That’s what I’m going to do, now that it seems to be ok and I’ve disassembled it, I’ll just watch the vents to see if they seem to be frosting up.
Didn’t see any parts inside that would be particularly hard to replace. But I do get a bit nervous working around cooling coils, the slightest breach and it’s junk!
Another note.. the fan itself sometimes fails, but that is a less likely scenario, and usually is preceded by it making a lot of noise (you know - the 'permanently lubed bearings' running out of permanent lube noise.. ;-)
The defrost timer/control is typically hidden in the dress panel inside that has the temp dial (if equipped) and the door light switch. Of course, if your temp control is digital - all bets are off and the price just went up ;-)
The old clockwork timers were easier because if they failed, you could remove the dress cover and manually spin the 'clock' until you heard a click (the switch making up to turn on the defrost tape) and then you could come back in an hour and spin it again to another click (which turned off the heat tape.) If you put things off like I do, you could keep it working for as long as you felt like doing that (which admittedly eventually causes you to break down, buy the part, and fix it correctly..)
The new ones with the solid state circuit are a bit more difficult to bypass and you'd better have a wiring diagram. ;-) Seriously though, check your drip pan once in a while for some water. Usually won't be much because the fan on the compressor is typically situated to blow air also over the pan to evaporate the condensate, but if you look often enough you should eventually catch some liquid in there. No condensate ever is a fairly good indicator of a defrost issue.
And remember, if it's still under warranty, be careful what you do because they just love telling you that you just voided the warranty by doing whatever it was you did.. (Else, use the Clinton defense - 'I don't recall..' or 'I never worked on this unit, not one time..')
Good luck ;-)