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OT: troubleshooting "noise" problems....

So my almost 40 year old Panasonic microwave oven (mid eighties) is still working perfectly. Talk about build quality!

 

To my surprise, it suddenly was making a faint buzzing sound when turned off. Wow, that does not sound good! Is something shorted out and arching?

 

  • Measured the power consumption when off and it was normal (~1W to power the display and clock)
  • Decided to open it up (Yes, I am fully aware of the dangerous voltages present even when unplugged, so I was careful. There are some high voltage capacitors!).
  • Inspecting the circuit board, the noise was apparently coming from some buzzer there. (see picture)
  • I blew some compressed air at it and all noise disappeared.
  • Better than new again!!!

 

 

altenbach_1-1680723793052.png

 

Message 1 of 10
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@altenbach wrote:
  • Decided to open it up (Yes, I am fully aware of the dangerous voltages present even when unplugged, so I was careful. There are some high voltage capacitors!).

I'm sure you are aware, but when opening a microwave the high voltage isn't the only danger. I guess 'don't try this at home' applies.

 

I wander if the European 'right to repair' will bring some of the product quality back. It sure sounds good in theory, but commerce usually find ways out of it.

Message 2 of 10
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Reminds me of this:

 

https://www.youtube.com/watch?v=1OfxlSG6q5Y

 

Old toasters are really much better than new ones, and the engineering behind it was impressive.

Message 3 of 10
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I love the toaster design, and Technology Connections.  Whenever the wife hears me watching his channel she will say "What's he saying we're doing wrong now?"  (She does actually like using powdered dish detergent but won't admit it)

Message 4 of 10
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wiebe@CARYA wrote:
I'm sure you are aware, but when opening a microwave the high voltage isn't the only danger. I guess 'don't try this at home' applies.

When just removing the cover, the high voltage seems to be the only serious problem (see also), i.e. about 2 electrocution deaths per year on average due to microwave repair attempts. There are even warning stickers all over the place. Other dangers would happen if you "dig deeper", e.g. would start taking apart or destroying the magnetron, which could expose you to e.g. toxic beryllium oxide. So don't use it as target practice. I did have a second person in the room, just to be sure. 😄

 

Even as preschooler, I had some encounters with 220V in Switzerland, e.g. making my own "extension cords" 😮 . The US 110V is mild in comparison. Yes, the voltage in a microwave capacitor is quite high. 5kV!

 

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Message 5 of 10
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@altenbach wrote:

When just removing the cover, the high voltage seems to be the only serious problem (see also), i.e. about 2 electrocution deaths per year on average due to microwave repair attempts.


That's pretty low considering other microwave experiments have killed at least 33 people since 2016.