How to connect an old motherboard with a 12 pins power connector?

On an old machine, the PSU died, and I attempted to change it. However, the power connector to the motherboard seems to be a weird 12 pin connector, and I can't seem to find any adapter with the typical 20/24 ones.

What can I do with these? I am not even sure those really are what I think they are.

The computer actually isn't mine; I am just trying to help out a friend. He has a proprietary software installed on it to maneuver a professional cutting machine, and it can't be installed on another machine. I thought about putting the hard drive in another computer and trying to boot from it, but I am afraid the difference in hardware would make the Windows 98 unable to work. I fear to make "permanent" damage on the system that would require tedious fixing afterwards.

Here is the motherboard connector slot :

The old PSU's connectors (a bit blurry sorry) :

The old PSU model :

And the "new" PSU's connector with 20 pins :

Angry Cub

Posted 2017-09-11T18:46:54.830

Reputation: 375

Max output power 74W? wow. – user253751 – 2017-09-11T23:52:37.507

@user20574 I think that's single channel... otherwise, I would strongly advice against using this on any modern (say, 2008 or later) motherboard. – Braiam – 2017-09-12T01:06:53.817

Having worked with a number of old systems like this, there is a high degree of probability that there is modern software that will control it. Well worth a little research. – Perkins – 2017-09-12T01:17:56.047

1@Braiam No, it looks like that is about what you get from adding up the V*A of each rail, however some of those are obscured by a reflection. – user253751 – 2017-09-12T01:18:48.110

And 360 W input rating (120V * 3A or 240V * 1.5A). That's not very efficient... – ratchet freak – 2017-09-12T09:44:06.447

3This question is better suited for retrocomputing.stackexchange.com – Agent_L – 2017-09-12T15:32:54.583

1This isn't some unknown weird power supply, it is Compaq presario power supply (a weird but known power supply) the part number is listed right there in the photo 337373-001. See my answer for some places to purchase replacements. – Justin Ohms – 2017-09-12T17:51:11.353

It should be interesting to post the model (and/or the pat number) of the motherboard... So someone can see if it exists a modern PSU compatible or adaptable. Moreover it should be useful to post the number and the types of the connector in use. You may obtain more (different) answers. – Hastur – 2017-09-13T09:20:56.433

@JustinOhms Everything is unknown until a guy like you comes and says "I know what it is". As you haven't provided pinout, it's still "weird and unknown, by Compaq" : ) – Agent_L – 2017-09-13T10:35:45.410

As this seems to be a PSU controlled by the motherboard, how can you be sure it's the PSU that failed and not the motherboard? – Agent_L – 2017-09-13T10:37:04.953

1@Hastur I get your point, but my point was more that it wasn't really unknown, it literally has the part number on it. – Justin Ohms – 2017-09-13T18:33:34.913

@Hastur The MB part numbers are in first photo PCA 387432-001, PCB 010190-001, SPARE 387610-001 Here is a link to one for sale on Amazon http://amzn.to/2x1PEHN

– Justin Ohms – 2017-09-13T18:50:51.230

Regarding your aversion to yanking the hard drive, you could clone the drive on another computer and run the clone as a virtual machine. If you're able to get it running in a virtual environment, you no longer have to worry about replacing failed legacy/proprietary hardware if something else fails. (Posting as a reply since it doesn't actually address the meat of the question.) – Mikkel – 2018-02-19T16:17:27.800

Answers

EDIT: I appreciate all the thumbs ups, but as other users have pointed out this is likely not an AT connector. After doing more research, my best suggestion to the OP is to purchase the original part number item to insure compatibility with this system. There are no second chances, once the wrong power supply is plugged in, the motherboard is toast.

It appears, based on research, that this system is a Compaq Presario 22xx series. The specs of that series, and references to the original power supply part number suggest that this is an ATX style power supply. The extra 6-pin plug is typically an auxiliary connection. However, it is highly likely, as suggested by other commentators that this is a completely proprietary power supply. A lot of manufacturers are guilty of creating non-standard systems around this era. I cannot find any standard power supplies that used 12 pin AT/PC style power connectors and a 6-pin auxiliary connector. What is for sure, is that this power supply (not clearly seen in the OP's photo) is also proprietary in shape and size:

So, I have left the original message below, but I think it is prudent to not take chances given the sensitive nature of this repair. Just spend the money on getting the exact original part number.

