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
lorelec wrote:Salvo wrote:
Some further thoughts. Not sure what the dc voltage at the big input caps is, but it maybe somewhere around 150V. I don't believe the cap voltage goes quickly down to 0V when the converter is turned off. Perhaps around 100V, by design, the converter will stop operation. Now there's very little load on the caps and they will slowly decay. That means when you quickly turn the converter on again, there won't be a huge current surge.
When the OP gets the parts, he should monitor the thermistor temperature. How hot does it get? He should also cycle the converter on/off. I bet it will not fail. No need to baby the thing if you don't have to.
Sal
Good idea. It would also be helpful if he monitors the voltage across the input caps when the converter is turned off, to see how fast it falls compared the the thermistor temp. Carefully, of course, given the voltage here. I'm just curious how fast they designed the voltage to bleed off.
First I have to actually get it running again, I am not a tech, so my circuit board repair work is really ugly. Assuming I get that far ok, then I would be happy to take some measurements with my multimeter.
I might need some help where to poke the probes to get the input cap values mentioned above. Perhaps the photo of the new one showing most of the board will help with that. Why be so careful? what voltages are we looking at anyway--not just the 120v? If it is way more, I don't know how high the meter goes. The above quote must be AC 150v not DC?
