I have a wine cooler with two Peltier units and a power supply for each. One PS is working, the other one does not. Two leds on the working one light up but not on the dead one. I've replaced all caps and a large IC. There is a smaller IC that I learned is an op-amp. (I don't mind admitting that I'm shooting the parts cannon at it.) The values are drastically different from the other board but I don't know if the op-amp is bad or if the strange values are because of some other component(s). Any suggestions on how to determine whether I should order the op-amp? Thanks for any help. PS: component is LM358P.

 

LM358 is cheap. Where's the harm?
If it is a switch mode supply then they can be impossible to repair without a schematic and knowledge.

 

LM358 is cheap. Where's the harm?
If it is a switch mode supply then they can be impossible to repair without a schematic and knowledge.

Yep, I don't have any problem with the cost (nickels and dimes). But part of this project is to learn. I've tested every component that I could find a test for, and it's helped me a lot as far as learning. I thought there might possibly be some way to check one of these with a meter so that I could go ahead and feel good about having found the problem. I'll just go ahead and order one.

 

You can't do a simple test on an op-amp. You would need to put it in a circuit where you know what voltages to expect and see whether fact matches expectations.

 

You can't do a simple test on an op-amp. You would need to put it in a circuit where you know what voltages to expect and see whether fact matches expectations.

I went ahead and swapped the opamps of the two boards and found them both to be good. The good board works with either opamp while the dead board works with neither of them. Back to the hunt. Thanks for the responses.

 

If you can post some photos of the power supply it might be helpful. That will give us a better idea of the general nature of it.