My '80's Solid State runs but does not heat?

the LCD is bad, 22 year later a great run that.
use flash light to it , see data there that means backlamp dead
buy new one.
THERE IS NO LCD FUSE EVER. it used low power
from he PCB (display drive logic is there only)
the PCB may have fuse or onboard solid state fuse. that self resets if shorts are removed.
if you see no fuse there, F1 F2, etc there is none.!
use the flash light test. first.. OK??
SO DOES OUR POST MEAN , ONLY lcd dead, BUT BOTTONS NOT DEAD and most beep, so beeps dead? see buttons with programmed times, like pop corn etc, do those work?
LCD dead sure makes time set hard
but gee, hit time 11 and run,
see if 11s seconds, runs the fan and Uwave maggy
cooks for 11 seconds. blind./
lots to test there before giving up.

OK only LCD is dead.

Generlly uWave oven fans have sevealr speeds. They are accomplished with an electronci speed control device in the form of a "Triac." That is a solid-state device that can fail sorted, which means the fan will run continuously on "high." It means the uWave oven needs a new controller, which will be expensive.

Could be element could be Hi limit thermostat could be control. In that order. First step is turn breaker off and remove element to make sure the wires are still connected to back of element. Visually inspect element very good for burns or a white powder residue signally the element burned up. Next step is harder, need to remove the oven and take off back panel, there you will find the hi temp thermostat. Check for continuity, if none replace.

if when it shuts off clock resets to first plugged in state, sounds as if control panel is being reset by something (failure of part, or power surge) if clock is still ok and maintains correct time , I'll bet if you notice the cooliing fan is not running correctly (by sound it makes) in those two seconds, this will over heat magnetron and shut off on thermal hi temp (safety) if so fan will need to be serviced by a professional

The problem is the triac, a solid state switching semiconductor that changes the power level in the magnetron.

If the food is not hot the problem is more than likely caused by the triac, this is responsible for switching the power levels in the magnetron, it is a solid state switching semiconductor device.

If the microwave is heating about 50% it is not running at full power, this most likely caused by the triac switching device, it is a solid state semiconductor and rarely fails but I have seen the odd one go.

This sounds like the magnetron has gone, also there is a solid state device called the triac which controls the power level settings. The other two parts that can be a factor is the high voltage capacitor and diode. The repairs with parts and labor can amount to the price of a new microwave oven.

the problem could be with 2 component. The diode or the magnetron. normally when the diode goes bad, the microwave will make a humming sound. The microwave will tend to sound almost normal when its the magnetron. Or sometimes it will make a sparking noise when put to heat.

Hi,
Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Basic Microwave Oven TroubleshootingTips

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