My only thought is maybe a weak power supply? What are the specs/age of the power supply you're using?

Good thought ! Need like 25+amps on 5v iirc
Is it a Pentium III-S 512k or non S with 256k cache ? Just curious. Have you tried any other 133FSB cpu's ?

The phrase "until the PC is off for some time" leads me to dying electrolytics somewhere, that manage to operate just well enough once heated.
You can confirm this theory by trying the following: Turn the computer on and don't try to boot, enter BIOS for example. Leave it on for some time, then exit BIOS. I expect it to detect the drive on first try.

konc wrote on 2024-10-02, 07:31:

The phrase "until the PC is off for some time" leads me to dying electrolytics somewhere, that manage to operate just well enough once heated.
You can confirm this theory by trying the following: Turn the computer on and don't try to boot, enter BIOS for example. Leave it on for some time, then exit BIOS. I expect it to detect the drive on first try.

I sort of thought this too, I figured they would probably be in the optical drive (motherboard is recapped). I tried increasing the IDE delay thinking it would give the drives more time to “wake up” but sadly it didn’t seem to do anything.

There’s the slight possibility that the motherboard doesn’t like the low esr poly caps I used, but I’ve never had a problem with that in the past.

Horun wrote on 2024-10-02, 03:09:

Good thought ! Need like 25+amps on 5v iirc
Is it a Pentium III-S 512k or non S with 256k cache ? Just curious. Have you tried any other 133FSB cpu's ?

It’s an S SKU. The same CPU works fine if it’s in the D815EEA (even though it has much worse VRM). I agree the PSU could be flaky but why would it work with a worse motherboard and not with any of the “good” motherboards I’ve tried?

aspiringnobody wrote on 2024-10-02, 09:18:

Horun wrote on 2024-10-02, 03:09:

Good thought ! Need like 25+amps on 5v iirc
Is it a Pentium III-S 512k or non S with 256k cache ? Just curious. Have you tried any other 133FSB cpu's ?

It’s an S SKU. The same CPU works fine if it’s in the D815EEA (even though it has much worse VRM). I agree the PSU could be flaky but why would it work with a worse motherboard and not with any of the “good” motherboards I’ve tried?

From experience, don't assume that the power supply is good because it works with one motherboard; it can be weak and work with a combination that it is just barely good enough for, then fail when used with another where the power demand is just over what it can deliver.

Repo Man11 wrote on 2024-10-02, 13:00:

aspiringnobody wrote on 2024-10-02, 09:18:

Horun wrote on 2024-10-02, 03:09:

Good thought ! Need like 25+amps on 5v iirc
Is it a Pentium III-S 512k or non S with 256k cache ? Just curious. Have you tried any other 133FSB cpu's ?

It’s an S SKU. The same CPU works fine if it’s in the D815EEA (even though it has much worse VRM). I agree the PSU could be flaky but why would it work with a worse motherboard and not with any of the “good” motherboards I’ve tried?

From experience, don't assume that the power supply is good because it works with one motherboard; it can be weak and work with a combination that it is just barely good enough for, then fail when used with another where the power demand is just over what it can deliver.

I’ve ordered a couple of 300w bestec psus from vintage gateway PCs just in case (30A 5V, 180W 3.3V+ 5V). I’ll take apart the one in there and check the caps tonight.

I did check the 5V rail under load and it was 5.05v at the molex connector.

Edit: I took the Startech.com PSU that is in the PC (circa 2012) out. No caps that are (visibly) bad. It's rated for 50A on the 5V line (I remember putting it in this PC because it is by far, the most powerful "retro" PSU I own). I took the opportunity to lube the fan -- but I doubt the PSU is the issue. I'll try swapping it with the 300W Gateway/Bestec one when it arrives but I have a feeling that will just end up being a downgrade. I hadn't taken the Startech.com one apart before but it seems to be well built.

I tried installing windows 2000, got numerous read errors while setup was trying to do the initial copy (they were all resolved, eventually, by repeatedly retrying...). However, on the first reboot (off the hard drive) I get various errors. I think this board is trash. Why didn't Intel make a single Tualatin motherboard? It's such a joke. I've spent hundreds of dollars on junk motherboards that all supposedly have a good reputation. Not one of them has worked.

There are good Tualatin boards but not all like those 1.4Ghz S cpu's with 512k cache. Has to do with bigger onboard cache I think and BIOS or something does not like it. Have some good soc 478 that will run everything 800Mhz but not the 1Mb "E" cache ones. Think there is also an issue with Pentium Pro soc 8 and the 1Mb cache cpus's on many motherboards iirc

Hmmm. This morning it hung up detecting IDE, but it was the primary channel that was the problem this time. Nothing I could do seemed to make it work after that.

I’m gonna scrap it. Sucks since I just wasted $50 worth of caps on it. I tried a coppermine cpu and got the same behavior.

