can't get pentium 3 systems to work

[jakeblake]

Hey there I've been trying to piece together a low power system to run in my car, based on socket 370 pentium 3. I have a plethora of hardware, but no matter what configuration I try I can not get the thing to power up, a fan to spin, a light to turn on, NOTHING!!!!

This is what I am working with:

Intel 815EEA motherboard from ebay ("working OEM pull")
Foxconn(?) motherboard with Intel 810 chipset (pulled from old Dell computer at work)
380 watt RaidMaxx power supply (brand new)
250 watt Athena Power supply (brand new)
677 mhz Pentium 3 (was on the Foxconn)
800 mhz Pentium 3 (old one I had lying around)
2x256mb pc133 dimm (tested working)

Note: using either of the power supplies on the Foxconn motherboard causes a high pitch noise to come from the power supply when the 20 pin connector is plugged in.

What could I possibly be doing wrong? My only guess right now is that both motherboards are bad.

[edit] When I short the green power wire with a black ground wire on the 20 pin connector of the power supply when it's plugged into the motherboard, the fans as well as the motherboard LED on the Intel motherboard turn on. It does not beep. The front panel connector, where the power switch would plug into, does not turn the power supply on.

 

[jackschmittusa]

If the power switch does not turn it on, the +5v is not going through the mb.

 

[KGB]

Jake,

Welcome to the Forums! :beer:

Regarding the Dell board, DO NOT try to power it up using a standard ATX PSU.
Even though the MB power connector looks similar, the pinout on the Dell is different.
This is why you hear the noises when you try. You will need the Dell PSU to use this MB.

First, remove everything from the case and setup on a non-conductive surface (cardboard, AS bag, etc.). Use a scewdriver to momentarily short the the MB pins instead of the power switch. This makes it easier to swap things unril you find a combo that works.

 

[jakeblake]

Yeah...guess I'm out of luck on the Dell board then. I have all the parts sitting on a large mouse pad, shorting the front panel pins gives me nothing. I can only get power when shorting the 20 pin connector, but even then, no beep.

Maybe these old socket 370 boards don't work with the new ATX12V power supplies?