Problem upgrading with a modern ATX PSU on old Presario (incompatible wiring)

[tsundvis]

Compaq Presario 8568EA

S/N 4D25KJS8R03H

Purchhased a new CORSAIR CX 400W  ATX12V 2.2 / EPS12V in order to replace the old one in my computer, that had become noisy. Unfortunately when power up the Presario, nothing happens! The reason can be seen from the attached picture, where one obvious inconsistency is at the pin 8 & pin 17.

"An old cheap PSU may not have "Power OK" circuitry and might just connect pin 8 to +5V. Modern motherboards may have booting problems without functioning PWR_OK signal."

Unfortunately, it seems the Presario isn't using the formfactor of an ATX PSU either, since the holes for the mounting screws are different. However, that's a minor problem, the big problem is that it's motherboard is incompatible with the wiring of a modern ATX PSU!

After adding a more modern GPU to this Presario computer, there's a need for more power than the stock ones delivers.

 Compaq Series PDP116P
Part NO: 243890-001 (Replace with Compaq Spare NO: 244166-001)
MODEL: HP-U250XC3 rev: d
S/N: CT:54B6B0BM5N471M
Input: 100-240VAC 3.6A
Output: 250W MAX

What should I do? Should I rewire my new Corsair CX400W PSU to fit the old incompatible Compaq Motherboard 0784h, however I doubt I can move the contact pin from slot 17 to slot 8?

Please advice.

[old_geekster]

Here is the Product Specifications page for your computer.  Here is what it says about the PSU:

Power Supplies
Chassis / Power Supply	[Core Requirment]
	- 235 Watt Power Supply (Micro-Desktop) Prowler (includes PFC support)
	- u-ATX form factor
	- Needs minimum of five (four HDD/CD and one FDD) connectors*
	- 235 Watt Power Supply (Micro-Desktop) Prowler (includes PFC support)
	*marketing request to have 250W can support six (five HDD/CD and one FDD) connectors.

[PC_Tester]

I would try another PSU from another manufacturer and see if it works.

[tsundvis]

Thanks for the link to the Product Specifications for my Compaq Presario Desktop PC 8568EA, but it doesn't help me further at all.

I want to use a PSU with more power than the stock one:

Compaq Series PDP116P
Part NO: 243890-001 (Replace with Compaq Spare NO: 244166-001)
MODEL: HP-U250XC3 rev: d
S/N: CT:54B6B0BM5N471M
Input: 100-240VAC 3.6A
Output: 250W MAX

Please advice an upgrade PSU with at least ~350W, so that I can run a new AGP graphics card.

[tsundvis]

PC_Tester:

That's what I actually did with the Corsair CX400W!

Here's what they say about it:

Supports the latest ATX12V v2.2 standard and is backwards compatible with ATX12V 2.01 systems.
http://www.corsair.com/products/cx/default.aspx

All PSU I can buy today follows the ATX standard:

http://www.formfactors.org/

If you look at the photo above, showing the 24-pin connector, you should see one important discrepancy with the pin 8 and pin 20 (with the correct pin numbering according to the image below). This leads me to believe, that it is not possible to use any standard ATX PSU at all. Can you verify that incompatibility.  What I want is a solution to replace with a PSU of at least ~350W for a new AGP GPU.

Here is the standard pinout for ATX:

http://mynetimages.com/956789a98a.gif

[tsundvis]

I need a new PSU upgrade, that has more juice than the stock PSU and it's equal replacement of 235W only.

Spare part replacement offering a measly 235W power:

http://mynetimages.com/15cf824c99.jpg

P.S:

I've recently upgraded the stock GPU nVidia NV25 128M GF Ti4600 TVOut with a SAPPHIRE HD 4650 512MB DDR2 AGP. Sapphire recommends a 400W PSU through a dedicated PCI Express 6 pin connector, since the AGP 4x bus cannot deliver the needed +12V power. I've read that this PCI-E 6 pin connector is specified to deliver 75W.

But I wonder if this new ATI Radeon card isn't at least as energy conservative as the old nVidia Geforce NV25, considering a much newer semiconductor manufacturing process. For wild gaming (as much as this P4/Willamette/2000/400/S478 can move) or watching HDTV, I might just feed the GPU from an auxiliary PSU capable of handling 75W through a PCI-E 2x3 pin connector. Otherwise, there might not be much of a power consumption difference?

[duup01]

Hello,

I have the same problem with my presario and his powers supply, i found this site. what do you think of it.

Would it be a solution?

http://www.bizrate.com/power-supplies/products__keyword--compaq+presario+power+supply__start--40.htm...

(srry my english is not so good)

kind regards,

Duup

[tsundvis]

Duup:
Thanks for the link to this e-commerce site. I've just searched the site, but unfortunately didn't get a match for neither the desktop "Compaq Presario 8568EA", nor for the PSU model numbers "243890-001 / 244166-001 / HP-U250XC3". It would be a bad gamble to order any PSU from the US, risking to end up with the fuzz of returning a shipment from Europe.

I've just got a RMA OK from the shop where I bought the Corsair CX400W PSU. I've now sent that back with the message that my computer is incompatible with the standard ATX PSU.

I'm still counting on HP support to try harder verifying this problem and proposing a working solution.

[tsundvis]

Pinout for Power Supply Assembly (PN 243890)

The power Cable Diagram reveals the incompatible P1 connector, which is using a Compaq proprietary wiring.

My conclusion therefore is that a standard ATX PSU cannot be used with the 8568EA Compaq Presario.

[gkdiamond]

I wouldn't try plugging a modern ATX power supply into your Compaq's motherboard again. Looking at the diagrams you posted I can see that you are putting 12V on a 3.3V input and can easily damage (as in fry) your motherboard.

See this thread on Ecoustics for possible solutions.