Thermistor blown on power supply, please help.

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
Hi all,
My mining rig stopped working a week ago due to it blowing the power thermistor in the EVGA 1000 G 1000w power supply,
I bought another thermistor and fitted it but it’s blown that too, how do I find out if it was a + or - thermistor and is there a right and wrong way of fitting it?
The pic is of the original thermistor, can anyone tell which it was?
thanks,
Phil.
7A80CE75-0BEB-4D83-A3DA-27B2AAF4CC64.png
 
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Thread Starter

Bigfillly

Joined Jan 4, 2019
73
hi E,
Thanks for replying, the only writing on it is what is in the pic SCK 056 it would be 13mm-14mm across if it wasn’t broke,
I fitted a green thermistor with the same writing on it, Did I fit the wrong thing?
Thanks,
Phil.
 

debe

Joined Sep 21, 2010
1,177
SCK are NTC power surge thermistors. Sugest you have a short circuit some where if the new one has blown.
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
That’s good to know, I’ll order another one and give it a closer look again,
Thanks very much for the help debe
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
34428445-2A8F-49EA-979B-9E8F1232153B.jpeg
Hello again,
On looking close at all the components using a magnifying glass and bright lights, I can’t find anything wrong, can anyone point me in the area that could cause a thermistor to blow, turning it on,
Just to clarify this is the psu I’m looking at,
View attachment 169298 View attachment 169299
You can see the thermistor between the 2 coils at the top, it’s striped across the top of it,
Thanks in advance,
Phil.
 
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Tonyr1084

Joined Sep 24, 2015
4,887
Had a stereo amplifier blow the fuse. It was a shorted bridge rectifier. One of the four diodes went short. If your PS has a shorted rectifier, and I'm guessing, may be the culprit.
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
Thanks for the reply tonyr1084 I’ve took the last hour looking over it all again, looking at the rectifiers but nothing looks amiss, I’ve removed anything that could bridge across the terminals, getting all the dust out and I still haven’t found anything bad, even the circuit board underneath hasn’t got ant marks that lead me to a suspect area,
I think I’ll buy a few more thermistors and see what happens when I replace it, I might have bought a bad one?
 

Tonyr1084

Joined Sep 24, 2015
4,887
Just looking at my blown BR (Bridge Rectifier) you couldn't tell it was shorted. It had to be removed from circuit to be tested. The BR is just one possibility.
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
Well that makes sense, I haven’t got a clue how to test that, I might send it in to someone that knows,
Thanks again,
Phil.
 

MisterBill2

Joined Jan 23, 2018
6,675
In power supply applications there are two opposite types of thermistor devices for far different applications. Surge reducers and circuit protectors. But yes, you have something drawing way too much current.

AND, is that a bitcoin mining operation??
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
Hi,
I’ve done a visual check many time but can’t see anything wrong, I don’t have the means for testing components but I would like to fix it,
And yes it’s for bitcoin mining,
Thanks for the reply,
Phil.
 

bwilliams60

Joined Nov 18, 2012
1,330
Do you have a DVOM, soldering iron, any equipment that you might be able to use?
Are any of the caps dome shaped at all on top or leaking at the board? Common on SMPS.
Can you post any clearer pictures from the top? Maybe 4 sections or quadrants so we can have a better look?
 

Thread Starter

Bigfillly

Joined Jan 4, 2019
73
I have a soldering iron and a multimeter, that’s about it, I’ve checked all the caps, none are domed, I’ve checked the chips, resistors, bridge rectifiers, transistors, diodes and the underside is quite tidy,
I’ll get a few close clear pics for you to investigate,
Thank you,
Phil.
 

MisterBill2

Joined Jan 23, 2018
6,675
Given then that this is a high power computer power supply it would make sense to replace it, because the demands of that kind of computer usage are constant and the damage that could be done by a computer power supply going into an over voltage mode is impressive: Destruction of ram and processors. Expensive.
 
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