BFL13 wrote:
Thanks, I will just have to get my head around this.
The in-rush thermistor (black disk on legs, bottom right in the photo) is supposed to protect the bridge rectifier. (I had some thermistor issues with a converter)
The problem with mine was "hot restarts" where the thermistor did not have a chance to cool down before 120v was again applied, so it could not do its job of protecting the rectifier.
No idea if the OP could have done anything like that. With mine you could tell, where the thermistor was cracked across the disc and chunks of it fell off. It still worked even so, until more damage was done and it caught fire. Actual glowing red spot on the black disc that had flames coming out and some smoke.
Didn't blow the glass fuse though. Replaced that thermistor with a different size and no more trouble. Converter worked with just a new thermistor. ( It needed a lower R, not more whatever ? joules? anyway going to a 2R instead of a 5R cured the problem with mine. That 9280 has a 1R.
The thermistor limits the in-rush current that passes through the system to charge up the capacitance on the DC side and are common on power supplies. The ceramic fuse protects against high current either in a failed bridge rectifier or in any of the DC components. If you short the red and black wires, you’re effectively shorting the AC input wires via the diode bridge. That’s why I suggest isolating the bridge itself from the other components.
My fun with a failed in-rush device was in the $1000, 2 year old air handler blower motor in my home HVAC system. $7 to fix.
