A Microwave Repair Even Mechanical Keyboard Fans Will Love

Microwave oven design and manufacturing have been optimized to the point where the once-expensive appliances are now nearly disposable. Despite the economics, though, some people can’t resist fixing stuff, especially when you get a chance to do it in style. Thus we present this microwave repair with its wholly unnecessary yet fabulous adornments.

The beginning of the end for [dekuNukem]’s dirt cheap second-hand microwave started where many of the appliances begin to fail first — the membrane keyboard. Unable to press the buttons reliably anymore, [dekuNukem] worked out the original keypad’s matrix wiring arrangement and whipped up a little keypad from some pushbutton switches and a scrap of perfboard. Wired into the main PCB, it was an effective and cheap solution, if a bit on the artless side.

To perk things up a bit, [dekuNukem] turned to duckyPad, a hot-swappable macropad with mechanical switches and, of course, RGB LEDs. Things got interesting from here; since duckyPad outputs serial data, an adapater was needed inside the microwave. An STM32 microcontroller and a pair of ADG714 analog switches did the trick, with power pulled from the original PCB.

The finished repair is pretty flashy, and [dekuNukem] now has the only microwave in the world with a clicky keypad. And what’s more, it works.

32 thoughts on “A Microwave Repair Even Mechanical Keyboard Fans Will Love

      1. a little off topic, but it’s because it’s hard to talk/text on a cellphone and shift gears at the same time, although it can be done if the driver can hold the steering wheel with their leg…..seen it being done !

        1. You can also ask a passenger sitting next to you to shift your gear. You still operate the clutch just instead of using your right hand to shift gear you ask a passenger. This way you can still steer with one hand while feeding yourself dinner with the other hand!

    1. Marketing featuritis, I suspect. That said, when we shopped at Curry’s PC World for a microwave to put in our UK flat, only the *very* cheapest of the microwaves included a rotary encoder.

    2. I looked at the ones with a rotary encoder and found it to be clumsy for elementary use.

      The best button on mine is the “add 30 seconds” button which also starts the cooking. For reheating leftovers that’s practically the only button I use.

    3. I have a microwave like that. I used to think it was neat.

      Then I decided it was crap, because it was simply more cumbersome than the keypad to do anything with it. Not worth buying a new microwave for, especially considering the existing one is an inverter, but still. Would much rather have the keypad.

    4. Here is South Africa, the “extreme” budget microwave ovens have start / stop buttons and rotary encoders, but all low / / mid range microwave ovens have keyboards.
      The high range ones have keyboards too, but since you can’t use them without reading the manual, they’re useless for all practical purposes.

    5. Let’s disagree on that. I’m not un US yet my microwave got numpad and display. I’d say numpad are quite lame cost-optimized “flat” buttons, btw. Which aren’t fun at all, their only “advantage” they cost almost nothing. But honestly, I’d gladly pay $1 or even $5 extra for nice, pleasant to press buttons instead of this cost-optimized crap.

      Btw, this repair looks cool. A bit too “acidic” – but orders of magnitude better than crap most microwave ovens got from factory any day.

  1. Over the last 30 years, I fixed 100’s of uWaves… magnetron, shorted HV caps, diodes, turntable motors, and the covers over the magnetron output, which can be bought by the sheet and cut to fit… but the keyboards were the hardest to obtain, so I always recommended to any costumer to “level” the usage of the keypad, IE, don’t use the same keys every time ….60 seconds is close to 59 seconds,etc,

    1. Yes, the transformer has a rated power of 2kV and ~1kW, for a short time oeprartion it can output much more: Drawing an arc with two secondary series connected MOTs pulls 35A at 230V out of the wall socket .So even one of the transformers has roughly the equivalent output of an electric chair.

      1. The old uWave HV cap had an internal bleeder resistor, the new owns don’t have them, to make them “Greener” , I fried my best Fluke testing that one . Thankfully most uWaves have a schematic inside. If you have a way to discharge the HV cap ,a screwdriver can do it,lol

  2. Nice. Not the only one with a clicky keyboard, there may be one in landfill somewhere. My dad did this 30 years ago after the liquid membrane paint wasn’t up to the job. Yes even then they had crappy keypads.

  3. I miss the old microwaves with the mechanical timers!

    Disable the magnetron, put a couple UV lamps in there, and they make a wonderful curing station for SLA 3D prints!

    (Yea, you could do that to one with digital controls, too, but it seems so… inelegant.)

  4. The optimal microwave has two dials and absolutely NOTHING else.
    1. dial sets time, by winding a mechanical timer.
    2. dial sets effect by adjusting the discharge resistance, to control how often power is applied to the magnetron.

    All other currently implemented solutions are wrong.

    1. That’s a rather sweeping statement. I’ve used both types of microwaves over the last 45 years. Personally, I like being able to reheat my coffee to just the right temperature every time, with a touch of a single “30 sec” button. And since every microwave I’ve ever had cooks the edges of meat during the “defrost” cycle, it’s convenient to be able to get precisely and reproducibly 1/10 power for 30 minutes for a slower but proper defrost. Different strokes for different folks, and all that.

  5. This repair is on my mind as we have an 11-year-old microwave whose keypad is showing wear. It’s the kind of appliance that you hand on the wall above the stove, and has an exhaust fan so we routed ductwork through the cabinet above it… which makes me apprehensive about having to replace it as I’m sure that ductwork will not be uniformed from one to the next.

    The clicky keyboard on this one is very satisfying, but not ideal the long-run of keeping everything in the kitchen clean (think of frying bacon on the stove below and then trying to clean grease off the keycaps). However, patching into the key matrix is an interesting tidbit. Would be interesting to replace the membrane keyboard with a PCB that has capacitive touch pads on it. Filing this one one away as viable future options.

    Is there anything else that wears out on these appliances that I should have in mind?

    1. I could be wrong, but all the above stove uWaves i’ve worked on /replaced had a standard output vent, depending on the value of the Dollar, last i heard was they were around 800$…..
      There are only maybe 20-30 parts in any uWave, most are available on Fleabay or other appliance wholesalers

      1. To answer your question, for a uWave of that age, if you have cats or dawgs, the magnetron is surely clogged with hair and dust, but that will require pulling it down, a T25 torx bit, and removing the fan enclosure to access the maggy

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