VOGONS


First post, by matze79

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Hi,

i got this nice little XT Mainboard, but i can't figure out what type it is.

Anyone has Information on this one ?

i wanted to know howto switch the damn Turbo.
Its running on 4,77Mhz but can also run at 8Mhz.

Common key strokes strg + shift + + and so on don't work.

The two Pinheaders near RAM (Yellow cap) are PC-Speaker and Reset.

Thanks

Matthias

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https://www.retrokits.de - blog, retro projects, hdd clicker, diy soundcards etc
https://www.retroianer.de - german retro computer board

Reply 1 of 12, by matze79

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Still no success.

I have made a better Picture.

board (Large).JPG
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Anyone knows howto activate Turbo Mode ?

Thanks

Matthias

https://www.retrokits.de - blog, retro projects, hdd clicker, diy soundcards etc
https://www.retroianer.de - german retro computer board

Reply 2 of 12, by derSammler

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Common hot keys are probably not working because this one has an AMI BIOS. Turbo XT boards normally came with some obscure / hacked custom BIOSes. What make you think this is a Turbo XT after all? The fact that the CPU is rated for 8 MHz doesn't mean that the board can do anything else than 4.77 MHz. I don't see any signs for switchable speed on that board.

Reply 3 of 12, by alvaro84

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I think it "must" be a Turbo board because it's so small and highly integrated.

I also think I'd bite the bullet and try putting jumpers on the remaining unknown headers while running a realtime benchmark like Landmark 2.0. It worked for me so far, I didn't fry anything.

Shame on us, doomed from the start
May God have mercy on our dirty little hearts

Reply 6 of 12, by carlostex

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Try to use this BIOS instead:

http://www.phatcode.net/downloads.php?id=101

I believe this BIOS has shortcuts for Turbo ON/OFF.

Not to brag but the ROM expansion between F000h to FE00h was my idea. I pitched this idea to Plasma to allow users to use the ROM BASIC socket for expansion ROMS too. Usually BIOSes stop looking for expansion ROM before F000h or F200h, so that would negate using the ROM BASIC socket that starts at F600h. But you can still use the socket for ROM BASIC.

I would recommend to everyone using an XT to try this BIOS, Plasma has done a marvellous job with it.

Reply 7 of 12, by matze79

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Yeah but it only detects 512Kb on my Board, Turbo is enabled with it even 9,54Mhz.

I really need 640Kb 😀

https://www.retrokits.de - blog, retro projects, hdd clicker, diy soundcards etc
https://www.retroianer.de - german retro computer board

Reply 8 of 12, by alvaro84

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carlostex wrote:

Try to use this BIOS instead:
http://www.phatcode.net/downloads.php?id=101

101-key enhanced keyboard support

Does it mean that it programs the KB controller to communicate with AT keyboards? Or it just has something to do with the extra keys in the XT mode of a 101-key "XT/AT" keyboard?

Shame on us, doomed from the start
May God have mercy on our dirty little hearts

Reply 9 of 12, by Plasma

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matze79 wrote:

Yeah but it only detects 512Kb on my Board, Turbo is enabled with it even 9,54Mhz.

I really need 640Kb 😀

This is odd, because the memory size is determined by a pattern write/read test. You can "force" 640K by changing line 545 from "add bh, 4" to "mov bh, 0A0h". But be prepared for Bad Things (tm).

alvaro84 wrote:
carlostex wrote:

Try to use this BIOS instead:
http://www.phatcode.net/downloads.php?id=101

101-key enhanced keyboard support

Does it mean that it programs the KB controller to communicate with AT keyboards? Or it just has something to do with the extra keys in the XT mode of a 101-key "XT/AT" keyboard?

No, you still need an XT keyboard. You can just use the extra keys and combinations like shift + gray cursor keys now work.

Reply 10 of 12, by alvaro84

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Plasma wrote:

No, you still need an XT keyboard. You can just use the extra keys and combinations like shift + gray cursor keys now work.

Sad. It would be very nice to be able to use standard AT/PS2 kayboards for my XT board. The only XT keyboard I have is not in the best shape. One day I'll try to repair it, I guess.

(I've already alleviated the other bane of XTs by running into an 8-bit SCSI card. It was fun to put a PCI SCSI controller into my Sandyi3/Win7 main rig and just copy things on the XT's HDD. Of course I can't use older DOS version for more base RAM because the partition on it is far larger than 32MB. And I tested it with a 1GB HDD too... that was more than nice 😁 I can find oldschool SCSI HDDs much easier than working MFM ones and they have no problems when I change controllers. I know about XTIDE but I'm still not sure about it. Do old cards with ROMs need EPROMs or flash BIOS chips will do too? In that case it may be possible to hot swap a flash ROM into something like a Socket7 board and burn XTIDE with UniFlash.)

Shame on us, doomed from the start
May God have mercy on our dirty little hearts

Reply 12 of 12, by alvaro84

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Plasma wrote:

Have you seen the AT/XT keyboard converter designs? There are several floating around. Just need a PIC and a few passives.

Nope. I have to level up before I think about building one.

Shame on us, doomed from the start
May God have mercy on our dirty little hearts