Latest on ol' PZS25KSEBFSS. Seems that it’s not fixed after all. I thought for sure that the replacement of the ground wire to the motherboard would fix it (wrong). It seemed subjectively to last a bit longer but froze up again.
I went out to the shop and got my tools and kneepads and extension cord and hair dryer and turned off the fuse in the basement and put the food in a cooler and pulled out the drawers and took apart the blower assy. and defrosted it again. I hoped it would work (nope). Froze up again.
This time I let it go like two weeks until the milk was spoiled and the evaporator was just a solid block of ice. Defrosted it again, hoping against hope, and 10 days later, the evap. froze up again, inevitably.
Based on the reading of the measurement points on the motherboard from the previous post, I decided to replace the thermistor in the freezer, just in case incorrect readings in the freezer was making the fresh food section evaporator fan to not shut off. I ordered the thermistor, waited for it to arrive, I defrosted the evaporator again and also took all the food out of the freezer and disassembled the freezer blower/evaporator assembly. I carefully soldered in the new thermistor for the freezer and put everything back together one more time. My son, walking past me down on my knees and all the disassembled parts around me said "Dad, are you ever going to get that thing fixed?" I was sure it was gonna work this time. Ten days later, froze up again.
I thought hard about installing a piece of 2" car heater conduit to the side of the evaporator so I could defrost it by going down to the basement, turning off the fuse, pulling out the drawers and running the hair dryer through the conduit to defrost it, and repeating this every 7-10 days, forever.
I finally gave up and ordered a new motherboard ($250) thinkin' that one of the little relays that turns off the compressor (or whatever it's called) during the defrost cycle was stuck and leaving the compressor to run constantly. It's a theory. Besides, this model is infamous for mother boards failing. I did everything again: tools, fuse, drawers, disassembly, defrost, reassemble, put away tools. Froze up again.
This time when I took it apart I noticed that the plastic evaporator/blower cover was frozen right up flat against the vents where the fan is supposed to get the air from, to blow air across the evaporator and up the channel to the very top of the fresh food compartment. I noticed that the second drawer, the produce drawer, when pushed all the way in blocked those vents! I tried leaving it out a little bit to leave a space in the back for the blower to breathe. It was driving me crazy because I couldn't trust the family to remember to leave that drawer pulled out a little bit! I went out to the workshop and found some 1" thick pieces of that dense white foam that they use to pack electronics for shipping. I cut two approx. 2" squares and used double sided foam tape to stick them to the top of the second drawer, the one that was blocking the air. So far it works! I can peer back there with a flashlight and the coils seem to be clear with only a light covering of frost, and the fridge is cold as heck 36º F!
I'll keep you posted Jake, on what happens next....