Ati Mach64 hates floppy drives - a truly weird problem!

[houseisland]

Hi. This is a truly weird problem.

The card:

MACH 64GX "Vesa Local Bus" card w. 2 Mb ram (soldered in)

Bios VLB MACH1164 113-27801-102


Controller Type: VLB AT188800GX Rev. 1


The system housing the card:

Asus 486SV2GX4 w. 256K L2 Cache, I486DX4 100, 48 Mb Ram.

Promise DC3040VL-2 VLB Multi IDE controller card - IRQ 14 - w. 2 HDDs - primary controller, 4 Mb cache, but disabled because of NT.

Gemlight UN-1078E ISA IDE Controller / I/O card - IDE IRQ 15 w. 1 CD Rom, secondary controller - UARTS disabled - LPT2 IRQ7 Base Line 278.

Boca I/O AT55 I/O card - UART 2 disabled - UART 1 Com 1 IRQ4 - LPT1 IRQ7 Base Line 378.

Kingston KNE20T 10BaseT NIC - IRQ3 I/O 300

SIC Resource, Super Sound Origin, 32W3D Sound Card, Opti 925/941 chipset w. Cirrus/Crystal
CODEC - in DOS originally IRQ5, I/O 530, DMA 0/1 - now IRQ 10 - MPU401 IRQ 2/9 I/O 330 - IDE interface disabled - card not installed in NT.

PS/2 Mouse IRQ 12

Problem:

The card passes all the diagonistics tests in the package posted by Ati, and it behaves well in mostDOS 6.22 and NT applications until they access a floppy drive whereupon the screen begins a slow, almost psychadelic, process of meltdown. The screen is immediately restored by launching any application which has its own video drivers. For example: DOS commands and DOS utilities (Norton Commander), which use generic dos drivers, cause the meltdown when accessing floppies; Word 6.0 DOS, which has its own VGA drivers, restores the screen and does not cause any meltdown when accessing floppies; and any NT application which accesses a floppy starts the meltdown, but this process is reversed by opening another NT window and maximizing it.

The card resides in the adjacent slot to a Promise DC4030VL-2 multi-IDE Cache / floppy controller. Is EMI a possibility? I have tried attaching the floppies to the secondary controller but they fail in boot.

The bios chip was a little loose on the Ati card, age and heat maybe, and I tried gently reseating it. This action, however, changed nothing, neither improving nor worsening the performance of the card.

Any idea?

[clauded]

hi always had all kind of funny problems qith ati mach 64 vlb,have seen not being able to boot and everything eles you can think of,my advise is replace it with something else,even if it is a pretty good card when or if you can get it to work
Clauded

[houseisland]

This is probably good advice, but try to find a high end VLB video card which has NT support. Opinions vary about the quality of Ati's drivers and cards, but no one can fault Ati for lack of support for legacy cards.

I have the floppies on the secondary IDE controller now (forgot to disable the floppies on the Promise card before), and I have moved the secondary IDE card as far away from the Mach64 as possible. However, the problem has not gone away, so it's probably not any kind of EMI and it's probably not the Promise card.

There is no problem when accessing floppies on another computer on the network - no surprise here - so it's got to be some kind of memory conflict, but the floppies are on IRQ6 and normally do not interfere with anything??????

The Mach64 is a gorgeous performer, as long I don't want to use the local floppies. I hope someone can help.

Please note that this posting is also under the video heading. I also accidentally put it under input drivers - missed this slot by 1.

[This message has been edited by houseisland (edited June 08, 1999).]

[Nick Wightkin]

well, i usually see floppies using dma channel 2....but video doesnt use dma..

however, there may be an i/o port conflict..
since all vga compatibles use ports 3C0h-3DFh..if NT is trying to use those ports to make changes to the registers on the floppy drive, then that will cause trouble...
see if that is the case...

and, it's always good to pull all devices and controllers out...

only have the video card, the floppy, and the HDs...

try to use just one controller card..yank the other one..
(it may be a pain...but it may just help you eliminate the problem

-Nick

[houseisland]

Hi.

Thanks for the advice. I have tried everything that you have suggested, but it is all to no avail.

Unable to find a suitable replacement for the Mach 64, I bought a used P200 Pro MB and with stuff from my spares boxes put together a system to take the place of the 486, which is now moth-balled.

When I have time, I will look at it again.

Thanks.

[houseisland]

Hi. Back again. I finally got time to strip down the 486. Every individual component in the system works fine without the Ati card. Any of my Cirrus-based video cards work in the system. Put the Ati card into the system and the problem returns. Yet the Ati card performs wonderfully well in another mother board, an old Seanix item with an AMD DX2 80. Go figure!!!!

But hey, both items, the Ati video card and the Seanix MB, were designed in Canada!!! Maybe there's some sort of cultural isolationism and zenophobia here?

[This message has been edited by houseisland (edited October 23, 1999).]