----- ORIGINAL ----- The connector on your motherboard is an AT connector. The power supply you are trying to hook up is an ATX connector.

You'll need to buy an AT power supply. When you hook it up make sure you attach the two motherboard power connectors with the black wires next to each other.

http://wiki.robotz.com/index.php/PC_Power_Supply_Voltage_Data_and_Connector_Types

Now, I have to ask - What are you doing with this computer from 20+ years ago?

Appleoddity

Posted 2017-09-11T18:46:54.830

Reputation: 9 360

2Ah I see, it makes sense why I had trouble finding information about it. The computer actually isn't mine, I am just trying to help out a friend. He has a proprietary software installed on it to manoeuvre a professional cutting machine, and it can't be installed on another machine. I thought about putting the harddrive on another computer and trying to boot from it, but I am afraid the difference in hardware would make the Windows 98 unable to work, and I fear to make "permanent" damage on the system that would require tedious fixing afterwards. – Angry Cub – 2017-09-11T19:13:46.530

Also, could I use a "ATX -> AT" adapter without risking to damage the motherboard ? – Angry Cub – 2017-09-11T19:14:22.200

23@AngryCub Your friend obviously relies on this computer to remain operational. It might be time to upgrade whatever components rely on this ancient technology. You might fix this problem. You might not be able to fix the next one. – I say Reinstate Monica – 2017-09-11T19:18:11.157

It looks like they exist, so I would assume it is safe. The biggest difference is that AT power supplies have a power switch that toggles on and off with 120v running through it. Modern ATX power supplies are turned on and off by the motherboard. Any solution will have to address how you hook up the power switch. It is possible that you can image the drive and convert it to a virtual machine to run on a modern computer. But that is outside the scope of this thread. – Appleoddity – 2017-09-11T19:20:00.900

12@Twisty it's an all too common problem, someone builds a peice of industrial equipment around a PC and then the PC dies long before the industrial equipment does. Often your only options are to try and fix the retro PC, pay someone to do a custom control system or replace the machine entirely. – plugwash – 2017-09-11T19:52:35.767

8@plugwash I know. I've been there. It's better to face that reality while things are working than wait until a production machine is down and orders aren't getting filled. – I say Reinstate Monica – 2017-09-11T19:54:49.890

11If the software only works on Windows 98 you still might be able to get it running on a modern computer in a VM. – user253751 – 2017-09-11T23:53:29.293

1Something else to consider. The unspoken implication of this is that your friend can't get control software for the cutting machine that runs on a modern OS, which in turn means the machine itself is now an unsupported orphan. Sooner or later it's going to fail, at which point your friend will be completely stuck. As others have said, it will be expensive: top end equipment of this sort can easily cost more than my annual salary, but against that your friend needs to balance the cost of being completely unable to work. – dgnuff – 2017-09-12T00:07:01.703

@Appleoddity on the 20pin connector there is a pin that if pulled to ground will activate the power to the board, there is also a standby 5V pin that is always on when it is plugged in. You can break those out of the adaptor and build a toggle switch with that. – ratchet freak – 2017-09-12T00:47:52.280

@AngryCub Maybe you could try to install it in VM. qemu supports emulation of I440FX/PIIX3 which is roughly in the correct timeline. – Maciej Piechotka – 2017-09-12T05:51:06.397

4Check out retrocomputing.stackexchange.com. With plenty and cheap replacement parts, running a 286 is both easy and economical in 2017. Adapting an old system to accept a new computer can turn out much costlier than buying few ancient PCs off ebay to cannibalize. OP's PC ran for at least 20 years, give it some credit! – Agent_L – 2017-09-12T15:36:02.657

1Take a look at ATX-like rail setup (+3.3V, +5VSB) and the third P-plug. This is not your regular AT, it's some kind of hybrid. – Agent_L – 2017-09-12T15:59:43.677

