@Radu,

V5-5500 AGP4x


Check it for high size.
http://img518.imageshack.us/img518/8071/agp4xnotchij2.jpg

Oscar

and the story goes on...

Today i tried more...

1. Evilking Voodoo4 card.

First of all, i start with my Voodoo4 Evilking card.
Everybody knows that the card, even if has an AGP4x noch, it's still uses 3.3Volts signals.
In Bios can be only selected the AGP1x and AGP2x; The Epox 8K5A2 board has the hardware monitoring that confirmed to me the AGP Voltage of approx 3.3Volts.

After i study the card, i saw that the A2 pin seems to be connected.... after a check with multimeter, it result that there is no connection between Pin A2 and ground.
So that i came to the ideea to connect the Pin A2 to the ground.
Then  i pluged the card again in the AGP Slot, and start the system. The Voltage Monitroing tells me the AGP Voltage of 1.5Volts.
In Bios the Option AGP4x can be choosen.
System was tested at 1.5Volts, and everything was Ok. No freeze, no BSOD.



2. Voodoo5 5500 - modifyed card.

The Pins 43 that were cuted out onto the graphics board, were ground connected. In order to check the card stability into  the AGP Universal board, i start several test .. everything was OK. No Problems at all, also dual chips work perfect. These test was done in order to see if there is necesary a ground connection into the cuted area.

The Pin 45 from the AGP Slot ( AGP1x and AGP2x ) is connected to VCC 3.3.
Starting with AGP4x, this Pin is no more available. ( KEY )

The Voodoo4 Evilcard has not the Pin 45.
So that my next ideea was to isolate these Pins on AGP Slot of my Epox 85KA2 board. So i did it.
The Pin A2 was connected to ground in order to supply the card with 1.5Volts.
The sistem did not start. Only some beeps...grrrr
Then i installed another card in sistem, in order to see the AGP Voltage and if the Voodoo cards is recognized into the Device List.
The AGP Voltage shown was 1.5Volts, according to the mobo hardware monitor.
But, in Windows, the voodoo5 cards was not recognized.
So that, it seems, that the 1.5Volts, provided from the motheboard is not enough...
There must be a way to force the card to use the 1.5Volt mode.

In the VSA Databook are described the resistor networks that are responsible for the AGP Voltage reference.
One is for 1.5Volt, and one for 3.3Volts. Like Komponent says the simply way is to transform the second voltage network ( of 3.3Volts) into the first. ( 1.5Volts ).

1.5 Voltage reference consist of one resistor network.

1. a 210 ohm resistor conected to VDDQ
2. a 158 ohm resistor connected to ground
3. one 0.1 microF capacitor

3.3 Voltage reference consist of two resistor network.

Firs RC network.
1. a 210 ohm resistor conected to VDDQ
2. a 158 ohm resistor connected to ground
Second RC network.
4. a 210 ohm resistor in paralel with a 560pf capacitor
5. a 158 ohm resistor in paralel with a 560pf capacitor

so that the second RC network must be eliminated ( Position 4 and 5 ) and the 0.1 microF capacitor must be inserted. ( Postion 3 ).
Then it should work @1.5Volts.
Unfortunately i didn't locate yet these components on my Voodoo5 board but i'm keep searching...

Br.
Radu.

Found something :

Under each VSA chips from Voodoo5 5500 are located the following resistance:

32A means - 210 ohm - connected on to VDDQ.
20A menas - 158 ohm - connected to ground.
There is also another Resistance marked 472 (47,2 Kohm )  and one capacitor.

This Area is marked in the Picture !



These components are also on Voodoo4 from 3dfx and Evilking. On the Voodoo5 AGP4x Prototypes ( 5000 and 5500 ) this voltage network is also present.
This is the 1.55V Voltage reference.
But where is the 3.3Voltage reference voltage network...i search on every card, but these components are to find  only once !
I expected to find them twice, for the second network...thats wierd..

nothing new until now....
Still tryng to identify the both voltage network...
but don't worry, there is no reason to give up !

Br.
Radu.

I'll check the status of the TYPE ( TYPEDET ) Pin at voodoo5.
I do not have an dead voodoo5, otherwise i will take the GPU off to make a better analisys. Have somebody a broken or dead v5 in order to check the status of this Pin ?
Another Problem is to find an soldering point on the PCB for this Pin.
Soldering this Pin to ground directly on the GPU's Die is not the best solution.

It's the Third Pin ( C1 ). See pls the picture.



Radu.

Well, i've done some more tests:

The red wire was replaced with a 100 ohm resistor. 
Pin A2 was connected to ground.

Unfortunately, the card works as before, with 3.3 Volts. The behaviour is the same in both Mobo. ( KT333 and K8T800Pro ).

I did  not find the right soldering point for TYPEDET ?

Then, i tried to reduce the AGP Voltage on K8T800Pro.
Currently is running at 1.85 V.
When changing to 1.75V the card start without problems, but the 3DMark2001 return a device error.
The behaviour is the same in dual and single chip mode.
Maye an increased AGP Voltage will bring also more stability .. i don't know this.

That's all so far...
Keep testing and trying... 3dfx hardware has to live on !

Regards.
Radu.

yes, they're shorted together (p2, p3) and are also connected to the top end of r37, c33, r36.
im not able to check vsa-100 #2 - the pins are too damaged :/

but as i already said, i think the typedet pin is not the solution cause it is usually only checked by motherboards with agp universal bus....

i think by connecting pin a2 to gnd, we'll force the motherboard to set the signal level to 1,5v -that might be the reason why it does not work with your card....
as you said, on your powercolor it worked to connect a2 to gnd to set the agp voltage to 1,5V and agp 4x. but we know that the v5 has problems with agp 4x mode (due to more than 1 device on the agp bus) and requires agp2x mode...

a good news: my new riser has arrived, i start doing stuff 2morrow!!!111

€dit:
one thing i can try is to connect the a2 pin at my v5 with one vsa-100 chip - it may work cause there's only one device at the agp bus.

Very interesting news..
especially that the v5 with only one chip AGP4x able is !
To be sure that the card is working at 1.5Voltage, please connect the A2 Pin to the ground.

I see also the problem that we encounter somewhere in the SLI configuration.

I read your thread on voodooalert.de ( ich lese es einfach täglich   ), and i know the whole story.
Thank you for your contribution on this projekt !

Btw. can somebody tell me witch difference is between the V5 AGP2x and V5 AGP4x bios ?
Strapinfo bits ?
The file Size are the same... ?!?
I flash yesterday the v5 AGP4x bios on my modified v5, and the card did not start anymore.

ok, i connected a2 on my risercard to gnd & installed the riser in my 8k5a2 motherboard.
the single-chip v5 is starting with no problems and reported 1,8V AGP voltage - i dont know why it is so high, but i think the problem is the motherboard - it  has some damaged capacitators.
but, as you already have tested, a normal voodoo 5 will _not_ boot up at 1,5V AGP voltage.
so, i think we can be sure that the problem is the sli configuration with 2 chips on one agp bus.

but: i did not tested the pci.exe - i will try soon....
maybe i will find a device - that would mean that the v5 is initialized correctly.

well, to get a solution we should compare the platine layouts on a v5 agp 4x and a usual v5 to find a difference.

as i already said, a very interessting chip is the one above the first agp notch - it is missing on the v5 agp4x and some v5 prototypes....
it would be interessting to see what it actualy does.


€dit:

those v5 agp 4x, do they run at 1,5V or 3,3V in agp 8x motherboards?