I am hoping to get some advice on the next steps regarding my defrost issue with my fridge.
It started with the fridge not defrosting and quite a bit of learning after that.
Fridge/freezer runs fine until the coils freeze with ice and the fridge warms up. If I initiate a defrost test the fans/compressor stop as designed by the defrost heater does not appear to warm. After a certain amount of time the fans start back up and the fridge stays warm while the freezer continues to cool.
Steps I have done:
Replaced both freezer thermistors. Show ohms count at 0 degrees at approximately 40,000 which is in the right range.
Tested the temperature overload device and show it has continuity when it is below 45 degrees.
Tested continuity from the main control board through the defrost heater when the freezer is cold and it shows 38 ohms which is correct based off of the schematics.
Replaced main control board that I ordered off Amazon (No change)
As everything shows good except the board I decided to purchase another board. Here is where I am scratching my head. I received the new board yesterday. Installed it and let the freezer/fridge cool down. When I started the defrost test there was a huge pop and sparking in the main control board area. I opened it up and the new board was charred on a resistor directly above the defrost heater power. The resistor has a J16 right next to it. I looked at the original board and while it doesn't have the same amount of damage that resistor also appears to be shot.
So the question is, if all the defrost heater components show good, is there something else that is bad? Was it just a bad board? What other dependencies are there and does that resistor point to a problem elsewhere?
Thanks in advance,