Oh, I didn't connect anything to the on board audio output. I only plugged in a speaker to the header on the motherboard.
My success so far is minimal. Basically with the TX650M everything powers on, but the speaker doesn't beep and there's no post
With the Thermaltake TR2-500, sometimes it posts, sometimes it doesn't and a few times it didn't power on, the fans spun up for a quick second and then nothing.
With the Enermax Coolergiant, it posted a few times, while a few other times it didn't post.
With the Thermaltake and the Enermax when it all powers up, the speaker beeps once even if there's no post.
I am waiting for a VGA to HDMI converter (the Atlona HD-500 (used) that has been discussed on this forum and which was also sold under the Startech brand, but there it has been replaced by a less DOS compatible model) to see if maybe the monitor I have with a VGA input just doesn't like the Voodoo 3 VGA input signal.
The build I'm going for is a Pentium 4 2.0 with a Voodoo 3 2000 . This why I got this board, it has universal AGP & 4 pin CPU power connector. The seller says that he has tested the board with a Voodoo 5. Again, he didn't give me an exact model, but he used an OCZ 550w PSU (obviously discontinued).
I also tested to see if it works with a Riva TNT2 (I think it's a 2) and I get the same behavior.
I actually have 2 of these boards. One which I bought sold as new old stock (aka never used) and one which has been completely recapped (the one the seller tested withe the Voodoo 5 & OCZ 550w PSU).
I have another board with the same chipset made by ECS but which doesn't have the 4 pin CPU power connector, nor a molex connector on the board for 12v power. That board posted just fine with the Voodoo 3. However it also didn't work with the Corsair TX650M, which I had expected.
The ECS board came with a Lite-ON PSU which is weird. I mentioned above that it has a 6 pin power connector (at least I think it's a power connector) which I have no idea what it's for. Unfortunately the layout of the Asus board makes it impossible to plug that 6 pin connector into the 4 pin CPU power connector and I don't even know if they're compatible. Also this Lite-ON PSU seems to have a really low power output, it says 130w DC output on it.
I will retest the PSUs that I have when I get that VGA to HDMI converter delivered (except for the TX650M, that one clearly doesn't work).
Again, strange behavior of this board with all of the PSUs I have. Even on the Thermaltake (ATX 2.0) and Enermax (ATX 1.3) which should work it sometimes doesn't post. Either with everything plugged in or with nothing but the board power (ATX & 4 pin) plugged in.
If you can share the serial/SKU number of the CX750M you have, maybe I'll find one used it new old stock or something. I'd still trust that PSU over the ones I have. Could be wrong in thinking this though.
While I did build and tinker with PCs around the time when these components were new, I don't remember much from the era and I had little information about what was a good or bad component at the time. It feels weird that while I can put together a modern/current PC without much issue, I find myself stumped by some of the issues with older PCs. I never had any source of info back then on what to do so the finer details were lost on me. Feels weird not knowing things and I would say it's part of the fun, but it gets expensive really fast which sucks.
Edit: oh damn, I just saw that the CX 750M you bought didn't work. Damn. Well, the hunt for a PSU continues.
Oh and if anyone can recommend a good aftermarket socket 478 cooler, I'd appreciate it, new or old. I remember that the Pentium 4s got really hot with their stock coolers.