Dim light on oven display w30400b jennair
The circuit board is for the display/touch panel. It is mounted on the back of the display panel itself and connected to the other circuit boards by two multipin connectors. When you remove the display panel (3 screws on top, 4 on the bottom) you will be able to GENTLY detach those connectors. They are low voltage and may be handled safety even when the oven is powered, but I agree that turning off the oven circuit breaker is good practice.
To remove the circuit board, GENTLY release the two black plastic tabs; the solder pads are underneath. I too used a 100 mf capacitor because no local supplier had a 68 mf hi-temp. Observe polarity; the (-) lead goes towards the center of the board (away from the edge connector.)
BTW, I had exactly the same symptoms (display goes dim, then goes out altogether.)