I have done a stupid

Sampsy · 2 Aug 2016 at 11:03

So I tried installing a radeon 5830 into an older PC with a non-modular poper supply. The 5830 needs a has a 6 pin and an 8 pin power connector, but the PSU only had a 6pin PCI power connector.

So I tried using a molex for the 8 pin - it looked something like the image below except the 8 pin pci connector only visibly had 6 metal pins in it. I presumed that wasn't ideal but tried it anyway and it worked but did result in some crashes under load. So presuming the 6 metal pins weren't delivering enough power I ordered the connector below, which does have the full 8 metal contacts and tried that. The PC was running Dark Souls 3 for a bit then there was a loud bang and sparks.

Now I've always been pretty ignorant as to how PSUs work and would like to take this opportunity to change that. Why was what I did stupid and what should I have done? Should I try to turn the PC back on, removing the GPU or will that risk further damage to other components?

Sampsy · 2 Aug 2016 at 22:14

Sorry for the delay, I was out for the day. Here's the PSU, and I fixed the images in the OP.

It's looks like a 650w Alpine PSU (JSP-650P12P). I've personally never heard of Alpine

It did occur when the PSU would have been under most load, as the PC was running Dark Souls 3 at the time.

But is the problem simply that the PSU wasn't able to output enough power or was the molex setup actually the problem? I had presumed if molex to 8 pin pci-e adapters existed then it was fine to use them. I'd have also thought 650w would have been more than enough for the setup - it was in general a low end PC with an i3, not many fans or hard drives etc. That said I'm aware bad PSUs often can't actually output their rated wattage. However I don't want to blame the PSU if it was actually my fault, as I won't learn my lesson that way. Also, should I disconnect the GPU and try to power the system back on or will that risk damaging other components further?

Sampsy · 2 Aug 2016 at 23:00

southernorth said:
Is this you

https://www.youtube.com/watch?v=f6snWfd1v7M

I wasn't actually using the PC at the time, but I showed that video to the person who was and they said that it could have been that.

Sampsy · 2 Aug 2016 at 23:06

Minstadave said:
The adaptor wasnt the problem, they're fine to use, that PSU looks like junk and is probably now dead.

I wouldn't try and turn it back on, replace the PSU and hope it had the good decency not to fry anything else with it when it died.

Use this opportunity to get a decent PSU with all the PCIE connectors you need, you can get rid of the adaptors too then

Ok. I feel slightly better that the Molex method wasn't what did it, though I should have seen the PSU failure coming. I had heard cheaply made PSUs can fail like this but have never had it happen before. I never knew they would fail when the power draw was so significantly below the rated wattage. I though perhaps a cheap 650w psu might fail at 600w for example, but not below 400w which the system was likely drawing.

Well I won't try to turn the system back on and I have ordered a replacement. Hopefully nothing else fried.