GE SxS defrost question

[diverboy1980]

GE SxS with motherboard. Heater was dead and was causing it to ice up. Replaced heater and it has been outside running for about 2 weeks now. Temperatures outside have been high 70 low 35 lately. I checked the frost pattern on the evap today and it looks great. The temp recorded has been in the freezer for the entire 2 weeks and has been fluctuating between 0 and 5 but has not shown it to have went into a defrost. Does the GE with the motherboard go into a defrost on a set schedule or will it only defrost when needed kind of like the adaptive defrost systems?

[JWWebster]

Here is how it all goes down: Adaptive defrost control notes with service manual

[diverboy1980]

Looks like I will be waiting for 60 hours of compressor run time before I know if it's working properly.

[Blazeracer]

I own a shop and we do about 20 a week. Here's the deal if a GE doesn't defrost. First visually inspect the defrost sensor, it should not be bulged. If it is test it then relplace it. If it's good, test the element. If it's bad replace it, if it's good the we replace the thermistor and the heater comes on every time. That the little white thing on a silver clip attached to the copper return tube on the evaporator.

[tgoods]

I test for defrost problems at the control board.  First I attach a jumper wire between power and defrost.  If I get an amperage reading, I know the heater and limit are good.  Then I check the resistance of the evaporator thermistor.  The thermistors will get moisture in them and the resistance will be way lower than normal. I haven't seen a control board cause a no defrost problem but it's definitely possible.  All of the defrost problems have been heaters or evaporator thermistors.  I've replaced a few limit thermostats that were bulging but still tested good and were not the underlying cause.