Re: The quest for best potentiometer for PC speaker volume knob turned out not 100% perfect :(

Posted on 2022-01-29, 09:03

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

10K sounded too high to me for audio volume, most stuff I've seen it would be 1-5K... I wonder if it's not original even, so the part you found in there never "worked perfect" but was a "I'll just stick this in because it's what I've got kicking around". I think you are right there - looking at the …

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The quest for best potentiometer for PC speaker volume knob turned out not 100% perfect :(

Posted on 2022-01-28, 17:01

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Heya, recently I learned something new about potentiometers that I did not know before, so thought to write a story about my experiences, and where my learning ended up with. On a 8088 Turbo XT clone that I am restoring, there was an audio volume knob set up at the ISA slots on the back. Some 30 …

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Re: An adapter to connect Commodore joysticks to a PC DB15 connector?

Posted on 2022-01-19, 20:45

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks, those look like great solutions!

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An adapter to connect Commodore joysticks to a PC DB15 connector?

Posted on 2022-01-19, 13:04

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi all, does anyone know if there would exist an adapter that would allow connecting a Commodore 64/Amiga Joystick, e.g. a Tac-2 ( https://en.wikipedia.org/wiki/TAC-2 ) to a PC's DB15 port? I find that a lot of the old games only need digital X/Y axes, and I am struggling to find a decent joystick …

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Re: I hate the old white plastic motherboard standoffs - any replacement?

Posted on 2022-01-15, 21:55

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks, ordered a set, the sizes do indeed seem to match. Hopefully that'll be an easy replacement for the mobo setup without surprises.

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I hate the old white plastic motherboard standoffs - any replacement?

Posted on 2022-01-15, 09:12

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi all, I am restoring an old 8088 Turbo XT clone PC. One of the things that is bugging me is the way that the motherboard is fastened on the case. The motherboard has nine holes to connect it to the case, and the case has matching nine holes in it. In six of them, I find these annoying plastic …

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Re: Are there games that run playable on a XT 8088 PC can take advantage of either EMS or UMB?

Posted on 2022-01-03, 17:55

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Depends on how you define playable but yes there are a couple games more 286 aligned that will physically run on an XT that are more playable on an XT with EMS present, sometimes you get a couple extra graphical features when you have ems. If you have a Turbo 8086 XT (or NEC V20/30) there are …

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Are there games that run playable on a XT 8088 PC can take advantage of either EMS or UMB?

Posted on 2022-01-03, 14:19

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Heya, 1) it is possible to install a dedicated EMS card on an XT and 286 class of PCs, e.g. https://www.lo-tech.co.uk/wiki/Lo-tech_2MB_EMS_Board There's a list of games that can leverage EMS memory to their benefit: https://www.vogonswiki.com/index.php/List_of_programs_that_require_EMS Looking at …

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Re: What are the better 5.25" 1.2MB floppy drives around?

Posted on 2022-01-02, 09:02

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I found that my Epson SD-700 would not pass the King's Quest 1 copy protection check (the "Formaster Copylock" sector), but my Y-E DATA YD-380B rev1736B00W 1.2MB drive and Fujitsu M2551Ao8 360KB drives would. That could be due to a head misalignment or similar (though the Epson would otherwise …

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Re: 8088 CPUs gaining sentience in 2022

Posted on 2022-01-01, 12:54

by

by clb

in Milliways

in Milliways

Haha, awesome replies :) Now I realize there are other castling bugs in that game as well. It is possible to king side castle as the first starting move as white, when none of your pieces have even cleared out of the way. :> The IBM Chess88 from a few years later is actually an amazing …

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8088 CPUs gaining sentience in 2022

Posted on 2021-12-31, 21:20

by

by clb

in Milliways

in Milliways

Scouring old PC / DOS games, I find that one of the oldest games is Chess written in 1980, released in 1981 on IBM PC by International PC Owners. Here's a YouTube video (not mine) for illustration: https://www.youtube.com/watch?v=nX9SxYhYgpc I think my chess skills are around 900-1200 ELO. Played …

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Re: Stuck on disk change in 5.25" King's Quest 1 1984 version, "That is the wrong disk"

Posted on 2021-12-31, 20:56

by

by clb

in Marvin \ Software

in Marvin \ Software

This was tested on a 486 PC. I'll give it a try on a 8088 to see if that'll fix it, though I need to get a new floppy controller for that system in order to play it there.

