I think the Compaq Deskpro EN is from the era where Compaq were using the ATX connector but there are some differences in the pinout. That turning on then off is probably either a short or a lack of power-good signal.

Thermalwrong wrote on 2024-04-04, 12:17:

I think the Compaq Deskpro EN is from the era where Compaq were using the ATX connector but there are some differences in the pinout. That turning on then off is probably either a short or a lack of power-good signal.

I could rewire the connector, but where to find correct schematic? Or even better, the adapter

Do you still have the old board and the old (original) power supply from the system? If you do, snap a picture and post it here. There's a good chance the old PSU and motherboard used a non-standard pinout on the ATX connector. And if that's not the case, then I'd suspect something is shorted on the new board.

I don't have the board any more, I gave it to a friend, this is why I am putting the other board in the case (also compaq).

I still have one image of the old board.

Can't confirm 100% by the picture of the PSU connector if the pinout is non-standard, since I need to see the color of the wires coming in the back... but from what I can make out from this one, it sure does look like a non-standard pinout. The picture of the label for sure suggests the PSU is from that era when Compaq (and Dell) used non-standard pinouts on the ATX connectors. Shame, because it's a nice PSU to re-use (most OEM PSUs from that era used Japanese caps only, so they are pretty much bullet-proof).

If it does turn out to be a non-standard pinout, you might also want to give the PSU to your friend to power that motherboard you gave him. Less headaches for him too, should he try to use a regular ATX PSU and wonder why it's not working. 😁 (Or worse, if something blows up, due to the ATX connector being completely different from a standard one.)

momaka wrote on 2024-04-04, 22:17:

Can't confirm 100% by the picture of the PSU connector if the pinout is non-standard, since I need to see the color of the wires coming in the back... but from what I can make out from this one, it sure does look like a non-standard pinout. The picture of the label for sure suggests the PSU is from that era when Compaq (and Dell) used non-standard pinouts on the ATX connectors. Shame, because it's a nice PSU to re-use (most OEM PSUs from that era used Japanese caps only, so they are pretty much bullet-proof).

If it does turn out to be a non-standard pinout, you might also want to give the PSU to your friend to power that motherboard you gave him. Less headaches for him too, should he try to use a regular ATX PSU and wonder why it's not working. 😁 (Or worse, if something blows up, due to the ATX connector being completely different from a standard one.)

He has planty of those, and owns several compaq machines, so he will have psu for sure.
Is it possible for me to find standard ATX PSU, but to fit this case (it is a bit bigger then standard one)?

Would it be possible to rewire the PSU? Does it have standard output values at least?

The PSU does appear to have standard output voltages - i.e. 3.3V, 5V, 12V, -5V, -12V, and 5VSB (5VAux). The only non-standard one I see is 3.3VAux... and that could be a problem, if it's going to the wrong pin. (In fact, if this rail is present, we need to get rid of it from the ATX connector, since it can't be used anywhere.)

Also, from the two pictures provided above, the color coding on some of the wires definitely doesn't seem to correspond to standard colors. Actually, it's a bit weird here: from the 2nd picture, that side of the connector does appear as if it's wired like a standard ATX connector... except again, the wires don't have standard colors, at the very least. From the 1st picture above, though, none or very few of the wires on that side seem to correspond to their proper locations or colors.

As to whether or not it can be re-wired - that will only be possible if you have the right amount of 3.3V, 5V, 12V, and ground wires... and of course the standard PS_ON, PG (power good), and 5VSB... which still begs the question where (if anywhere) is the 3.3VAux rail?

Rather than re-inventing the wheel, perhaps there are PSU adapters sold for this Compaq model (for the PC that is.) Generally these adapters would be to adapt a regular standard ATX PSU to the non-standard ATX format of the motherboard. But since we are doing the reverse, an adapter like that should still work? (Anyone else want to chime in on this?) I'm personally faster with a multimeter and a soldering iron, so if it was mine, I'd just open the PSU, check where each wire connects and re-wire the PSU accordingly.

But you tell us which way you want to proceed. 😉

momaka wrote on 2024-04-05, 08:53:

The PSU does appear to have standard output voltages - i.e. 3.3V, 5V, 12V, -5V, -12V, and 5VSB (5VAux). The only non-standard on […]
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The PSU does appear to have standard output voltages - i.e. 3.3V, 5V, 12V, -5V, -12V, and 5VSB (5VAux). The only non-standard one I see is 3.3VAux... and that could be a problem, if it's going to the wrong pin. (In fact, if this rail is present, we need to get rid of it from the ATX connector, since it can't be used anywhere.)

