The oven at home was purchased around the same time this place was built, back in 1991. Ever since I purchased it in 2001 the temperature has skewed a bit from the chosen setting, but within the past couple of years it’s become noticably worse, with a ~100°F offset at the high end of the scale. This made things difficult when Danielle would want to bake bread or other things which required high temperatures.
This morning I finally got around to taking the oven apart and looking at the controller. On the board I found four failed electrolytic capacitors, all of which tested bad (infinite reading on a multimeter). Using spares from the pile of parts gathered during previous electronics projects and a lucky purchase at Radio Shack I was able to replace all four of these and get the oven going again. Initial testing shows that things are working better. With the oven set to 375°F I’m seeing the oven (measured with a Fluke multimeter and temperature probe in the air) fluctuating between ~350°F and ~380°F, which seems about right.
The failed parts are as follows: 2x 47μF 25V (C3, C13), 2x 4.7μF 35V (C9, C10). These were originally Nichicon parts, but I failed to write down the replacement brands. The 47μF replacements are Radio Shack generics, and the 4.7μF are something cheap but decent that I’d picked up from Mouser a few years ago.
Total out of pocket cost was $3.16, which is very high for two capacitors, but ordering two capacitors online isn’t worth the shipping cost, and these were available immediately. The only other cost was 4-5 hours of work disassembling the stove, the PCB stack, finding the bad capacitors, and getting replacements.
I’m glad this was fixable myself. Paying someone to fix it would have involved replacing the entire failed control module ($200+ if still available + labor). Or, if I could even find one myself, replacing the whole control module itself would have been an expensive crapshoot: what if it was something else? Simply replacing the stove would have cost near-$1k for something comparably nice.