Emil S 21:27 05 Apr 2018

Hi Everyone,

I bought this broken PSU from my friend there was 3 capacitors missing I have 2 capacitor but one is still missing because I don't know what type it is, my friend told me that it was ceramic capacitor green/grey but he lost it :-( Please see attached picture maybe someone can help me ???

Sorry for my English but it's my second language :-)

click here


  Emil S 21:31 05 Apr 2018

Please se below link to pictures

click here


  alanrwood 10:26 06 Apr 2018

Are you sure it is a capacitor. The motherboard symbol in the position you have ringed shows it as a resistor not a capacitor.

  Emil S 11:09 06 Apr 2018

Thank you for replay. Im not sure because I never did ths before and my friend he is not sure too. Do you know what type of resistor it could be?

  Emil S 11:13 06 Apr 2018

My friend told me that the part was a circle and green / gray size about 1-2 cm

  Emil S 11:59 06 Apr 2018

I found it its thermistor but Im not sure if it is ptc or ntc thermistor?

  [DELETED] 14:49 06 Apr 2018

Looking at this circuit diagram it's an NTC resistor, marked NTCR1 on the disgram. The capacitor is another 470µf 450 volt.

  Emil S 15:57 06 Apr 2018

Thanks yes it is NTC but what spec should I buy NTC 10D-11 10 ohm B 3A ?

  alanrwood 16:17 06 Apr 2018

I wonder why you are taking the trouble to fix a PSU which rated at only 200W. It is most likely not powerful enough to run anything reasonable.

Where on the circuit diagram is it located. My old eyes find it difficult to focus.

  Emil S 19:28 06 Apr 2018

This is EVGA 850 GQ, 80+ GOLD computer PSU 850W. There is 3 part missing 1x PNP Transistor, 1x capacitor 270UF, 450V and one NTC Thermistor but I dont know what specs should the thermistor have. Im thinking to buy 10D-11 10 ohm B 3A but not sure

  [DELETED] 19:35 06 Apr 2018


I wouldn't take too much notice of the circuit diagram I posted, it was only really an example because the input circuitry is much the same for all SMPSU's in computers, the one the OP is repairing is a big 850W jobby, so it might be worth repairing, as for the Thermistor, to give it its proper name, is located on the mains input side, top left hand corner. They are there to reduce the surge current popping the bridge rectifier at switch on, they are only a few Ohms and as the current through them heats them up the resistance reduces.

I'm not sure what size the OP requires, but there is a lot of information on the internet with the associated calculations, this is one, to find out what resistance and size is needed, but my guess without working it out it will probably be no more than 10 Ohms or so.

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