Also, from the two pictures provided above, the color coding on some of the wires definitely doesn't seem to correspond to standard colors. Actually, it's a bit weird here: from the 2nd picture, that side of the connector does appear as if it's wired like a standard ATX connector... except again, the wires don't have standard colors, at the very least. From the 1st picture above, though, none or very few of the wires on that side seem to correspond to their proper locations or colors.

As to whether or not it can be re-wired - that will only be possible if you have the right amount of 3.3V, 5V, 12V, and ground wires... and of course the standard PS_ON, PG (power good), and 5VSB... which still begs the question where (if anywhere) is the 3.3VAux rail?

Rather than re-inventing the wheel, perhaps there are PSU adapters sold for this Compaq model (for the PC that is.) Generally these adapters would be to adapt a regular standard ATX PSU to the non-standard ATX format of the motherboard. But since we are doing the reverse, an adapter like that should still work? (Anyone else want to chime in on this?) I'm personally faster with a multimeter and a soldering iron, so if it was mine, I'd just open the PSU, check where each wire connects and re-wire the PSU accordingly.

But you tell us which way you want to proceed. 😉

Hm...interesting choice, I would do both. 😁
Damm, I had this PSU open yesterday and didn't check the markings on the board. I will open it now and see if the wires are marked or not.

How can I turn it on? So I can check voltages anyway?
Connecting white one and ground didn't do the trick like on standard ATX

Update1: Maybe adapter would be better as then I don't have moded PSU and it can be used with different board if needed

momaka wrote on 2024-04-05, 08:53:

.. which still begs the question where (if anywhere) is the 3.3VAux rail?

It is the rose wire, pin 11.

I am in a process of marking all the wires I can, just opened the PSU

Update: The rose wire is not connected to the board when using adapter, because pins 11,12, 23 & 24 are excluded on the adapter. So that 3.3V Aux should not be problem

This is what I found:

1: Brown 3V
2: Brown 3V
3: Black GND
4: Red 5V
5: Black GND
6: Red 5V
7: Gray ?
8: Thin Purple FAN_ON
9: Green 5V AUX
10: Orange +12V
11: Rose 3VAUX
12: Thin Red-White FAN-CMD
13: Brown 3V
14: Blue: -12V
15: Black GND
16: Thin White ON-STBY
17: Black GND
18: Black GND
19: Black GND
20: Thin Yellow ?
21: Red 5V
22: Red 5V
23: Thin Brown 3VRS
24: Thin Blue-White FAN_SINK

Four wires are covered with some glue. I managed to remove from two, but not from wire 7 & 20.

Will this help?

I used this layout:

So, can it be re-wired, using to the above info?

According to wikipedia this adapter should work just fine. If wires 11,12,23 & 24 are removed (they are remmoved in adapter) the rest of wires should perfectly match to what I have in compaq PSU.

Am I wrong?

Standard ATX PSU:

I also think the adapter should work. Just make sure the final result at the ATX end going to the motherboard does indeed omit the 3.3VSB and that all of the voltage rails are at their respective positions.

The adapter route should also be much much easier than re-wiring the PSU or re-pinning the original ATX connector... unless you already have a pin extraction tool for those (I don't and I always dread when I have to re-pin even just 6-pin modular cables from one PSU brand to another.)

momaka wrote on 2024-04-07, 07:31:

I also think the adapter should work. Just make sure the final result at the ATX end going to the motherboard does indeed omit the 3.3VSB and that all of the voltage rails are at their respective positions.

The adapter route should also be much much easier than re-wiring the PSU or re-pinning the original ATX connector... unless you already have a pin extraction tool for those (I don't and I always dread when I have to re-pin even just 6-pin modular cables from one PSU brand to another.)

Which one is 3.3VSB from my pinout?

