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386 Video Boot Issue

B

bigblock

Member
Joined
Nov 14, 2013
Messages
24
Location
Little Britain, Ontario, Canada
I'm trying to complete a 386 build and am having a heck of time trying to get the system to boot correctly in colour.

Half the time you boot from cold with a Trident ISA 1mb 8900 card, the trident bios logo/msg comes up in colour and then the system is good to go. But if reboot or are on a unlucky chance that from cold boot that the logo comes up in black and white, then everything stays in black and white. Bios, dos editor, windows. Everything in black and white.

I have tried another Trident video card with the same mixed bag results.

Also bought a speedstar 24x video card to try and get rid of this problem. It always shows up in colour when it boots, but after a few reboots you get 8 fast beeps and no matter what you do (change the wait state, irq or go from 16 to 8 bit bios) you cant get out of that 8 beep error code until I switch back to a trident card.

I've disabled video bios being cachable in the bios. Fooled with the video rom being cachable, disabled it all. Still can't figure this one out.


Mobo is a 386 Dx40, 256kb cache, IIT mathco@40mhz. 32mb ram and a 1992 Ami bos w/ opti495 chipset. It's a really good board.

I have another 386 board that I swapped off the ram and video cards to and I get the same colour / black and white results upon booting.

Have also tried just booting with the video card alone and nothing else plugged in - STILL same thing.

Any ideas?
 
Old VGA cards often test the connector to determine if a display is colour or monochrome, when using a newer VGA monitor it often gets confused and results vary.
I only have a couple of Trident cards which do this - so I make sure to use these with old CRTs - otherwise I try and use a different card that doesn't do it.

There is probably a proper solution, but I just avoid it.
 
Also try cleaning the ISA card edge connector. Although this is mostly a problem with VLB cards due to the extreme amount of contact area they have, it can also happpen to ISA cards -- a flakey connection to the motherboard causes it to work perfectly fine one time, and then bomb with the "no video" POST beep error on the next boot.
 
bigblock:

I'm presently working on my 386 build. I've had 3 video cards in my machine and have never experienced your particular problem. Presently, I too am using a Diamond Speedstar w/1 MB memory. I'm thinking you need to check and make sure that your board is seated all the way. When you snap the board in its slot, check to see that it's firmly in place after you screw down the bracket. Good luck.
 
When it boots to black and white try

MODE CO80

see if that kicks it back into color. If so, add that to the autoexec.bat
 
I never thought about the cable to the monitor causing the issue. I will try another monitor to see if that improves. But odd thing is that the black and white / colour issue only happens with the trident cards. The works flawlessly or 8 beeps upon boot happen with the speedstar.

I have tried each card in all ISA slots. Cards are clean and so is the board. But it wouldn't hurt to spray contact cleaner in the ISA slots to be sure?
 
I once had this happen on a monitor with a bad VGA cable. One of the colour signals had a loose connection and sometimes while you were working the screen would turn yellow, and you'd have to wiggle the cable to get proper colour back. If you started the system with only two of the three colour signals connected the videocard would start in black and white mode.
 
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