Hi guys I originally posted about this on a repair forum, but someone replied quoting this forum so I decided it would be better to ask here as there is so much retro hardware expertise here

So, to save a lot of typing this is my orignal post(s)

Hi guys
I picked this up at the flea market on Sunday, €2

At first I was not sure exactly what it was as it is marked 3dfx Voodoo V CV350 Ver1.0 32M, but the 3dfxlogo was enough to persuade me to buy it - oh, and the price!

Turns out this is a Powercolor Evilking Voodoo 4 4500!

Anyway it does not give a picture - it also hangs the PC on POST card code either 41, 42, or 43. It beeeep bip bip to say no graphics card

Two of the wires to the cooling fan are broken off - how do I tell which way round they go?

The GPU just gets warm, not hot, even without the fan

There are no VRMs on this but there is a US1150CM LDO which has 3.3V on pin 5 and 2.7V on pin 3, or very close to that, so that looks OK. The LDO output pin 3 reads 256R to ground

I don't suppose I would be so lucky that it will not detect if the fan does not spin up? it is a 3 wire one.

This was a really nice find I think, it would be rather excellent if I can get it to work

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Yeah I see I may have fell foul of this

'All Banshee, Voodoo3 and Voodoo5 AGP Cards are 2xAGP 3.3V only!
Do not use in modern 4x/8x AGP 1.5V only Motherboards!
Failure to comply can cause damage to both the Card and the Motherboard!
Consult your Motherboard manual for 2xAGP 3.3V support before use!

Only the retail 3dfx built Voodoo4 4500 AGP is 4xAGP 1.5V capable.
(the Powercolor Evilking Voodoo4 and the rare 3dfx Voodoo4 4500 "L" Shaped variants are confirmed to be 2xAGP 3.3V only)'

And this
'Voodoo banshee/3/5 agp cards only work with 3,3v agp slots so be careful with newer boards. socket7/slot1/slotA/s370 boards are usually fine. for socket A the limit seems to be a board with via kt333A chipset (but still check it). kt400/nforce and higher are not compatible with 3,3v agp cards.
Intel boards for p4 cpu's are not compatible at all. Only some p4 boards with SIS chipsets are know to work (check before trying).'
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I had it plugged in to a P4 Socket 478 – Asus P4S533-X

I do have another AGP card with the two slots in the AGP connector that does work in this board. Also the US1150CM LDO on the Voodoo 4 had 3.3V coming in and 2.7V going out and according to the datasheet that is exactly right, so it seems the AGP slot provides 3.3V

I do hope I have not damaged the voodoo 4, assuming it was working previously. I have a few more AGP Motherboards at the workshop but now I am a bit uncertain which would be compatible, One is a Gigabyte GA-5AX SS7 board. I'm sure that must support 2x AGP 3.3V, but Vogons did not mention SS7

I would really like to see this working - such a rare find these days....

PS Oh yeah I spotted the resistor - it does appear to be a mod of some sort

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So can anywone advise:
Should this work in my Asus P4S533-X?
Should it work in the GA-5AX?
How can I determine which of the two broken fan wires goes where - it seems to be polarised +ve -ve as I can see semiconductors on the fan motor?
Would the none powered 3 wire fan stop it from detecting (safety feature)?
What about that resistor that has been added - is it a manufacturers mod/botch/cobble?

Cheers guys