1: Brown 3V
2: Brown 3V
3: Black GND
4: Red 5V
5: Black GND
6: Red 5V
7: Gray ?
8: Thin Purple FAN_ON
9: Green 5V AUX
10: Orange +12V
11: Rose 3VAUX
12: Thin Red-White FAN-CMD
13: Brown 3V
14: Blue: -12V
15: Black GND
16: Thin White ON-STBY
17: Black GND
18: Black GND
19: Black GND
20: Thin Yellow ?
21: Red 5V
22: Red 5V
23: Thin Brown 3VRS
24: Thin Blue-White FAN_SINK

boby wrote on 2024-04-07, 08:47:

Which one is 3.3VSB from my pinout?

Should be the one labeled "ROSE 3VAUX", so pin 11.

Also, make sure the one labeled "23: Thin Brown 3VRS" connects to the 3.3V rail on the adapter. "3VRS" probably means 3V Return Sense... i.e. sense wire for the 3.3V rail. Without it, the PSU may not start or the 3.3V rail might not come out right.
As for pins #8, 12, and 24... these seem to relate to the operation of the PSU fan(??) Not sure how the adapter handles those, so function of the PSU fan should be verified afterwards.

momaka wrote on 2024-04-07, 12:41:

Should be the one labeled "ROSE 3VAUX", so pin 11. […]
Show full quote

boby wrote on 2024-04-07, 08:47:

Which one is 3.3VSB from my pinout?

Should be the one labeled "ROSE 3VAUX", so pin 11.

Also, make sure the one labeled "23: Thin Brown 3VRS" connects to the 3.3V rail on the adapter. "3VRS" probably means 3V Return Sense... i.e. sense wire for the 3.3V rail. Without it, the PSU may not start or the 3.3V rail might not come out right.
As for pins #8, 12, and 24... these seem to relate to the operation of the PSU fan(??) Not sure how the adapter handles those, so function of the PSU fan should be verified afterwards.

Wires 11,12, 23 & 24 are excluded in adapter, they are not connected anywhere. Rest of the wires are.
So I can't do any of your suggestion, unless you know where should I rewire them? 😒

Should I maybe use adapter like this, insted of the one from first post?

boby wrote on 2024-04-07, 13:03:

Wires 11,12, 23 & 24 are excluded in adapter, they are not connected anywhere. Rest of the wires are.
So I can't do any of your suggestion, unless you know where should I rewire them? 😒

Well, as long as pin #11 is excluded (as in, does not continue to go anywhere else from the plug on the Compaq PSU), that's really the most important one.

#12 is "FAN-CMD" ... so nothing no one would miss.
#23 is "3VRS"... which might or might not be an issue (only to the Compaq PSU, not to the motherboard)... but we can figure that out later.
#24 is "FAN_SINK", so again, probably nothing no one would miss.

Basically, do this:
- Plug adapter into the Compaq PSU and test resistance on the output side of the adapter (the side that should plug into the motherboard) to see if you get a nice low resistance (under 3 Ohms) / continuity / "beep" from each major voltage rail (mainly 5V, 12V, and ground) to the same rails on a Molex drive connector of the PSU. The Molex drive connectors are standard and have 5V, 12V, and ground. So as long as these match on the output side of the adapter's ATX connector, then at least we can rest assured that the adapter won't reverse-voltage or put higher voltage on the motherboard to a spot where it shouldn't. After this, plug Compaq PSU into the wall and look for the 5VSB rail and PS_ON signal. 5VSB should measure a nice steady 5V on a multimeter (+/-5%, of course) and it should go to pin #9 on the ATX connector. If it doesn't, rewire the adapter so that it does. For PS_ON, it should show anywhere between 3 to 5V and grounding this pin with a piece of wire to the chassis of the PSU should make the PSU turn On. The PS_ON signal should be found at pin #14. If it's not, rewire the adapter so that it is. Do the same with the -12Vrail.

boby wrote on 2024-04-07, 19:42:

Should I maybe use adapter like this, insted of the one from first post?

That looks like a straight-through adapter, so definitely a NO-GO.

My current adapter is also straight-through.
If it makes any difference, I found out that, I can plug the PSU to the board without adapter. Last 4 pins are not connected, but rest 20 are, so the adapter is fine for sure, as I have same result with it or without it. But I will measure it.

Update1: So all rails shows less then 1 Ohm resistance, so adapter is ok.
When plugged in the PSU shows 5V on pin 9 and 3,34V on pin 11. Pin 11 is not connected to the board as well as 12, 23 & 24.

So I guess, this Pin 11 is the problem, because it is not connected