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Identifying mystery component

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M0LDY

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I have an old G-Comm 240Vac 13.8Vdc 25amp regulated power supply which has developed a faulty component (I have not seen one before) The small yellow/black/gold component has started to explode when I switch on the power supply. There are tiny holes starting to appear on the component and obviously it wont last for much longer. Anyone have any idea?

thanks

 

If you mean the round part near the blue capacitor, it's a thermistor, possibly used to limit the rush of current into the circuit as it is switched on. If it's overheating it suggests a fault elsewhere that is causing too much current to flow through it.

Brian.
 
You mean this component ( you did not identify):
snap.jpg
If yes, then it is an INRUSH CURRENT control Thermistor (normally having 2Ω~6Ω resistance). As you said it is having hole in it but you did not say whether the supply is working yet properly?
If yes then the this thermistor only needs replacement. If NO then it means the supply is drawing excessive current. Many causes for.
1. Check for Leaky smoothing capacitor (in blue color visible)
2. Check for any leaky transistor in the output stage.
3. Check for any other component causing this excessive current.
Hope I could help.
 
Yes it is still working, however when switching on, there is a flash (from component) and a bang but the PS will still function (at the moment). Voltage and current output appear to be ok.
Will have to go and have a search in my big components box for a new thermistor and try that first.

Many thanks
 

Great news the supply is working properly. If you do not find in the BIG COMPONENTS BOX, simply get a thrown away computer PSU and remove it from there. Just try to match physically, else it will work.
Great day to you.
 
All working now, yes used an old pc power supply from "The Big Box" to obtain a new thermistor.

regards
 

Thats Great the Supply is without problem now, Enjoy.
 

Hi

Wonder if M0LDY could help me please? I have one of these PSU that was being thrown out from my local club which had some problems and someone had been having a go at it!! However, there is an IC missing from between the large blue 470uf capacitor and the brown 0.47uF one which I can see just the black top of in your photo and it is next to the thermister. This item is missing and I have no idea what it is, from your photo it looks as if it could be a bridge rectifier, as all I have are the 4 holes in the pcb, the thermister is also missing, but I now know where to get one of these from.

Any help would be appreciated, the PSU may be beyond repair, but worth a go.

Thanks
Richard
 

Hi,
Can you please upload the picture of the PCB of you PSU or the model number of the same. May I try to help.
 

Hi

It's the same as mentioned at the start of this thread, a G-Comm 240Vac 13.8Vdc 25amp regulated power supply. Away at present, but will post picture later in the month when back home.
 

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