Look over every single tiny component and every pin\leg on each of the chips. Often times the legs on the large chips get dented or crushed and will touch other legs which causes problems. Straightening them can be a pain, but its a fairly easy fix (I usually use a razor blade or something else that is super thin). Just be careful not to actually break one if it is bent. The next most likely cause is a broken tiny SMD capacitor\resistor. Look over the card slowly and carefully... I've overlooked missing SMD caps three times before finally noticing them. They're tiny but they can usually be replaced with a steady hand and some soldering experience. Figuring out the correct value is likely to be nearly impossible, but a lot of times it isn't as important as just getting something on there.

EDIT: Also, its a good idea to thoroughly clean the card too. I usually use a bit of isopropyl alcohol on a toothbrush and just scrub every inch of the card then let it dry. Using a pencil eraser to shine up the PCI contacts can help too.

Pabloz wrote:

>>But how do i know which brand of memory has to be replaced? ISSI or Alliance?

If you have the scrambled screen under pure dos or just Windows it may be one of the ISSI chips connected to the Alliance GPU, if the scramble only occurs running 3DFX software it may be the alliance chips connected to the 3DFX chips.

Pabloz wrote:

>>How to i know if its not the memory but one of the 3dfx chips the one faulty?

If you can start any 3dfx software without getting errors the chip may be, at least partially, functional, otherwise you might get an error message after starting any 3dfx functions.

Pabloz wrote:

>>How to i know if its not the memory but the alliance big chip the one ruined?

There might be no video output at all, but only a beep code stating there is no video card found during POST.

i am checking capacitor by capacitor with a picture i found online

but i think its one of those memory chips.

the card gives artifacts on DOS. NOT SURE if in 3d since in 3D you also use 2D...

what happens if i remove one ISSI chip at a time with hot air? the card should work without 1 chip...and should work without two ISSi chips...right?

by removing one by one and testing the card.. i might get lucky?

You could also have a bad solder joint one one or more of the chips and legs of the chips.

I have a Voodoo 2 12MB card where one of the 3dfx chips has most legs loose on 2 sides.

I haven't gotten around to fixing it because
1. It will take a long time to manually resolder all of those legs
2. I have other projects I am more interested in.

I really doubt the card will work at all if you completely remove one of the RAM chips.

i have a question for someone that knows about memory specifications

the memory is IS41C16256-35K
but i found online a seller with IS41C16256-60K

what is that 60K? can 60K replace the 35K ??

sorry to ask. i have zero knowledge about SOJ memory chips

I believe the 35 signifies the access time in nanoseconds with k denoting a specific model in a series of memory chips.

If it is indeed a 35ns memory chip you can only replace it with chips with the same access time or lower. 60ns would be too slow.

What CPU are you using?