This is literally evidence of stuff being designed to fail. An extra diode costs less than a cent at production scale. This was a manufacturing choice, not an error.
I don't think it's so much an issue of designed to fail as trying to get it as cheap as possible.
Theres further issues with everything coming out of china and a brand slapped on it. No one is left to take responsibility on the engineering front. This feedback I doubt will get to the correct people at best buy, let alone going back to the microwave manufacturer. And then there's the question of if they care, as they aren't a customer facing brand.
My guess is the LED's suffer reverse bias thermal runaway when they're hot from being in a steamy enclosure and then they get a reverse 5v across them and any leakage current turns into heat accelerating the process.
I’m surprised that they chose to add a bunch of components to feed the AC line frequency to the microcontroller instead of just using a 32.768 kHz crystal. A single crystal oscillator seems like both the cheaper and more accurate option
The power line frequency is carefully monitored and adjusted to ensure that deviations from the ideal (60 Hz in OP's case) are smoothed out [0]. Even a single ppm deviation equates to 2.6 seconds per month, and your cheap 32.768 kHz crystal is going to be orders of magnitude worse than that.
I'm so glad that my ancient Moulinex microwave has no display at all and no keypad. Just a motorised dial to set the time and another dial that sets the duty cycle.
My $$$ < 5 year old convection oven recently malfunctioned: with the thermostat off, it still experiences heat cycles (even while clearly showing OFF).
After cooking, I must turn the circuit breaker off (every single time) to avoid overheating an empty stove. Annoyingly, the system still detects that it is hot, because it is hot, while aware that it has technically been "OFF" for hours.
Can't my next new stove just have manual controls and last decades like the one it just replaced?!?
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[ 2.9 ms ] story [ 34.6 ms ] threadTheres further issues with everything coming out of china and a brand slapped on it. No one is left to take responsibility on the engineering front. This feedback I doubt will get to the correct people at best buy, let alone going back to the microwave manufacturer. And then there's the question of if they care, as they aren't a customer facing brand.
But rarely do those failsafes protect reliably against 'the mainboard was splashed with salt water'.
Even with triple redundant relays, how do you know the salt water didn't just wet them all?
https://news.ycombinator.com/item?id=41480038
[0] https://en.wikipedia.org/wiki/Utility_frequency#Stability
A public prosecutor should take this on.
Is it necessary to be so skimpy with a safety feature?
After cooking, I must turn the circuit breaker off (every single time) to avoid overheating an empty stove. Annoyingly, the system still detects that it is hot, because it is hot, while aware that it has technically been "OFF" for hours.
Can't my next new stove just have manual controls and last decades like the one it just replaced?!?