Are you sure that the other PSU is really good?

When I built my makeshift power supply tester, I found 3 of the first 4 PSU I tested to be seriously out of spec.

I'll try another one when I get home. The original PSU is a modern Corsair, so I didn't think it was the problem. The next one I tried was a generic 350W from BITD.

Now it's back to booting into Windows, but the splash screen delay is long, and the shutdown from Windows is long.

Tried another PSU, and now I'm back to the "Operating System not found" error. I'm beginning to think that this has to do with the caps because I've tried at least two different versions of the major components.

A friend of mine ever brought in a Celeron 300Mhz and the mainboard was riddled with bulging caps. It would rarely make it to Windows, sometimes it would just display a black screen of give fault codes.
Does your system give any beeps/fault codes?
Can you turn off the BIOS splash screen? Might hide extra info.
Did you try another keyboard/mouse or run without? Weird PS/2 IRQ conflicts with controllers do happen.

http://hw-museum.cz/data/mb/pic/Intel_SE440BX-2_F.jpg
7 caps, wont hurt replacing as a diagnostic step

Yep sounds like it could be the caps, but I’ve seen similar behaviour recently with a machine of mine when I put an IDE to CF adapter as a slave to the main drive - moving it to the master on its own IDE port sorted it out.

You didn’t mention using one but I just thought I’d throw it out there.

Thanks again for all your suggestions. I am running off regular 3.5" IDE drives, although I am going to try a CF-to-IDE adapter just to see if it makes a difference. I was hopeful that a new PS/2 keyboard might make a difference, but unfortunately no. I'm pretty sure I can't switch off the splash screen, but there is a log of errors accessible from the BIOS (forgot to mention). A floppy error is logged. However, I still have the bootup problems even when I unplug the floppy cable and disable the floppy in BIOS.

I don't know how to solder, but I may practice on some old PCBs before tackling a cap replacement on the BX.

Good luck with it. Replacing caps is pretty easy but is a chore for someone like me who isn’t great at soldering - I bought a new iron recently and better quality desoldering braid and what has made a difference.

boxpressed wrote:

I don't know how to solder, but I may practice on some old PCBs before tackling a cap replacement on the BX.

It's a very useful skill.

As I was doing some tidying up today, I discovered that I had another SE440BX-2, the one with the built-in Yamaha audio. I dropped it in as a direct replacement and -- experienced the same odd behavior. Too long on the splash, taking too long to shut down from Windows, etc.

The only thing it could be would be the PSU or the HDD. It was the HDD. I replaced it with the one I thought was dying, and everything worked as it should. So I don't know if this HDD will begin to malfunction again, but I'm 99% sure there's nothing wrong with the motherboard. Glad the Intel rep for quality is still there.

Thanks to everyone for their suggestions.

Returning to this old thread for some welcome closure. The build continued to be flaky after the new HDD, and I was at my wit’s end trying to diagnose the problem. It was a power issue after all, but the problem wasn’t the PSU. It was this stupid molex extension that I kept using with each iteration. Because I was using the same case, I always needed it because I kept putting the HDD in the same bay.

Anyway, I’m probably the only person who will ever have this problem, but don’t overlook these crappy extensions if you have intermittent errors that point to power issues.