Stop the bleeping beeping!

We have an inexpensive window air conditioner on Soggy Paws. It is a Maytag, but from pictures of other similarly-priced units on the web, it could be any low-end brand.

It is a pretty nice reliable unit for a window a/c.

It has an electronic control panel with a timer, a digital temperature setting, and a fan/hi/low setting. One of it's 'features' is a loud beep emitted when any button is pushed on the control panel. Others on the internet complained of this when the unit is working properly, just because changing a setting in the middle of the night makes a beep loud enough to wake the family.

Sometime in the last few months, the a/c started beeping on its own. Watching it, it looked as if a ghost was pushing the timer button on and off at random times. It started out happening only occasionally and gradually increased in frequency. We could not correlate what might be making it beep. Dave thinks the thing came with a remote (which can't be found) and one theory was RFI from something else was putting it in and out of timer mode.

So we played with computer and cell phone chargers and even asked the neighbors in the boat next door what they were doing when it would beep.

As it started to increase in frequency, we started unplugging the durned thing during the day. However, there was no way we could silence it at night.

Finally, after one night when it persisted in beeping on and off at 5 second intervals at 4am... I requested that Dave take a look at it.

Over the next 3 days, he patiently (and carefully) dismantled the A/C, trying one thing and another. First starting with cleaning and re-seating all the contacts we could get to. Then leaving the control panel unsecured... to try to eliminate heat and pressure issues. Next was de-soldering and removing the legs of a transistor (I think) that looked like it was controlling the beeper. We ended up finally taking the whole darned thing off. The a/c still worked but the beeping continued.

Next was de-soldering removing what we thought was the beeper (a small round black thing). The a/c STILL worked but the beeping continued. Have no idea what those parts were, but he did put them back on.

Then we unplugged some contacts to a big toroid looking thing. Nope, not that. Hmmm...

Finally, he went one layer deeper into the a/c, opening up another area behind the control panel. Then we plugged it back in and listened for another beep (it's not predictable--might take 5 minutes, might take 5 hours). Still beeped, but... alas, the beeping was not coming from the control panel we had spent 3 days fooling around with, but from something BEHIND the control panel.

So, Dave removed one more thing. And yup, that was it.

YAY FOR DAVE!!!! NO MORE BLEEPING BEEPING!!!

Sorry, didn't think to take pics of this operation.