How To: Make a PCI Express 6 pin Power Connector

shantanu · 14-09-2007, 12:58 AM

Written by Spode (16/Oct/04)

http://www.spodesabode.com/content/article/pciepower

The article is written by spode and team and i just found it usefull, so posting here. i edited the article a bit to make it upto mark for today..(the original article had some flaws)
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and this article is just to save your extra bucks for a SMPS..

If you have read much about PCI Express graphics cards, you may have noticed how they now use a 6-pin socket for supplying external power to the board. When we did our testing, only one of the cards came with an appropriate adaptor. As these were not retail cards, we cannot be sure if this will be the case when retail cards are released. Many new power supplies come with the 6-pin connector as standard, so some companies may opt to not include the cable(4-pin molex to 6 pin), and of course many OEM cards have no cables included at all. Buying an adaptor may be hard to do and you may end up paying an extortionate price for it.
However, if you have a soldering iron and a dead ATX power supply to hand, you can make your own.

As you can see from this picture of our 6800GT, it is a very similar format to a standard ATX 20-pin connector. You will also notice the connector is keyed. Luckily for us, there is part of the ATX connector that has a similar enough key to fit without any problems.

As highlighted above, this top section is perfect. Hacking a PSU apart is not the best solution for everyone, but if you are like us you will probably have a dead PSU lying around somewhere. We found the best way to separate the top three pins is to use a hack saw. If you cut from the pin side and angle away from the top three, you have less chance of cutting into the pins you need. A quick clean up with a file or sharp knife will give us an appropriate plug.

You can make your adaptor as long or short as you like by cutting the PSU wires wherever you like. You may just want to solder these wires straight onto your PSU, or you can do as we did and make an adaptor cable.
We hunted around for a couple of old 80mm case fans and stole the female molex plugs. If you use a small flat bladed screwdriver, you can push down the latches on the pins so that they pop through the other side and can be reused. If you happen to have a set of crimpers and the appropriate ends, your life will be a lot easier as you can just crimp a new set onto each cable. If like us, you don't have a crimp tool a little soldering is required.
Once you have the pins removed from the female molex connectors, remove the wires from the pins by levering open the part which crimps onto the wire insulation, then cut the wire off the rest of the pin. You will need 6 pins.
Shown below is the pinout for the graphics card connector. Each of these pins needs to be routed to an appropriate pin on the molex connectors. It doesn't matter which pin goes to which connector, as long as every pin is connected to the right voltage. The 4 pin molex connectors on your power supply use the same colour code shown below. Yellow is +12 volts, and black is Ground. Compare your female molex connectors with the male ones on your power supply to identify which pin is the 12 volt one. You could mark it with a pen to make sure you don't mix them up.

Strip about 6mm of insulation from the ends of the remaining wires on your cut down ATX plug, and give the strands a twist to hold them together. To attach them to the pins, use a pair of pliers to crimp the wire in, using the prongs you levered open to get the old wire out. Now the bare conductors should be held close to the connector, and you can solder them on with a minimum of fuss. Using a knife, lever the latches on the pins outwards, so that when you put them back in to the molex connectors they will stay put.

Double check your pin-outs before finally plugging the card in, and PCI Express graphics should now be yours..

Also check with this diagram to make sure you connect all things nicely and safely..