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VLB card problem

J

JDT

Veteran Member
Joined
Feb 17, 2007
Messages
564
Location
Cicero, NY
I have a SZ959 CPU (intel DX4-100 Overdrive, 5v, 33x3) and a SK051 (intel DX4-100, 3.3v, 33x3) and a DIGIS-486GL Motherboard. I have a 1MB VLB Mach32 VIdeo card & a VLB floppy/IDE/multi I/O card. Motherboard installed with 16MBs of RAM (8x2).

When set to 33x3 (running @ 100MHz) the IDE connection from the controller card does not work. If set to 25x3 (running @ 75MHz) everything works all happy. I have the Video card in the VLB slot furthest away from the keyboard port. I have the VLB controller card in the VLB slot closest to the keyboard port.

If I use a 16-bit floppy/IDE/multi I/O card while running @ 100MHz, everything works all happy once again..

My question is, why is this happening?! lol I want to use the VLB card.. its probably something stupid I'm overlooking so Im hoping a fresh set of eyes on the situation might point it out.

There is a VLBus speed setting >33MHz & <=33MHz.. it is currently set to <=33MHz (doesnt seem to post when changed.
I've also tried switching VLB slots, in almost all configurations wit the two cards.

For refferance I have the following.

http://www.jdthiele.com/personal/digis-486gl.doc
http://www.jdthiele.com/personal/digis-486gl.jpg

controller card has following identifications:
UN-1085/UN-1086
FCC ID: 102-W83759AA

Thanks in advance for any assistance.
 
Last edited:
VL Bus is notoriously picky .. nowhere near as robust as PCI. That's part of the reason why it did not last long.

I'd run it at 25Mhz, or get another card to experiment with.
 
I had pretty good success with the VLB bus but I never used more than a VLB video card. Other one was always empty. VLB is supposed to work up to 40 Mhz (the fine print).
 
JDT said:
I have a SZ959 CPU (intel DX4-100 Overdrive, 5v, 33x3) and a SK051 (intel DX4-100, 3.3v, 33x3) and a DIGIS-486GL Motherboard. I have a 1MB VLB Mach32 VIdeo card & a VLB floppy/IDE/multi I/O card. Motherboard installed with 16MBs of RAM (8x2).

When set to 33x3 (running @ 100MHz) the IDE connection from the controller card does not work. If set to 25x3 (running @ 75MHz) everything works all happy. I have the Video card in the VLB slot furthest away from the keyboard port. I have the VLB controller card in the VLB slot closest to the keyboard port.

If I use a 16-bit floppy/IDE/multi I/O card while running @ 100MHz, everything works all happy once again..

My question is, why is this happening?! lol I want to use the VLB card.. its probably something stupid I'm overlooking so Im hoping a fresh set of eyes on the situation might point it out.

There is a VLBus speed setting >33MHz & <=33MHz.. it is currently set to <=33MHz (doesnt seem to post when changed.
I've also tried switching VLB slots, in almost all configurations wit the two cards.

For reference I have the following.

http://www.jdthiele.com/personal/digis-486gl.doc
http://www.jdthiele.com/personal/digis-486gl.jpg

controller card has following identifications:
UN-1085/UN-1086
FCC ID: 102-W83759AA

Thanks in advance for any assistance.
Click to expand...

As said, VLB can get edgy when more than one adapter is used at or above 33MHz, or even a low-quality adapter at or above 40MHz. The jumper setting you are referring to is a VLB wait state. With you saying it doesn't post may show one of the VLB adapters wants the wait state.

Also make sure you don't have a serial port set to COM4 with the Mach32 also present. My take is the combo card is low-quality, and limits abilities when you try to run it at 33MHz (also be aware that motherboards will differ how the VLB slots are set up in regards to busmastering). The ATI card should be good quality and the "keeper".
 
I tried using a weird super combo card I had. a VLB video/IDE/Floppy/IO card. Everything worked great @ 100MHz. BUT... it has some POS video chipset on it with like 256k of vram.
 
JDT said:
I tried using a weird super combo card I had. a VLB video/IDE/Floppy/IO card. Everything worked great @ 100MHz. BUT... it has some POS video chipset on it with like 256k of vram.
Click to expand...

Western Digital made a few of those cards, I have a couple and here is one:

http://picasaweb.google.com/teozenios/VLBCards/photo#5067910033396683474

A few of my other VLB cards are on that site, bit I have many more that need to be organized.

I have a couple VLB SCSI cards that do not function at 40Mhz bus speed. There are jumpers on the motherboard for VLB Bus speed that need to be set correctly. I think all 3 of my VLB system use 2 VLB cards (one is video and the other is storage IDE or SCSI) and they all function just fine. VLB gets weird when you try 3 VLB cards at once, since they are all on the CPU bus things get slowed down with wait states and CPU to memory transfers get slow. You might also have problems with BUS mastering cards being in the wrong slot or having too many of them.
 
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