This hotplate stirrer stirs but the hot plate doesn't heat up. The potentiometers are fine as I replaced them new and I can hear the relay clicking when I turn the knob for the heating plate. Also this voltage regulator circled gets really hot. I replaced it new but this part still gets hot. Any help diagnosing this voltage regulator and heating function on this hot plate stirrer?

 

That part you have circled looks like a regular BJT transistor.

Do you have a schematic?

Have you taken measurements at different points in the circuit to try to narrow the problem down?

 

At a guess, and if it really is the voltage regulator (it could be a 78L05 in a TO92 package) then one of the logic ICs has failed.
Try removing any that are in sockets and see if the regulator cools down. The large one (which I suspect is the most likely to have failed) is probably a microcontroller, and you will have to get that from the product manufacturer.

 

That part you have circled looks like a regular BJT transistor.

Do you have a schematic?

Have you taken measurements at different points in the circuit to try to narrow the problem down?

Unfortunately Corning does not provide any schematics or replacement parts. Ive looked all over. I haven't taken any measurements, only measured individual parts. I'm still a novice and still learning how to methodically diagnose pcbs .

 

At a guess, and if it really is the voltage regulator (it could be a 78L05 in a TO92 package) then one of the logic ICs has failed.
Try removing any that are in sockets and see if the regulator cools down. The large one (which I suspect is the most likely to have failed) is probably a microcontroller, and you will have to get that from the product manufacturer.

Well I removed the microcontroller from the socket but this regulator is still overheating.

 

At a guess, and if it really is the voltage regulator (it could be a 78L05 in a TO92 package) then one of the logic ICs has failed.
Try removing any that are in sockets and see if the regulator cools down. The large one (which I suspect is the most likely to have failed) is probably a microcontroller, and you will have to get that from the product manufacturer.

When i plug in the power cord the motor starts auto spinning even without turning the potentiometer and the regulator over heats. I took your advice and I switched this microcontroller with another working units microcontroller. With the working pcb microcontroller when i plug in the power cord the motor doesn't auto spin anymore but this regulator is still overheating.

 

Ive confirmed its the microcontroller that's faulty by switching the faulty one with a working one from a working unit. Is this microcontroller replaceable or is this unit for parts only now?

 

I replaced the faulty microcontroller with one from a working unit, but the hot plate stirrer is now showing the same issue: the motor turns off, the hot plate stops heating, and the regulator becomes hot. The microcontroller works like normal when i switch it back to the working unit. Any recommendations on what else I should check or diagnose on this unit?