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Re: Stuck on disk change in 5.25" King's Quest 1 1984 version, "That is the wrong disk"

Posted on 2021-12-30, 21:18

by

by clb

in Marvin \ Software

in Marvin \ Software

The usual test with computers floppy drives is do a dir on a floppy disk, swap for different floppy disk and do a dir again. If correct, the listing will be different. If not, and do a control+c and redo dir and listing changes, then you have a change disk detect switch, cable with a pin disk …

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Stuck on disk change in 5.25" King's Quest 1 1984 version, "That is the wrong disk"

Posted on 2021-12-30, 16:41

by

by clb

in Marvin \ Software

in Marvin \ Software

I am playing one of the earliest DOS versions of King's Quest 1 from 5.25" floppies. I used KryoFlux to write the floppies from archive.org title "Kings Quest I[ PC 360k]" uploaded by user Gypsy Dave. This scheme authors floppies that successfully carry the needed copy protection track, and the game …

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Re: Manual/jumper settings for a 16-bit ISA IO controller UMC UM82C862F for floppy drives?

Posted on 2021-12-28, 23:13

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for the suggestion! That is some sharp thinking - indeed it looks like the controller was missing jumpers. I populated the remaining row with jumpers, and just as if by magic, all my floppy drives are now working with the device.

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Manual/jumper settings for a 16-bit ISA IO controller UMC UM82C862F for floppy drives?

Posted on 2021-12-27, 19:01

by

by clb

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi all, I have this old multi-IO controller that has a floppy disk connector on it. Trying to use this with a 486 PC to connect a 5.25" floppy drive or a 3.5" floppy drive, but whichever I try (tried 4x 5.25" drives and 2x 3.5" drives, of which the 3.5" drives at least are tested on other systems to …

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Re: Which LCD, VGA->HDMI converter, or a CRT solution? Facing an odd non-standard 87Hz DOS machine

Posted on 2021-07-25, 16:29

by

by clb

in Marvin \ Video

in Marvin \ Video

On archive.org I found a publication on Nokia's own "Softari" magazine issue 2/1989, which announces the new MikroMikko 4 PC lineup that is in question here. https://ia803103.us.archive.org/17/items/Softari_ohjelmisto_lehti/Softari%202-1989_text.pdf That issue contains a piece about display eye …

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Re: Which LCD, VGA->HDMI converter, or a CRT solution? Facing an odd non-standard 87Hz DOS machine

Posted on 2021-07-25, 15:24

by

by clb

in Marvin \ Video

in Marvin \ Video

There are some jumpers, but unfortunatly no notes on them. I have not dared to adjust them in the chance of doing damage to the board - in the absence of documentation for the motherboard.

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Re: Which LCD, VGA->HDMI converter, or a CRT solution? Facing an odd non-standard 87Hz DOS machine

Posted on 2021-07-25, 13:07

by

by clb

in Marvin \ Video

in Marvin \ Video

AFAIU, the Paradise VGA card you have behaves in a way the is not representative of a normally working VGA card under DOS . I agree that this is not a standard VGA behavior. Respectfully, I believe it would be more productive to try to address/fix the issue with your Paradise card than to try to …

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Re: Which LCD, VGA->HDMI converter, or a CRT solution? Facing an odd non-standard 87Hz DOS machine

Posted on 2021-07-25, 06:45

by

by clb

in Marvin \ Video

in Marvin \ Video

I measure no resistance between pins 10 and 12, so I connected them with a 10kOhm resistor in between. Doing that, and booting with nothing connected to the VGA port except the pins 10-12 via the resistor, the system boots with a yet third refresh rate: hsync=31.46kHz, vsync=58.92hz, ossc detected …

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