Over-the-range microwave issue (sorry, a bit long-winded)
A few weeks ago friends found their 7 year old over-the-range microwave without power; no clock, no interior light, no controls, or any other functionality. The outlet had powered and the breaker was not tripped.
After taking it down and bench testing it in their garage the results were the same, no power. I then verified all connections. All TCO's (thermal cutoffs), fuses, the noise filter, and other components (e.g. lights, transformer, and fans) seem to test okay. Power was traceable from the external cord all the way to the control board connectors.
So I took possession of the microwave and ordered a replacement control board. After installing the new board, to my happiness, everything was fully functional. All the features on the microwave again worked. I left it plugged in for 4-5 hours and no issues.
I returned and reinstalled it and all was good, for about 15 minutes. Then I thought I noticed a slight flicker periodically in the clock. A few minutes later the microwave appears to lose all power again; once again no clock, no interior light, no controls, or functionality. But now the issue is 'clearable' by simply unplugging the microwave and immediately re-plugging it back in.
I took the microwave down and the issue still was present. I have triple checked all connections. After re-plugging the microwave in, everything seems functional again. After a period of time, sometimes minutes, typically hours the microwave looses power again. I tried a nearby outlet in their kitchen, same results.
The issue is even present if the unit has been unplugged for a while, is plugged in and only the clock is set. When it is working, I can run the microwave, the underside light and exhaust fan at full and neither see nor hear anything odd. So reluctantly I took possession of the unit again figuring the replacement control board was faulty.
But 'here's the kicker' when I got it back to my house I can't recreate the issue. So essentially the issue only seems to occur in their kitchen. The original control board was definitely bad. I'm beginning to doubt the replacement control board is also defective.
So the only thing I can think of is the quality of power to those outlets could be an issue. Maybe a breaker or connection issue could be causing transients, spikes, and or brief low voltage situations that perhaps damaged the original control board and is causing the replacement board to intermittently malfunction.
Any ideas or suggestions?
nunyaWho is John Galt?Premium,MVMReviews:
O Fallon, MO
|reply to pikapp159 |
You've probably already exceeded the replacement cost in time, parts, and fuel. Sadly, almost every kitchen appliance is a "throw-away" unless it's something extravagant.
It could be a power quality issue (an open neutral, for example). Usually that would cause additional problems elsewhere in the home.
A simple VOM test can clear up any suspicion on the power quality.
Perhaps the microwave is tailed off of a kitchen SA circuit instead of having a dedicated circuit (like it should). I can't tell you how many times I get a "microwave trips breaker" call, and some Jack Wagon handy man or goofball "installer" from Lowe's Depot has just hijacked the old shared range hood circuit and used it for the microwave. Big difference between a 150 watt range hood and a 1500 watt microwave. If you are plugging into the same circuit just at a different receptacle, then that could partially explain your issue.
...because I care.