Switches and functions of microwave oven unresponsive on cold start

Question

I have an old microwave oven which performs most of its functions, considering its age.

There is a slight problem that the switches go unresponsive and the LCD display fails to operate correctly if I do not use it for a couple of days continuously. The switches become responsive once I plug it in for half an hour or an hour. (And I don't mean operate it. Just plug it to the mains and turn on the supply.)

Why does it require such a plugged-in time to warm-up? Reminds me of the cold blooded animals that need to warm themselves in the sun for some time before they can become fully operational. Why do the electronics and the circuits inside the appliance need such a warm-up before it can operate properly?

Answer 1

Why does the electronics and the circuits inside the appliance need such a warm-up before it can operate properly ?

There could be many reasons but I'd put a small wager on it being a leaky electrolytic capacitor. I've had the same problem myself and I found the information on the web about replacing the well-known suspect device and fixed my quite expensive powered speakers.

They just wouldn't activate for about half an hour - it was the anti-pop circuit that was at fault - once the speakers warmed up, it worked fine. I could even turn them off for about a minute and I was able to reactivate them straight away.

Anyway, I'm off on a tangent now so, the message is, it's likely that the problem is a leaky electrolytic capacitor. Search the web for other instances of this happening and see if some folk managed to fix the problem - that's my advice.

Answer 2

With the passage of time and depending on the frequency of operations being performed and the rupturing current, switches tend to develop a carbon film across their contacts. these switches sometimes operate and sometimes they do not. sometimes they operate when you apply higher pressure. such switches have almost reached their end of life and therefore need replacement. Mostly little leaky electrolytic capacitors are responsible for the late response. LCD displays many times start misbehaving with the passage of time. However, no pinpoint reason can be given for your problem.