GUIDE - How to make your own PCIe extender with molex.

[CrazyGuy]

If you're like me, you're not willing to shell out 27 bucks for a molex equipped extender from Cablesaurus or eBay. Fortunately they are pretty easy to make. Thanks to haploid for some tips.

What you'll need:

• Cheap extender cable
• Molex cable with female connector
• Wire strippers
• Soldering iron
• Exacto knife
• Electrical tape
• A few minutes

What you'll do:

• Seperate all 5 12v lines from the extender cable with exacto knife. Side B - Pin 1,2,3.  Side A - Pin 2,3(PCI Express Pinout)  Edit: Note: Side B is not facing the camera in the photo below! Side B is face down.
• Sever the 12v lines and strip the sides going to the PCIe female connector. Be very carful not to sever pin 1 on side A, this is the present pin which tells your motherboard that a device is connected.
• Sever and strip the 12v line going into your molex female connector. Pin 1 (Molex Pinout)
• Solder the 5 12v lines from your extender to the 12v line on your molex connector and wrap with electrical tape.
• Buy $20 worth of bitcoins with the money you saved!

NOTE:
PCIE 1.0 spec specified pin B3 as reserved. Pin B3 was changed to 12v with 1.1 spec in March of 2005. If you are mining with a 1.0 spec card, x850 or lower, do not route B3 to molex (Use A2,A3,B1,B2 only). The instructions above are valid for all pci 1.1 - 3.0 spec cards(x1800 and above).


Finished Product:

[kliffen]

Thanks for the guide! Was looking into making one myself the other day, but i got abit stuck in the process. Thanks!

[bulanula]

There was some discussion about pin B3 being listed as "reserved" in the older specification for PCI-E.

Are we sure that this should be 12 V and it works without problem ?

Otherwise, excellent guide !

[Cablez]

I have managed to make the cablesaurus rev2 type with the molex wired directly to the pcb.  It is a bit more sturdy but much more difficult to build.  If you have good hands and a small soldering iron give it a try.

This way is much easier by comparison and works just as well.  Great guide by the way!   

[CrazyGuy]

There was some discussion about pin B3 being listed as "reserved" in the older specification for PCI-E.

Are we sure that this should be 12 V and it works without problem ?

Otherwise, excellent guide !

Interesting... I found some other specs online showing the B3 connector as reserved too. Looking a bit deeper though, it appears the spec changed with pcie version 1.1 in March of 2005. (http://www.fpgarelated.com/usenet/fpga/show/65714-1.php) Original specs are a bit hard to come by but here is another reference supporting B3 as 12v.(interfacebus.com) I am currently using the connector pictured without issue and cablesaurus is using the same 5 connectors.

Still, if someone is mining with a 1.0 spec card, x850 or lower, sending power on B3 may not be a good idea. I'll update the guide to reflect that. Thanks!

[bulanula]

There was some discussion about pin B3 being listed as "reserved" in the older specification for PCI-E.

Are we sure that this should be 12 V and it works without problem ?

Otherwise, excellent guide !

Interesting... I found some other specs online showing the B3 connector as reserved too. Looking a bit deeper though, it appears the spec changed with pcie version 1.1 in March of 2005. (http://www.fpgarelated.com/usenet/fpga/show/65714-1.php) Original specs are a bit hard to come by but here is another reference supporting B3 as 12v.(interfacebus.com) I am currently using the connector pictured without issue and cablesaurus is using the same 5 connectors.

Still, if someone is mining with a 1.0 spec card, x850 or lower, sending power on B3 may not be a good idea. I'll update the guide to reflect that. Thanks!

Glad to be of use.

However, I doubt anyone is mining with ATI x850 or lower

But still good information because I have an old ATI x700 Pro card and if I used that card on an extender it would have fried and people could be blaming you etc.

[ModusPwnd]

Thx for this guide.  I could have used this a week ago before I hacked up two of my connectors!     Fortunately I got one of them to work.

I was not sure at first if I could just sever the connection the to the mother board or if I should tap into and preserve the connection.  I ended up not connecting the power to the motherboard, as I see you did not. 

I also tried desoldering the joint at the connector too.  That was pretty easy.

