Tseng Labs ET 4000W32i 1Mb video corruption

[Alex_Baker]

I was not able to get snarf to work, kept getting and error 1, but I did get screen thief to work.

Here is what I got.

[fzabkar]

To me, that means that the RAMDAC is not at fault. The problem must be happening when data is written to DRAM.

FWIW, these old cards had a "wait state" jumper. Perhaps one of those hard-wired, unpopulated jumpers at the LHS of the PCB selects this option (JP5 and JP6).

https://stason.org/TULARC/pc/graphics-cards/U-Z/UNIDENTIFIED-XVGA-ET-4000.html

Is JP2 meant to be open, or must you select either 1-2 or 2-3? It might be an idea to trace the pins to the ISA slot to see where they go.

[Alex_Baker]

JP2 is connected to IRQ2 on the ISA slot, left is open right is closed. Other than that there are no other jumpers on this thing.

[fzabkar]

JP2 is connected to IRQ2 on the ISA slot, left is open right is closed. Other than that there are no other jumpers on this thing.

At the top left corner of the card are 2 unpopulated jumpers. I suspect that the 0WS / 1WS jumper has been preset to 0WS by a hardwired trace. I'm thinking that the trace could be cut and the alternative pin selected by installing your own header.

[Alex_Baker]

You are right. The one labeled JP5 is connected to one of the select pins for IC 5C, which is a "dot frequency generator" for graphics applications, probably don't need to mess with that. I can't tell where JP6 goes.

There are also two more unpopulated jumpers underneath the main IC labeled JP 7 and JP 9, it's impossible to guess what they may be.

I guess I can try adding jumpers and testing different combos. But I don't know how the jumpers could be my problem, shouldn't the card work as it is?

Perhaps another clue is the fact that this card looks like it spent some time bouncing around in a bin of other electronics given the scratches and bent lead-tails on the back. Maybe the old owner gave up on it.

[fzabkar]

Perhaps it's time to give up and try a different card? I mostly used Trident cards during those days.

IIRC, the only other thing that was configurable was shadowing of VGA BIOS in RAM. I think Chips & Tech chipsets had this feature.  I can't see how this would change anything in your case, though.

Edit:

One more idea. Does your motherboard have a turbo mode? Perhaps you could reduce the speed, just in case the card is too slow for the CPU.

Edit#2:

Here is the ET4000 datasheet:

https://mirrorservice.org/sites/www.bitsavers.org/components/tsengLabs/Tseng_Labs_ET4000_Graphics_Controller_1990.pdf

[coromonadalix]

man a 33 year  datasheet      getting old here

[Alex_Baker]

I did end up installing some jumpers and testing different combination, none of which had any effect on the corruption.

I may just need to cut my losses on this thing, which is annoying because it was cheap for an ET4000, but not that cheap for an ISA VGA card.

[Alex_Baker]

Well now I feel stupid, the Tseng card works now, let me explain.

I decided I would search through the bios for anything that could help me. I found settings for ROM shadowing and some various other video related things, no differences. But I found a setting called "Hidden Refresh" under advanced chipset settings, as it turns out disabling whatever that is solves all my woes. If anybody can explain what hidden means I am all ears, but for now I am just going to take what I can get.

Should I have looked through the bios before? probably.

[nctnico]

It could be a soldering issue on the Tseng labs chip itself.

[coromonadalix]

from vogons ??

never heard of that one ?

Hidden refresh is a method to do a refresh cycle as part of normal access cycle to a DRAM chip rather than needing a dedicated refresh cycle which will be slower, it helps to increase memory bandwidth. All 72pin SIMMs support hidden refresh and most 30pin SIMMs should too, at least 1MB and bigger ones.
Slow refresh is extending the time period between refresh operations to reduce bandwidth needed on refreshing the memory to increase performance. Data corruption can happen if the memory cannot handle it, you will have to experimentally verify that things are stable.

[rsjsouza]

I have been silently following this thread and I was going to suggest to wash your board (residue and other issues can sometimes affect funcrionality), but thanks for sharing the solution. I have seen many BIOS options over the years but I don't remember that one.

Enjoy your "new" board

[mfro]

I guess this doesn't help much with your problem, but it appears to me the card is *not* an ET4000 W32i but a plain ET4000 (as it has the ET4000AX chip).

[HwAoRrDk]

I guess this doesn't help much with your problem, but it appears to me the card is *not* an ET4000 W32i but a plain ET4000 (as it has the ET4000AX chip).

Oh yeah, that's true. I didn't notice that. A W32i will have a chip marked "ET4000/W32I".

Is OP sure they're not just using the wrong drivers?

[Alex_Baker]

I guess this doesn't help much with your problem, but it appears to me the card is *not* an ET4000 W32i but a plain ET4000 (as it has the ET4000AX chip).

Oh yeah, that's true. I didn't notice that. A W32i will have a chip marked "ET4000/W32I".

Is OP sure they're not just using the wrong drivers?

I was starting to wonder about that, it must be a problem with how the PC benchmark program I was using reports it, which is a W32i, but I don't know how it would actually tell.

[coromonadalix]

had doubts with the VG-5500 markings ??  even the fcc id markings ??

[Alex_Baker]

had doubts with the VG-5500 markings ??  even the fcc id markings ??

As big as compuadd was at one point (according to Wikipedia) I got no results looking up those markings, so all I had to go off of was the incorrect reporting of the benchmark software.