Converter In-Rush Thermistors etc, UPDATE -4
UPDATE on 17 Nov, Update 2 on 22 Nov, Update 3 on 16 Jan 14, Update 4 on 19 Oct 14. --------------- In a recent thread there was mention of how you can wreck your gizmo (in my case a converter) ...
Forum Discussion
I would buy a couple of spare thermistors, replace the failed one, and be more careful with the power cycling. Wait at least a minute before you power the converter back on after it's been turned off, and don't turn it on into a full load. Thermistor failures from repeated, short duration power cycling are common. There are other more robust methods to use for inrush limiting that involve FETs or relays, but they cost more to implement...so many manufacturers rely on the simple thermistor, despite its drawbacks.
If you find that the thermistor continues to fail with more careful power cycling, then there may be a design issue or other component failure.
You can always do some simple checks first, too. If you have DMM, you can easily test the rectifiers on the input for shorts. Do this with the unit off and wait until the filter caps have fully discharged. Also, after the converter has been running for a while, turn it off/disconnect it and feel the filter caps. Are they hot to the touch? They may be warm, but should not be excessively hot. If they are too hot, they may be underrated for the application or they might be drying out.
EDIT: I might also add that a sustained overvoltage from your generator could also be causing this, but is probably unlikely.
If you find that the thermistor continues to fail with more careful power cycling, then there may be a design issue or other component failure.
You can always do some simple checks first, too. If you have DMM, you can easily test the rectifiers on the input for shorts. Do this with the unit off and wait until the filter caps have fully discharged. Also, after the converter has been running for a while, turn it off/disconnect it and feel the filter caps. Are they hot to the touch? They may be warm, but should not be excessively hot. If they are too hot, they may be underrated for the application or they might be drying out.
EDIT: I might also add that a sustained overvoltage from your generator could also be causing this, but is probably unlikely.
