Might be a power problem to the GPU or maybe something up with the slot, have you tried removing anything else but the 4200 and what's needed to boot and testing it out (with no underclock/undervolt)? Do you also have any other AGP GPUs to do the same with?

The mainboard has a known issue with later (1999 and up) AGP cards that draw too much power.
There are mods to bypass the linear regulator on the back of the PCB and feed the slot +3.3V directly from the 20pin ATX connector.

Do youhave any soldering skill and equipment?

Welcome to the forum btw! 😃

Thanks!

I was about to say that an older Riva TNT2 card works fine.
So it definitely makes sense it’s a power issue.

Yes I’ve got very good soldering skills and equipment. What would the mod look like?

siopoudis wrote on 2021-10-30, 16:24:

Thanks! […]
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Thanks!

I was about to say that an older Riva TNT2 card works fine.
So it definitely makes sense it’s a power issue.

Yes I’ve got very good soldering skills and equipment. What would the mod look like?

I'll look up the mod and get back to you. We have recently had another member with the same problem and it turned out the inofficial instructions provided by Gigabyte connected the wrong transistor to the ATX connector. So I'd rather check twice before giving wrong advice again.

IMO it's just better to leave the card running at 225Mhz instead of modding the board...

Ok, that was quicker than I thought. But the thread I'm pointing to is from April and sadly never had a conclusion:
Gigabyte GA-6BXE REV 1.9 and Voodoo 3 3000 question
Same board, same problem.

The OP attempted the fix inofficially suggested by Gigabyte support (according to a nickles.de article) and it didn't work. Apparently Gigabyte erreneously suggested to connect +3.3V on the AGP connector to the LDO next to the AGP slot while it actually has to be connected to the LDO next to the upper PCI slot.
The OP wanted to try a different LDO with higher current capacity but never reported back.
I suggest you first measure the LDO marked with the green arrow in the picture. If it supplies +3.3V try connecting it directly to the ATX connector's 3.3V pins with a bodge wire. (Maybe add a ~1000uF capacitor for increased stability too? Probably unnecessary.)
Hopefully the board will run stable with the GF 4200 Ti after that.
Ofcourse I haven't tried this myself so I can't give any gurantees.
Fingers crossed!

aaronkatrini wrote on 2021-10-30, 20:39:

IMO it's just better to leave the card running at 225Mhz instead of modding the board...

The LDO is probably overloaded and slowly cooking to death even when the card is underclocked. It's a pretty minor mod that can easily be reversed so in the long run it's most likely the better option when one isn't going to limit themselves to very low power AGP cards.
My two cents. 😉

Ok I’ll give it a go tomorrow.
I see the two points mentioned here are Vout of the 2 LDOs, one 1.5V 5A near the AGP slot and another at 3.3v 7.5A near the PCI.

Why is there even a 1.5v LDO on a 2x AGP slot, I thought those were just 3.3v compatible and not 1.5v like later 4x?

I wonder if the original fix is to convert the 1.5v to 3.3v instead. 7.5A should be sufficient from the 3.3v LDO, right?

I’ll try both tomorrow anyway and report back.

siopoudis wrote on 2021-10-30, 20:49:

Why is there even a 1.5v LDO on a 2x AGP slot, I thought those were just 3.3v compatible and not 1.5v like later 4x?

according to https://www.ertyu.org/steven_nikkel/agpcompatibility.html (which is about the only thing I can find on AGP compatibility that my smooth brain can comprehend), 1x/2x can signal at either 1.5v or 3.3v (and 4x can do 1.5v or 0.8v)

In that case it sounds like a bad idea to connect it to the 1.5v output.

I’ll connect it to the 3.3v LDO and see if that helps.

Thanks for all the help so far!

Ok, mod is now in.

I ended up connecting one of the 3.3v points from the ATX connector, as there's no point tapping all three (they show continuity on the PSU side anyway) to the 3.3v regulator (PCI side).
I tried first without the 2 Voodoo 2 cards connected.

Guess what, it doesn't freeze anymore!

However, it now won't power on when I connect a Voodoo2 card (tried with both one or two connected). The PSU clicks on and off repeatedly.
Removing either the Geforce4 from the AGP slot, or the Voodoo2 from the PCI slot allows the PC to boot.

Now I kinda had this problem before though, but it would stop "clicking" after one or 2 times and then power up just fine. I wonder if that's an issue with the newer type PSU I'm using (Seasonic 400W fanless).
I'm now contemplating how much I really need the Voodoo 2 cards. I don't think there's any games I play that specifically only work with Glide.

Thanks for the update! 😃👍
Could it be you're overloading the +3.3V or +5V rail and some protection in the PSU is triggered? Maybe due to a current spike on startup?

Not sure, this happens when a Voodoo 2 and the Geforce4 are both plugged in. I tried it with just CPU / RAM and these two cards connected and this clicking happens.
Also tried another Seasonic 550W Gold PSU I have and the behaviour is the same again.

I'm not too bothered though, I decided to get rid of the Voodoo 2 cards and stick with the Geforce 4. Went over all the installed games and they all suport D3D. Happily playing Morrowind again 😀

Edit: Forgot to mention that no other connected PCI card triggers this problem. I have a network adapter and a USB 2.0 controller and they both work fine with the Geforce4 and the mod. It's just the Voodoo 2 that does this.

Edit 2: Further small update: the mod seems to be working great. I've now overclocked the Geforce to 300MHz core / 500MHz memory from the original 250/450. Perfectly stable.
I had the PSU do the on/off cycle when I turned off the PC at some point, so this issue is likely related to the new type PSU and not the Geforce 4 / Voodoo 2 combo I suspected before. Resolved by turning the PSU on and off from its switch.
All in all, a terrible motherboard, haha! Can anyone suggest a better one for a Slot 1 750Mhz 100MHz FSB cpu?

Asus P3B-F (Rev 1.04) is highly regarded.
But most later 440bx boards are pretty mature. Apart from Gigabyte anything from bigger brands of the time (Asus, AOpen, Abit, Epox, MSI etc.) with colour coded I/O (indicating a late board) should be a good fit.
Some may need a recap though. Especially Abit is suspect.

Ended up getting an ASUS CUBX-L with a socket 370 CPU at the same speed pretty much.
The wire fix is pretty unstable, powering up and down is a lottery if it's going to happen right.
Removed the wire and it powers up / powers down just fine, so I wouldn't recommend this to anyone. Just get a better motherboard, or a less power hungry GPU.

Thanks for the feedback! 👍
Too bad the mid didn't work out well. I still suspect the PSU plays a role in this but it obviously isn't a clean fix. I won't be suggesting it again.

No problem, thanks for the help!
Asus CUBX-L looks all good with the Geforece 4Ti!