- Joined
- Nov 18, 2001
- Location
- Troutman, NC
Ok, I finally got off my lazy butt and wrote this up, I hope it helps some future/current farmers out there. I have to give most of the credit to some guy named "Steve" at the no longer existing Free-DC forums where he had a rather extensive write up on this subject.
[STANDARD DISCLAIMER]Use these instructions AT YOUR OWN RISK. This worked for me, but there are no guaruntee's that this will not destroy your PSU and/or mobo! You could also endanger yourself if somethings shorts out.[/STANDARD DISCLAIMER]
The main advantage of running 2 mobo's off 1 PSU is space and heat. In my setup, here, you will see that I would have been hard pressed to fit 1 PSU per layer in that envelope.
Some may argue $$, but the PSU's I used were only $15 +shipping. I do not know if running 2 mobo's off 1 PSU uses less power than 2 mobo's/2 PSU's, but it sure feels like it should.
So here we go, How to Run 2 motherboards off one PSU the cheap/easy way, no soldering!
You will need:
(1) PSU (that you don't care too much if you kill it, in other words, DO NOT try this with your brand new PCP&C!)
(1) extra ATX power connector
(~20) gray wire nuts (16 gage?)
wire strippers
diagonal cutters
(~2) cold bud lights
1. First, you must pick a PSU for this operation. I have used cheap-O 300W Cogeden PSU's and they seem to have no trouble powering 2 M7VKQ's with Duron 1.2's.
2. This next thing to track down is an extra ATX connector with wires. Old/Dead PSU's are great for this, just cut all the wires as long as possible. I have even used old AT PSU connectors and wires, the only problem being the different color wires, it can get a little confusing.
3. Strip the ends of the wires of the extra connector and twist them up nice and neat. I like to strip about .25" when using wire nuts, just to make sure there is no bare wire showing.
4. Here's the tedious part. Now starting at Pin #1, cut the wire about 2" or 3" from the PSU. Strip each end, and twist them up with the matching wire from the extra connector using a wire nut. (Use any means necessary to make this connection, I happen to like wire nuts for their simplicity) DO NOT CUT MORE THAN 1 PSU WIRE AT A TIME!!! If you cut 2 wires of the same color, you can easily lose track of which one is which, trust me, do one at a time.
5. We will be connecting 18 of the 20 wires. The Green (PS ON) and Gray (PWR OK) will not be spliced. These wires will only be connected from the Main Mobo to the PSU. More on this later.
6. Once you're done splicing, tidy things up a bit and hopefully it'll look better than this.
I usually test the PSU with 1 mobo hooked to the "Main" connector first, just to make sure everything's peachy. Once that's proven, connect the second mobo. You will need, at a bare minimum, switches hooked up to the POWER ON jumpers for each mobo. You can connect the RESET jumpers as well, but since I don't use the RESET switches, I won't get into that.
Here is the power up sequence.
1. Turn on PSU
2. Power up "Main" mobo using the power switch. The fans for both mobo's should kick on, but only the Main mobo will boot.
3. Once the Main mobo has booted, hit the power switch on the secondary mobo, it should start to boot. You may need to hit power on the secondary mobo a second time if the first hit does nothing.
4. Once both mobo's are booted up successfully, I like do it again and check the voltages in the BIOS, I suggest you do the same.
With both mobo's running, hitting the power on the secondary mobo will turn it off, but keep the fan running. Turning on/off The secondary mobo should have no effect on the main mobo. Hitting the power button on the main mobo will power down both mobo's and shut down the PSU.
So far this setup is working great for me. I haven't put a whole lot of thought in to what is actually happening when each mobo powers up, i.e. what signals are being sent to where. I also wonder about how the whole voltage sensing situation works when the mobo's are sharing each rail. Feel free to comment and help me understand why this works, or why it shouldn't!
Good luck and Fold ON!!!!
Here are some more links of Yatta Jr.
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=122568&highlight=yattamonster
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=109433&highlight=yattamonster
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=107333&highlight=yattamonster
[STANDARD DISCLAIMER]Use these instructions AT YOUR OWN RISK. This worked for me, but there are no guaruntee's that this will not destroy your PSU and/or mobo! You could also endanger yourself if somethings shorts out.[/STANDARD DISCLAIMER]
The main advantage of running 2 mobo's off 1 PSU is space and heat. In my setup, here, you will see that I would have been hard pressed to fit 1 PSU per layer in that envelope.
Some may argue $$, but the PSU's I used were only $15 +shipping. I do not know if running 2 mobo's off 1 PSU uses less power than 2 mobo's/2 PSU's, but it sure feels like it should.
So here we go, How to Run 2 motherboards off one PSU the cheap/easy way, no soldering!
You will need:
(1) PSU (that you don't care too much if you kill it, in other words, DO NOT try this with your brand new PCP&C!)
(1) extra ATX power connector
(~20) gray wire nuts (16 gage?)
wire strippers
diagonal cutters
(~2) cold bud lights
1. First, you must pick a PSU for this operation. I have used cheap-O 300W Cogeden PSU's and they seem to have no trouble powering 2 M7VKQ's with Duron 1.2's.
2. This next thing to track down is an extra ATX connector with wires. Old/Dead PSU's are great for this, just cut all the wires as long as possible. I have even used old AT PSU connectors and wires, the only problem being the different color wires, it can get a little confusing.
3. Strip the ends of the wires of the extra connector and twist them up nice and neat. I like to strip about .25" when using wire nuts, just to make sure there is no bare wire showing.
4. Here's the tedious part. Now starting at Pin #1, cut the wire about 2" or 3" from the PSU. Strip each end, and twist them up with the matching wire from the extra connector using a wire nut. (Use any means necessary to make this connection, I happen to like wire nuts for their simplicity) DO NOT CUT MORE THAN 1 PSU WIRE AT A TIME!!! If you cut 2 wires of the same color, you can easily lose track of which one is which, trust me, do one at a time.
5. We will be connecting 18 of the 20 wires. The Green (PS ON) and Gray (PWR OK) will not be spliced. These wires will only be connected from the Main Mobo to the PSU. More on this later.
6. Once you're done splicing, tidy things up a bit and hopefully it'll look better than this.
I usually test the PSU with 1 mobo hooked to the "Main" connector first, just to make sure everything's peachy. Once that's proven, connect the second mobo. You will need, at a bare minimum, switches hooked up to the POWER ON jumpers for each mobo. You can connect the RESET jumpers as well, but since I don't use the RESET switches, I won't get into that.
Here is the power up sequence.
1. Turn on PSU
2. Power up "Main" mobo using the power switch. The fans for both mobo's should kick on, but only the Main mobo will boot.
3. Once the Main mobo has booted, hit the power switch on the secondary mobo, it should start to boot. You may need to hit power on the secondary mobo a second time if the first hit does nothing.
4. Once both mobo's are booted up successfully, I like do it again and check the voltages in the BIOS, I suggest you do the same.
With both mobo's running, hitting the power on the secondary mobo will turn it off, but keep the fan running. Turning on/off The secondary mobo should have no effect on the main mobo. Hitting the power button on the main mobo will power down both mobo's and shut down the PSU.
So far this setup is working great for me. I haven't put a whole lot of thought in to what is actually happening when each mobo powers up, i.e. what signals are being sent to where. I also wonder about how the whole voltage sensing situation works when the mobo's are sharing each rail. Feel free to comment and help me understand why this works, or why it shouldn't!
Good luck and Fold ON!!!!
Here are some more links of Yatta Jr.
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=122568&highlight=yattamonster
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=109433&highlight=yattamonster
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=107333&highlight=yattamonster