I have an Amana top mount refrigerator with the freezer on the bottom .
It won't do an automatic defrost. I have checked the heater coil and
defrost thermostat and both seem to be working just fine. I have
tracked the problem to one of two boards (I think) Either the low
voltage or the high voltage pc board. I don't want to just replace them
both as they are a little over $100 each. Also I haven't had any luck
with the online repair diagnostics (for a fee) Anyone have experience
with this? Model #B136CAL1.

Thanks

Bob

90% of those is a bad defrost heater coil.
It will measure good when cold. As soon as it heats up it will open
up.
To verify, pull the heater coil and hook up to a variac to heat it up.
Monitor the current pull on the coil and the heat output (be careful).