Help with power supply for old Compaq system

[clinthammer]

So I plan on installing a geforce 4 mx420 in my sister's old system. However, the requirements for the new pci video card is min 250w psu. The current psu in the Compaq is max 110w.

So I plan on buying a new 300w enermax psu. However, I noticed that the current psu has 3 connectors going to the mobo. P1, p2 and p3. P1 and p2 go side by side on J12 while p3 goes on j20.

Problem is the 300w enermax has only two cords that connect to the mobo. Do you know if I can use this on the compaq or is there a special psu i have to purchase?

Diagram of the mobo and system is below:

http://h18000.www1.hp.com/athome/support/msgs/4951/bd3jm.html
Any help is much appreciated.

Thanks.
CD

 

[jschuk]

There is an article on Overclockers.com that talks about putting a generic PSU into a Dell and Dell also uses a proprietary connection. The article also has a link to a site that sells adapters. Good luck.

 

[Mday]

do you already have the video card? if so, pop it in, see if it works.

you need an AT power supply. and compaq may actually implement a proprietory pinout for the power plugs. this means that the voltages supplied by each pin on the connectors may not be the same as the AT power supply specs.

http://www.pcguide.com/ref/power/sup/parts_Motherboard.htm

that link provides a link of the pinouts for standard AT and ATX powersupplies as well as any extensions they may have. you may learn some more if you read the page, and other parts offered by pcguide. support them if you find this information useful =)

companies who make their own proprietory parts have been known to go outside of the specifications to offer more power to their systems. this may be what the third plug may be doing. if you have a multimeter, use it to find what voltages are going to each pin of all the connectors.

now, if you use the multimeter, and determine that the powersupply is indeed proprietory which it most likely is, get a new power supply, most likely AT, and splice the wires. you'll have to cut the connectors off the existing proprietory power supply. remember what wires go where though.

and, yes, this is much more effort than just building a new system for her.