Are they ATX? There shouldn't be such a requirement...

Yes both boards (and the power supply) are ATX, and both boards use the 20-pin connector.

I wouldn't have thought a Tualatin board of that vintage would require the -5V, but I downloaded the manual and there is indeed a -5V connector on the ATX plug.

http://www.unitycorp.co.jp/support/download/m … 0/tusl2_c_e.pdf

look on page 40

also what are the current ratings for the 3.3V and 5V rails on your PSU? Is it possible that it just doesn't put out enough power on those rails? Modern machines take most of their power from the +12V rail, whereas an older one like a P3 uses more from 3.3V and 5V so I wonder if your motherboard is just trying to use more power on the lower voltage rails than is available...

According to the power supply label:

+3.3V: 28A
+5V: 40A
+12V: 17A
-5V: 0.3A (there may still be a -5V rail in the actual power supply, but the wire connecting to it is non-existent)
-12V: 0.8A
+5V Standby: 2.0A

Seems like it should be plenty for a PIII, no? On the P2B board I'm using a Celeron 400.
Both boards refuse to POST even with the most minimal configuration (i.e. if no graphics card is plugged in, there should be a "video error beep" but that doesn't happen either). If I plug in my hard drive, the HDD LED (on the case panel) remains lit.

well yeah I would think those current ratings are fine.

Have you got a different power supply to try? Not necessarily with the -5V, just any pwer supply to rule out the one you are using as an issue.
If that doesn't work I guess that you might have to track down and older one with the -5V connected, otherwise maybe both your boards are just DOA. 😒

PSU defective?
And I don't think the TUSL2-C needs -5 volts, iirc that was an ISA thing, which the board doesn't have anyway.

And could you post a pic of the unit (so it displays it's stats) or write it's FULL stats on here? Including brand name and PSU model number

Turns out the TUSL2 board is a dud.
I managed to get my P2B to boot on the same power supply, just swapping out the RAM stick and changing the FSB jumper to 66 MHz.

Don't really trust buying old hardware on ebay anymore, ugh

Pippy P. Poopypants wrote:

Turns out the TUSL2 board is a dud.
I managed to get my P2B to boot on the same power supply, just swapping out the RAM stick and changing the FSB jumper to 66 MHz.

Don't really trust buying old hardware on ebay anymore, ugh

Buying 2nd hand is ALWAYS a gamble. You can minimize the risks (like looking for scratches, bulging caps, his feedbacks etc) but can't make the risks 0.

-5v is only used by some particularly old ISA cards. It is kinda rare.

swaaye wrote:

-5v is only used by some particularly old ISA cards. It is kinda rare.

True that. I agree with having a PSU which has -5v is handy, but I wouldn't consider them more valuable then a later -5vless PSU. Still, if the price is low enough and the rest identical, I'd prefer one of the -5v ones (though I "think" my stock is high enough for me top not have to bother buying any more at this time).

I could never get either of my TUSL2-C boards to power up using antec power supplies, but they worked fine with the other branded ones I have.

Maybe try a different psu?

tannerstevo wrote:

I could never get either of my TUSL2-C boards to power up using antec power supplies, but they worked fine with the other branded ones I have.

Maybe try a different psu?

Interesting, I'll try that once I have some more time this week. But I'd figure if any PSU can generate the required voltage and current levels it should work fine.

True that. I agree with having a PSU which has -5v is handy, but I wouldn't consider them more valuable then a later -5vless PSU. Still, if the price is low enough and the rest identical, I'd prefer one of the -5v ones (though I "think" my stock is high enough for me top not have to bother buying any more at this time).

You can always build a regulator circuit using a linear regulator IC (the LM337 is a good negative voltage regulator) and a few spare capacitors and resistors to generate the required voltage. Just feed an extra -12V wire from the power supply into the input and it should work. But yes if you have a ton of old ISA cards a power supply with -5V would come in handy.

Well, tried it with a different PSU (this time I managed to find one of my older ones that has a -5V lead) and still not working. Bah looks like I'll have to hunt down the vendor for a refund.