So did you try another PSU or not yet and you are going to scrap the motherboard before even trying, besides everyone telling you so, and after you have already ordered "a couple"?

Also because "nothing I could do seemed to make it work" doesn't say much, if you haven't done it already disconnect all other devices and leave it with just one known good HDD. It may be that one of the other devices is causing this behavior.

aspiringnobody wrote on 2024-10-03, 02:10:

It's such a joke. I've spent hundreds of dollars on junk motherboards that all supposedly have a good reputation. Not one of them has worked.

They're 25 years old.
Recapped or not, they're ancient.

Have you cleaned the board?
Inspected it?
Probed the power transistors for awry voltages?
Checked the other components?
It's got 5 pci slots. Tried a sata/ide card?

aspiringnobody wrote on 2024-10-03, 02:10:

Why didn't Intel make a single Tualatin motherboard?

Intel D815EEA2U has Tualatin support and works with the S CPU on specific BIOS versions.

konc wrote on 2024-10-03, 11:48:

So did you try another PSU or not yet and you are going to scrap the motherboard before even trying, besides everyone telling you so, and after you have already ordered "a couple"?

Also because "nothing I could do seemed to make it work" doesn't say much, if you haven't done it already disconnect all other devices and leave it with just one known good HDD. It may be that one of the other devices is causing this behavior.

I tested it with a modern 1200W PSU which obviously isn’t ideal (still doesn’t have the power necessary on the 5V rail), but is all I have that could possibly power a tualatin. I also got out my oscilloscope to check for excessive ripple on the 5V rail with the Startech.com PSU. It was fine (and hovering just above 5V). It also behaves the same with an 800MHz coppermine. I tested multiple IDE HDDs and another SD-to-IDE adapter. I also tested a fresh SD card since sometimes if they get formatted incorrectly the SD-to-IDE won’t recognize them. I took everything out, including the AGP GPU and tested with just a RAGE II+DVD (PCI). Tried with a promise pci ide card, and the original SD-to-IDE is detected immediately (if I could boot a CDROM from the PCI card I might have considered leaving it like that, were it not for the fact that the motherboard also hangs on shutdown randomly and doesn’t display anything out of my known-good Radeon 9600xt 128MB — even though it works fine with my Radeon 9600xt 256MB). Swapped in a known good 128MB stick of PC133. I also programmed a spare EEPROM externally and changed out the BIOS Rom. I also removed the motherboard and checked around the chipset and IDE ports for suspect traces and VIAs.

If you can think of anything to try that I haven’t already I’m open to suggestions. I’m thinking the chipset is bad, and even if I could source another one I don’t think it’s worth trying to swap the chipset without a BGA rework machine. I don’t think I have the proper stencil either.

y2k se wrote on 2024-10-03, 12:11:

aspiringnobody wrote on 2024-10-03, 02:10:

Why didn't Intel make a single Tualatin motherboard?

Intel D815EEA2U has Tualatin support and works with the S CPU on specific BIOS versions.

I’ve never been able to find one of those for sale. While it has VRM that (maybe) is better than the D815EEA that works fine in this machine for me, the EEA2U is also not rated to supply 1.4GHz chips.

I also wouldn’t mind having a D820LP motherboard (I think they were Dell OEM only in the XPS B-Series. I actually bought a whole XPS B773r from eBay to try to get the board, but even though the r is supposed to denote the socket-370 motherboard the one I got ended up having slot-1).

aspiringnobody wrote on 2024-10-03, 12:14:

If you can think of anything to try that I haven’t already I’m open to suggestions. I’m thinking the chipset is bad, and even if I could source another one I don’t think it’s worth trying to swap the chipset without a BGA rework machine. I don’t think I have the proper stencil either.

Until now we didn't know all these and we were trying to stop you from tossing the board, for example you never mentioned that you tried a different PSU.
Now it does look like it's the only remaining culprit.

It's far more likely to be one of the support chips around the chipset.
Try a pci ide/sata card.

myne wrote on 2024-10-03, 12:56:

It's far more likely to be one of the support chips around the chipset.
Try a pci ide/sata card.

PCI IDE works, but as far as I know there isn’t a way to boot a CD from an add-in card on this board so that’s as far as I got. I’ve got a few Promise cards and a couple of Highpoint ones.

I’m hesitant to run the CD-ROM off of the board because at some points I’ve been having problems with the secondary channel as well.

I’m wondering if this is one of those rare cases where I’ve replaced a high ESR cap with a low ESR cap and it actually matters. There don’t seem to be any caps that area of the board anyway.

I tried forcing PIO mode and it still didn’t detect the drive. Only thing I haven’t tried is a CF card, but I’ve never had good luck with those in a more modern PC.

I’m tempted to pull out my CUSL2-C start recapping it. It was flaky before so I never proceeded any further.

Have you tried different memory? I've had modules pass memtest and then still give problems that didn't really seem ram related...until I swapped them out and all was well