One issue I had was stripping the thin wires.  My autostrippers didnt work on that thin gauge.  I used a razor, but would like to look for a proper stripper.  Would the cheaper plastic autostrippers work on a ribbon?  Any idea what gauge the ribbon is exactly?

(Also, I did mine on PCIe x1 - PCIe x16 adapters, seemed to work just fine. )

[haploid23]

Ah looks like powered extension cables are starting to be mainstream now, that's good to hear. Here was one of the last batches I made for people. It takes roughly 20-30 minutes each:

https://bitcointalk.org/index.php?topic=38725.0

[FLHippy]

If you're like me, you're not willing to shell out 27 bucks for a molex equipped extender from Cablesaurus or eBay. Fortunately they are pretty easy to make. Thanks to haploid for some tips.

Hi,

   Can anyone tell me what the 12v power is for? I wanted to buy a cable to get one of my MSI r7970 cards moved over a bit more and found this cable...

http://www.amazon.com/BestDealUSA-Express-Extender-Extension-Ribbon/dp/B00646VJDG/ref=pd_sim_pc_1

   But in the same search results was this post. What is the 12v power for?

[scifimike12]

Hi,

   Can anyone tell me what the 12v power is for? I wanted to buy a cable to get one of my MSI r7970 cards moved over a bit more and found this cable...

http://www.amazon.com/BestDealUSA-Express-Extender-Extension-Ribbon/dp/B00646VJDG/ref=pd_sim_pc_1

   But in the same search results was this post. What is the 12v power for?

For powering graphics cards, CPUs, fans, etc.  The reason why some may need a Molex or external power connector with their extender is because the 24-pin ATX connector can only supply so much current before something like this happens.  If you're populating a bunch of PCI-Express slots and/or using power hungry cards (ex: 5970), then it would be advise to do this mod.

I would definitely recommend you getting that particular cable from BestDealUSA.  I bought a few from that seller and had nothing but good experiences.  Top notch cables, great prices, and shipped very quickly.

[matauc12]

Just to make sure, you ONLY connect the wires leading to the female and leave those leading to male hanging (mobo side)? I'll just use thumb caps so I don't have to undust my soldering iron

[CrazyGuy]

Correct, you don't want to push voltage to the mb v out, prob wouldn't end well.

[matauc12]

Correct, you don't want to push voltage to the mb v out, prob wouldn't end well.

Yeah, totally what I was thinking but told myself it was better to ask anyways considering I'm not playing with pennies.

Thanks for the guide.

[CrazyGuy]

Are you sure that is the B side (in the photo)?

Yes I believe so, although it's not really clear from the pinout diagrams available. I figured it out which side was which by looking at the extenders haploid and cablesaurus were selling.

[philips]

Some pictures for help:

The A side is the back side of the card (solder side) with the two 12V pins and the presence (PRSNT1#) pin.





The B side is the front side of the card (with the bulk of the components) with the three 12V pins in a row.




Thanks for the guide BTW.

[CrazyGuy]

Well that's interesting, I believe you are right. I did have this extender running in my rig for a few months without issue, so either my motherboard did not need a response on the present pin or 1 of the other pins serves the same purpose... I'll correct, thanks.

[philips]

[Wilderness]

Just made my first ones and managed to get them to work. I had a few problems, thanks for the guide

• the photo with B written on side A confused me, but the picture bellow posted by someone else cleared that up
• the molex connector I harvested had the red wire in one of the middle slots, at first I mistakenly assumed it just went there but the fans didnt start. Next I again mistakenly assumed that it had to line up with the red wire on the PSU but it turns out the yellow cable (at least for my PSU) was the 12v connector that finally got it to work

[petala]

Some pictures for help:

The A side is the back side of the card (solder side) with the two 12V pins and the presence (PRSNT1#) pin.

http://www.xbitlabs.com/images/video/geforce6600gt-oc/power_back.jpg



The B side is the front side of the card (with the bulk of the components) with the three 12V pins in a row.

http://www.xbitlabs.com/images/video/geforce6600gt-oc/power_front.jpg


Thanks for the guide BTW.

I can confirm this works nicely.

Is the 3.3 volt power draw much to warrant cutting these and wiring them to the PSU separately avoiding the mobo?

[philips]

Nah, dont bother with those 3.3V pins.