1@AngryCub you can use a disc cloning software, like the free (as in beer) Clonezilla, to do a full duplication of the hard drive to a new hard drive, and then play around with that clone instead of the original. Try adding it to new hardware, and then using a Windows 98 install disk, doing a Repair Installation, which may get it to boot again on the new ATX motherboard, etc. Don't try it on the original drive, you don't want to break things - but a cloned drive gives you a lot of flexibility. Also, don't clone his original drive multiple times, it could wear it out - clone the clone if needed. – SnakeDoc – 2017-09-12T17:43:56.197

2this is not an AT power supply it is Compaq presario power supply part number is listed in the photo 337373-001 – Justin Ohms – 2017-09-12T17:51:56.310

I agree. I have edited my answer. Thanks for pointing this out. – Appleoddity – 2017-09-12T18:56:00.200

This is a Compaq Presario desktop power supply. (That is what the Compaq spares number indicates.) Compaq was notorious for inventing their own slightly non-standard wiring configurations for power supplies and motherboards. It is neither an AT or an ATX power supply.

You can find reconditioned units but they are expensive here are a few I found.

Memory 4 Less
Impact Computers

Justin Ohms

Posted 2017-09-11T18:46:54.830

Reputation: 274

3If you could provide pinout for this "weird but known", it would be pretty straightforward to construct an adapter for far less than $200. – Agent_L – 2017-09-12T20:48:15.850

@Agent_L Personally I wouldn't recommend that, better to replace with the correct part. I'm sure if someone wanted to do it they could find pinouts somewhere. – Justin Ohms – 2017-09-13T18:44:47.660

As mentioned in the other answer that is an old AT style power connector.

It is possible to connect an ATX power supply using an adapter but there are a couple of caveats.

Your system may need -5V which modern ATX PSUs don't have (some but not all older ones do)
AT power supplies are not controlled by the motherboard but by a seperate power switch. The adapter is likely to have a pair of wires for connecting to your power switch. Depending on your case design you may be able to hook up the existing power switch or you may need to fit a new one to the case somehow.

plugwash

Posted 2017-09-11T18:46:54.830

Reputation: 4 587

No, it's not. There is no -5V in this PSU, but there are ATX lines (+3.3V, +5VSB). Also, there is a third P-plug. This is not your regular AT, it's some kind of hybrid. – Agent_L – 2017-09-12T16:01:14.577

This is neither ATX nor AT power supply. The 2 main plugs (P8 and P9) are regular AT, but there is also an unaccounted for third one and PSU provides +3.3V and +5VSB rails which is something that AT PSUs don't do. Also, it doesn't have -5V rail, which regular AT should have.

My guess is that's an intermediate-era PSU, which internally is ATX (hence the ATX-like configuration of lines), but uses 2 AT-style connectors + a proprietary 3rd one. Your best bet IMHO is to seek help from some hacker with basic soldering skills. Cables from the dead one could most likely be combined with a working ATX PSU to get an operational replacement.

There is a possibility that the 3rd connector is P10/P11 which supplies 3.3V, but if that's the case, where does +5VSB line go? You can buy an ATX to AT-with-P10 adapter, but if the 3rd one is not P10 but proprietary (with +5VSB), it can end badly.

Try asking at https://retrocomputing.stackexchange.com, maybe someone will recognize the setup. But provide better pictures of the plugs and motherboard, with visible cable color configuration and markings.

Agent_L

Posted 2017-09-11T18:46:54.830

Reputation: 1 493

A quick google search will soon give many results for AT power supplies Adaptors for ATX seem quite mad, particularly given that:

The machine is for a control machine, so Im assuming that there is an (ISA?) card interfacing the hardware. There may be a custom BIOS for the control card making moving it very difficult.

Add in cards may need -5 V even if the motherboard doesn't need it to boot, so if you try converting an ATX PSU be prepared for the machine to not control anything, even if it powers. Like the other answers say, get an AT power supply.

I'd also image the hard drive whilst I was about it so this can be replaced if it goes.

EDIT After seeing the other answer, that this is neither AT or ATX, a google search of the part number on the PSU indicates this came from a Compaq Presario. Those things use ATPWR psu, so you'll need a compaq power supply - completely non standard.

camelccc

Posted 2017-09-11T18:46:54.830

Reputation: 178