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PCI-E 6-pin to 2-Molex Power Y-Adapter Cable Keeps burning

Last response: in Graphics & Displays
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January 6, 2013 12:31:02 PM

Hi I have an ATI Radeon 6770 Graphics Card and the give power to it i use the PCI-E 6-pin to 2-Molex Power Y-Adapter Cable. I only connect one Molex to it and leave the 2nd one not connected. Around a year ago i smelt something burning when i check it was the yellow cable so i wraped it in electrical wire and plugged in the other molex. Rectally that burnt as well. When i turn on my computer without power to my ATI Radeon 6770 all the fans on my computer are running at full speed so i can't use my computer untill i buy the cable. My Question is why dose the PCI-E 6-pin to 2-Molex Power Y-Adapter keep buring and when i plug it out why do my fans run at full speed.

Picture Of Burnt Adapter Cable:

http://tinypic.com/r/59sx0l/6

http://tinypic.com/r/2zfmyar/6

http://tinypic.com/r/n6xqif/6

http://tinypic.com/r/dea1t/6
January 6, 2013 12:36:35 PM

The reason why your fans keep on running at full speed is because if the fans are on 100% then its a indicator to tell you that there isn't enough power going to the card. Its a normal thing. One of the reasons why the adapter burned out might be because it was a bad wire with poor design quality, or it was overloaded with power.
January 6, 2013 1:39:39 PM

quinny31191 said:
The reason why your fans keep on running at full speed is because if the fans are on 100% then its a indicator to tell you that there isn't enough power going to the card. Its a normal thing. One of the reasons why the adapter burned out might be because it was a bad wire with poor design quality, or it was overloaded with power.



Thanks For the reply OK i understand why its happening with the fans but is there any possible way the find out why the wire keeps on burring, could it be because of my psu
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January 6, 2013 1:54:45 PM

There's a reason why it's TWO molex to PCI-E 6-pin. You need to connect both molexes to give enough power. By only having one attached, you risk overloading the one molex plug.
January 6, 2013 2:03:46 PM

One of the posts is spot on here to do with the power draw of the card, by not using the correct power feed you put extra load on the power line, this will cause the wires to heat up and melt. You should of connected both of the the molex connectors using depending on your PSU to each 12v rail output of the Psu to avoid this. Electricity pushes despite any power draw from a device if it is not obviously the amp draw or feed was the problem as it was not balanced across the load of the two molex connections so it melted the cables ect.
January 6, 2013 2:07:11 PM

Could be the 'y' cable is just por quality but Molex connetors are not designed to handle high curents-they're only intended to power disc drives so when you get a replacement you should connect both molex plugs to the powersupply.
It might be a good idea to get the system checked as well, if something is wrong with the card it may be drawing too much power, overloading the power leads and, possibly damaging the powersupply.
January 6, 2013 2:10:11 PM

A HD6770 shouldn't need so much power that it's burning wires, unless the wires are a lot thinner than they are supposed to be.
What brand and model (not just wattage) is your PSU? A modern PSU of any quality will have at least one PCIe power connector. If yours doesn't, it may be so old that it may have most of its output on +5V instead of on +12V where a modern PC needs it.
Essentially, replacing your PSU with a modern unit like a 380W Earthwatts or a VP-450 should solve this problem permanently. If you anticipate a graphics card upgrade, choose 500W-550W; an Earthwatts, or something Seasonic-built (their own, or XFX) would be good. Skip the Corsair V2 Builder, it was made by CWT, not Seasonic, using some inferior Samxon capacitors of a type known to die early.
January 6, 2013 3:52:32 PM

Onus said:
A HD6770 shouldn't need so much power that it's burning wires, unless the wires are a lot thinner than they are supposed to be.
What brand and model (not just wattage) is your PSU? A modern PSU of any quality will have at least one PCIe power connector. If yours doesn't, it may be so old that it may have most of its output on +5V instead of on +12V where a modern PC needs it.
Essentially, replacing your PSU with a modern unit like a 380W Earthwatts or a VP-450 should solve this problem permanently. If you anticipate a graphics card upgrade, choose 500W-550W; an Earthwatts, or something Seasonic-built (their own, or XFX) would be good. Skip the Corsair V2 Builder, it was made by CWT, not Seasonic, using some inferior Samxon capacitors of a type known to die early.


My Psu dose not have A PCIe Power Connector Thats why i have to use this cable and y psu is ATX-500 and what would be a good psu with 500-600w around 30-50 Pounds
January 6, 2013 5:05:29 PM

You can probably find something from Antec or FSP in that price range. Unless you plan on upgrading, a 380W Earthwatts would be sufficient. AMD may say you need a 500W PSU for that card, but that is because they are trying to account for all the junk out there that really isn't good for what's on the label. If you go to a PSU sizing calculator, such as the one at http://www.extreme.outervision.com/psucalculatorlite.js... you will see that a rig containing a HD6770 may not actually need any more than 300W.
January 6, 2013 5:42:13 PM

coozie7 said:
Get 'em while they're hot! ;) 

http://www.dabs.com/products/ocz-technology-500w-corexs...

Meh. It would do, but it doesn't look all that great. It's rated at only 30C; components derate with heat, so in the more realistic 35C-40C you'll find inside a typical PC, it's probably good for 450W max. The "up to" 80% efficiency is not encouraging; perhaps in the middle of its range when cool, but actual efficiency, especially when the PC is idle (where a PC spends much of its time), or under load at over 30C, is probably no better than 75%.
Edit: That said, I would choose this over some nameless Chinese junk any day; just know what you're getting.

January 6, 2013 6:29:32 PM

Onus said:
You can probably find something from Antec or FSP in that price range. Unless you plan on upgrading, a 380W Earthwatts would be sufficient. AMD may say you need a 500W PSU for that card, but that is because they are trying to account for all the junk out there that really isn't good for what's on the label. If you go to a PSU sizing calculator, such as the one at http://www.extreme.outervision.com/psucalculatorlite.js... you will see that a rig containing a HD6770 may not actually need any more than 300W.


Whats Do You Think About This One http://www.amazon.co.uk/gp/product/B0076WGOJ6/ref=ox_sc... and this one http://www.maplin.co.uk/550w-xfx-pro-series-atx-psu-wit...
January 6, 2013 6:57:12 PM

The second one, the XFX, is an excellent, Seasonic-built unit; definitely worthwhile.
!