Are you using the same monitor with both machines?

Odd. I have this exact card, and it works fine in my 286.

konc wrote on 2025-09-18, 14:24:

Are you using the same monitor with both machines?

Yup, same monitor. I also happen to own two exact same cards and the problem occurs on both of them. Must be something with the 286 board (Octek Fox M 286) or the jumpers on the card. 😒

Strange thing is that the 286 is not posting with the WD card installed. No RAM check beeps, No error Codes, nothing.

No luck id'ing, is the 286 a fast one running the ISA at higher than normal speed
Ah https://theretroweb.com/motherboards/s/octek-fox-m-286 JP3 needed to be on for colour display, also maybe try in deturbo and then see if BIOS has control of ISA speed

I'll try this and report back, thanks.

When I start the PC in deturbo it boots and shows a picture! So it is ISA speed related? Any idea how to get this to work without a deturbo start?

When I start the PC with deturbo and reclock it to 16MHz when it booted up, any load on the GPU just crashes the PC. 😒

Is there an ISA divider in BIOS, needs to be /2 if it's referencing CLK, or /4 if it's referencing CLK2 - Looking at the manual for the II model, it seems there is a Fast I/O bus speed setting - this should be disabled, if this model soes it the same way,
Ah, one other thing, looking at the 90c30, JP2 could be a zero waitstate jumper, try taking it off, it might be able to handle full clock speed if it waitstates, can't find the model diagram, but a jumper on its own ansd set on it the most logical to be a 0WS

Unfortunately, the Fox M-286 doesn’t have an ISA clock divider. Adding wait states on the graphics card didn’t help either.
I’ve since found out that Western Digital VGA cards are particularly sensitive to higher ISA bus speeds.
The reason my Trident TVGA8900D-R runs flawlessly is that it’s much less susceptible to this.

I think I’ll stick with the Trident for now, or maybe switch to a Cirrus Logic 5420/5422. 😒

Trident 8900D is a pretty good VGA if you have the full 1mb installed, there is no speed reason to switch it for a 5422/24 IMHO

uniQ wrote on Today, 07:21:

Unfortunately, the Fox M-286 doesn’t have an ISA clock divider. Adding wait states on the graphics card didn’t help either. I’ve […]
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Unfortunately, the Fox M-286 doesn’t have an ISA clock divider. Adding wait states on the graphics card didn’t help either.
I’ve since found out that Western Digital VGA cards are particularly sensitive to higher ISA bus speeds.
The reason my Trident TVGA8900D-R runs flawlessly is that it’s much less susceptible to this.

I think I’ll stick with the Trident for now, or maybe switch to a Cirrus Logic 5420/5422. 😒

8900D is one of the fastest Trident cards with 1Mb memory, so I don’t think you lose that much, although WD90C30-LR is great too. I have Octek PVGA1D paired with my Octek Jaguar mobo and 386DX-33 and it pairs very well for that kind of system. When I was building and had the system on bench, I used 8900C and the difference is huge. Not a surprising result, but with 8900D you should be fine and I think both are getting close to being limited by ISA bus.

Also, with 286 the differences between graphics cards are less significant than for faster 386s or 486s.

uniQ wrote on 2025-09-18, 15:53:

konc wrote on 2025-09-18, 14:24:

Are you using the same monitor with both machines?

Yup, same monitor. I also happen to own two exact same cards and the problem occurs on both of them. Must be something with the 286 board (Octek Fox M 286) or the jumpers on the card. 😒

Have you tried swapping/changing ISA slots?

Looking through the technical manual for the WD90C30/31, for this board, there's a different wiring setup for upper address lines for 286s.

"For systems that do not meet the hold time of address valid[...] This applies to most 286 systems."

Attached the page. The upper part is for 286s, the lower part is for 386s onward.

286 setup:
A[23-20] combined into one and set to A23.
A19 connects to A22
A18 connects fo A21
A17 connects to A20
ALE connected to VCC
MD8 pull down to GND

A lot of modification if you really want it to work.

I have this same card and I did document the jumpers if anyone still cares about that.

uniQ wrote on Today, 07:21:

Unfortunately, the Fox M-286 doesn’t have an ISA clock divider. Adding wait states on the graphics card didn’t help either.
I’ve since found out that Western Digital VGA cards are particularly sensitive to higher ISA bus speeds.

Interesting that above pictured WD90C30 doesn't seem to like ISA bus overclocking in a 286. I have a few different WD90C31 ISA cards that will all run just fine at 16.5MHz ISA speed in my most excellent DTK PKM-3331Y all ISA 486 motherboard. Re: 3 (+3 more) retro battle stations