My Thermador UCV36AS/01 Cook'N'Vent Downdraft intake got stuck halfway in the up/down position the other day. After pressing various controls buttons on the snorkel and (unfortunately) pulling the intake by force, nothing works now and no buttons are illuminated. According to the manual, possible cause is that control button board has become disconnected.

I have taken apart the entire system including the snorkel and tried the troubleshooting steps in the service menu using the multimeter. The transformer and motor seem OK. The interference, up and down switches seem OK too, although it is puzzling why the intake got stuck to begin with. Unfortunately the service manual did not provide any troubleshooting guidance on how to test the control PCB.

There were several times that the Clean Filter Reminder button actually got illuminated, at which point the blower worked if the blower buttons were pressed. However, it appeared random and the system stopped working even though I did not seem to have touched anything. This seems to indicate that it got a loose connection somewhere. However, I could not figure out where the loose connection point was without knowing where to take measurement and what ohms or volts to expect.

Any advice and suggestion is highly appreciated.