I know I'm about 6 years late to this party, but in case there are any more Thermador CM302 or C302 ovens out there that have not already been hauled off to the landfill site I have some information to pass on that could be a big help.
I had problems with my original "Double Oven Control Display Board (#486915) in 2014 and replaced the board, then the new board started acting up 10 years later. The symptoms are similar to others reported here - an hour or so after turning off the oven the panel becomes disabled and starts beeping constantly until you shut off the breaker or until it cools off again (the panel gets hot after the oven is shut off because the ventilation fan shuts off, allowing heat to rise to the panel). Sometimes I saw error code F24, sometimes not.
Since Thermador doesn't offer replacement parts any more and I didn't want to throw out an otherwise working oven, I inspected the display board and found a lot of cold solder joints on the connector pins. A cold solder joint is a latent defect that results from an inadequate soldering process (usually not enough heat but possibly other causes). Cold solder joints are particularly susceptible to failure during temperature cycling, and often result in an intermittent problem because the joint pulls apart with thermal expansion and shorts together again when it cools and contracts. Anyway, on the largest connector, P1, I could see (under magnification) cold solder joints on 13 of the 19 pins. I re-soldered all the connectors and re-installed the board and all is well now.
Out of curiosity, I pulled out the original board that I had replaced 10 years ago and indeed it had a lot of cold solder joints as well. That board exhibited different symptoms, but most likely that's just because the joint that failed first was not on the same pin that failed first on the newer board.
Unfortunately it seems the soldering process was not good and a lot of boards were probably manufactured with the same latent defect (my boards were 10 years apart and were different revisions but both had the same defective joints). Depending which joints go open-circuit first, this could result in different failure symptoms.
It's a real shame that Thermador did not figure this out in their repair and/or customer service process, when I was able to do so at my kitchen table. Surely if they had, they would have swapped out and reworked the boards that were giving so many customers problems. Had they done that they could have built some brand loyalty from customers who felt well taken care of. Instead I think there are a lot of "I'll never buy another Thermador" people out there (myself included).
If you're having problems and you haven't yet dumped your oven at the landfill and shelled out thousands for a new one, try removing this board and just get a friend-of-a-friend with reasonable electronics soldering skills to re-flow the solder joints on the connectors (about a 5 minute job).
I'd like to post some photos but it doesn't look like I can post images from my computer. But I'll keep them around in case anyone's interested. They show some excellent examples of bad workmanship. Also, thanks to Appliance Parts Pros for making this forum available - I only wish I could have found and reported this issue sooner.
Let's see if this photo works:
https://ibb.co/NNXsW1cEdited by user Wednesday, January 24, 2024 5:16:20 PM(UTC)
| Reason: typo