ET4000 FDC or HDC Error on 386 DX40 \ VOGONS

ET4000 FDC or HDC Error on 386 DX40

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First post, by SteFam

Posted on 2026-01-30, 20:31

SteFam Offline

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Rank: Newbie
Posts: 10
Joined: 2024-08-24, 21:02

Hi,

I am facing a stange problem, I wanted to replace the VGA in my 386 DX 40 by an ET4000 (isa 16, 1MB).
When I install the ET 4000 the computer stops after the bios checks.
I played around with some different Controller cards, best option is that only the FDC is not working.
I checked this also on two different 386 DX 40 boards with the same result.
I even checked with two different ET4000 Cards the same problem.

My option on that is that there is an address conflict. Unfortunatly the controllers have no ability to change the adresses.
On the Graphic Card I don't see any option/jumper to switch adresses.

Anybody :
* have an idea how to find and solve that problem
* knows good programms for analyses (beside checkit and nssi)
* some general ideas ... it is really strange
* A controller that can use different addresses or works with ET4000

Thanks for your help in advance, if you need further information let me know, then I will enhance this post 😉
BR Stefan

By the way I have searched before I wrote this, but maybe you have better a better search string for me.
searched for differnet combinations of ET4000, Address, conflict,FDC , Problem, (80)386 ...

Reply 1 of 4, by BloodyCactus

Posted on 2026-01-30, 20:46

BloodyCactus Offline

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Location: Lexington VA

the ET4000 does not have any IO ports on the Floppy/HD IO range. all these cards used fixed addresses that dont overlap.

what was your original vga card?

--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--

Reply 2 of 4, by SteFam

Posted on 2026-01-30, 21:26

SteFam Offline

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Rank: Newbie
Posts: 10
Joined: 2024-08-24, 21:02

@BloodyCactus thats the same I thought, I don't understand this.
Original card was a
Cirrus Logic GD5424 1Mb
Whole system is a Escom Slim Line

Original Mainboard was
FIC 386-SC-HG Rev:A
(I had some trouble to install 16MB ram (adressline seems not to be connected or one of the bus tranceiver has a defect)

Currently I use a
VIA-4386-VC-HD

Checked also some Bios versions before I switched the boards, currently I have a 486 Bios on the FIC 386-SC-HG Rev:A.

I have still the opinion that it must be something differnent, but when I remove the original hdc pc boots, if I install a different than the orginal Winbond Multi IO Controller, I can at least boot but FDC is not working.

Reply 3 of 4, by BloodyCactus

Posted on 2026-01-31, 01:35

BloodyCactus Offline

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Rank: Oldbie
Posts: 1561
Joined: 2016-02-03, 13:34
Location: Lexington VA

only thing I can think off is, some cards output a vga irq, most do not. its not a common used irq (its like irq 2/9?) and sometimes thats reserved by ACPI.

--/\-[ Stu : Bloody Cactus :: [ https://bloodycactus.com :: http://kråketær.com ]-/\--

Reply 4 of 4, by SteFam

Posted on 2026-01-31, 16:38

SteFam Offline

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Rank: Newbie
Posts: 10
Joined: 2024-08-24, 21:02

Thanks for the hint, now I have something addtional to be checked. I will check and come back.
I tested the graphics cards in the meantime in an 486 (without the io card, board has IDE and Floppy on board) There both HDC and FDC worked with all of three ET4000's.

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