the board is repairable; I’m going to try anyway. The P2 connector on the new board has “locking ears” on it, which is different from the original. I had to clip them off to allow the ribbon cord end to connect up. Are you aware of that?

[Doc Ryan]

Your model number SCED302BP/1 is not coming up for me. Can you double check it please? The control board should be under warranty if you just purchased it. I would contact the place you purchased the control board from to see if they will exchange the part for you.

[tnfarmer]

Sorry about the Model number, I did a “Type O.” Try SECD302BP/01.

I got the self cleaning door lock unit, for the Lower oven, reset by unplugging the wires from it at the relay board, connector No. P9. NOTE: I also removed the wire plug connectors at P4 and P5, and P2 (the ribbon wire to the Touch panel) connector points, by doing this I have removed All power from both door lock units and the Touch panel.

I connected a jumper wire with insulated alligator clips to the L2 power terminal strip. I laded the other end of the jumper wire on a piece of cardboard to keep the tip from shorting out. I used a small finishing nail the fit in the plug P9. After resetting the CB, I clipped the loose end of the jumper wire to the nail in P9 for just 1 or 2 seconds. Yes, I said SECONDS, it moves pretty fast! Check it and keep doing it until it stops in the correct position. Look at the other door lock unit to judge where you need to stop it.

Unless while you are running the self cleaning cycle and have a power interruption before it is completed, no one should ever have to deal with this.

I have identified the component I smoked on the relay board. I expect by replacing it, the relay board should work OK. I would still like to know about the ears on connecting plug P2.

Thanks, tnfarmer

[Doc Ryan]

I would still like to know about the ears on connecting plug P2.

I am also showing that part # 00427199 is the correct one for your model oven. I am not sure why the ears on the connecting plug are different. The control board should be an exact replacement according to the manufactures information.

[tnfarmer]

I am also showing that part # 00427199 is the correct one for your model oven. I am not sure why the ears on the connecting plug are different. The control board should be an exact replacement according to the manufactures information.

Thanks, I ordered the transistor I need from Radio Shack. When I get it back together and working, I 'll make a final post.


tnfarmer