I have done a stupid

Sampsy

Sampsy

Sampsy

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31 Mar 2010
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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.

61MdokQOXPL._SL1299__zpsuumhrvha.jpg


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?
 
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What PSU was it? That looks like a standard 2x molex to 8-pin PCI-E adapter.

Hopefully it hasn't damaged anything else in the system.
 
When buying my GPU from overclockers, I checked before installing with their support which cables to use. I thought about using the molex adaptor and suggested it (it was when I didn't realise the PSU cables were 6+2 for the GPU) and the response was that I could, but it was strongly advised not to as it would melt and likely catch fire if used for any decent length of time.
 
I'm not sure if that top cable isn't actually an 8 pin EPS (or ATX) cable that is used for motherboards rather than a PCI-E cable.

If it is, then they are wired slightly differently, and would definitely cause a problem (although they should be keyed differently so they are difficult to fit, without forcing)
 
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

13874814_10157209167145162_741781409_n_zpszpi4venl.jpg


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?
 
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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 :)
 
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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 :)
Click to expand...

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.
 
Yeah, you haven't done anything stupid, molex adaptors are fine to use, even if they can be a little flimsy. It's just that you started out with a poor PSU.

A cheap PSU such as that (that's a new brand to me) probably isn't capable of reaching it's rated output. That thing can only support 36A on the 12V rail, which works out at 432W! The 34A on the +5 rail tells me it's a very old PSU design.

That PSU isn't even 80 Plus rated, which would set off alarm bells. This is a good example of a unit sold as a "550W", which isn't capable of it:
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=335

EDIT: Found this for sale at a competitor at ~£22.
 
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As above, i have a molex-8pin adaptor in one of my older machines and has been running for years without any problems.

If you're really suspect then do a cable inspection for any burn/scorch marks on the cable.

As others are saying, it's more than likely your PSU not giving out enough power.
 
This is a lesson I learnt the hard way with a cheap psi taking my mother board with it too when it died. Hope you have better luck than that.
 
Sampsy said:
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.
Click to expand...

Modern hardware tends to draw mostly from the 12V output. That PSU is supposedly rated for 432W on 12V. Which probably means that when it ws brand new it might possibly have been able to supply 430W on 12V if the intake air was below freezing. But probably not for long.

Cheap PSUs are often more expensive over time than relatively expensive PSUs.
 
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