Re: AMD DX4 100MHz build

Posted on 2020-11-17, 01:51

by

by kdr

in Marvin \ System Specs

in Marvin \ System Specs

Cool, that's the exact same CD-ROM and interface card as what I found in a recent 486 purchase! When I bought the system I thought I was getting luck and it had a strange or exotic sound card, but nooooooo it was just the CD Audio output jacks on the Philips CD interface card. 😀

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Re: GIANT IBM vintage hard-drive

Posted on 2020-11-15, 21:10

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nice find! I'd suggest asking this same question over at the Vintage Computer Forum (http://www.vcfed.org/forum/forum.php) as well, since they tend to be interested in really ancient non-PC stuff like this.

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Re: How to slow down NEC V20?

Posted on 2020-11-15, 09:45

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

if it doesn't match, it does a hlt (interesting that it doesn't do any beeping). One of my XT clones (a Datamini 10Mhz turbo) has a Phoenix BIOS that is utterly silent. Doesn't beep on boot. Missing video card? No beeps! Bad keyboard? No beep. I actually thought the board was dead when I first …

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Re: Need some advice on CGA card repair

Posted on 2020-11-06, 01:53

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd recommend using a 10uF 25V tantalum cap as the replacement. It'll keep the card looking more authentic and will be better suited for smoothing out high-frequency switching noise than a generic electrolytic. It's not difficult to find a suitable (2-leg) tantalum.

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Re: List of Web Browsers For All Operating Systems

Posted on 2020-10-30, 00:18

by

by kdr

in Release Announcements

in Release Announcements

Has anyone else had trouble getting Retrozilla to work on Windows 95? I tried installing Retrozilla 2.2 on my Win95b (OSR2.0) machine but it doesn't start. It just displays the Retrozilla splash screen and then... the splash screen vanishes and nothing else happens. No debug output anywhere, and I …

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Re: Bought these (retro) hardware today

Posted on 2020-10-25, 20:21

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I thought I got myself an 8bit ISA serial card for 1Euro. But then I realized that its a female connector. Too few pins for VGA. Did I buy a CGA/Monochrome video card? Can I use it on a VGA monitor with a passive adapter? What is the text on the main chip? I can't quite make it out from the photo …

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Re: I recently found this hardware, AKA the Dumpster find thread.

Posted on 2020-10-25, 03:14

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My guess would be a non-CGA/EGA/VGA card for a high-resolution monitor used for Desktop Publishing or something like that. Most likely not CAD/CAM, as high-resolution CAD/CAM cards have their own processor to accelerate drawing - this card doesn't seem like a high-end accelerator. Not a bad guess. …

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Re: Best and most compact compiler to build Freedos Kernel etc.

Posted on 2020-10-24, 06:04

by

by kdr

in Milliways

in Milliways

I can't help but interpret your question as "what is the smallest compiler that has enough features to compile FreeDOS?" and surely Turbo C 2.01 is the winner on this metric: TCC.EXE is a mere 180,385 bytes. Add 21,717 bytes for TLINK.EXE and you've got a pretty compact toolchain! Good luck fitting …

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Re: An AdLib-Compatible Card (1986) Older than AdLib (1987)

Posted on 2020-10-22, 03:15

by

by kdr

in Marvin \ Sound

in Marvin \ Sound

So who first came up with the idea to put an OPL2 on an ISA card? Wikipedia says the YM3812 was created by Yamaha in 1985.

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Re: Unknown network card drivers for dos.

Posted on 2020-10-21, 04:53

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's a National Semiconductor DP83905 chip. The datasheet [1] says "Software compatible with Novell's NE2000/Plus industry standard", so I'd hazard a guess that it will work with a generic NE2000 packet driver. It's jumperless so there will be a utility to configure its I/O address, but you can …

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Re: Sigma Designs EGA cards - a deep dive

Posted on 2020-10-19, 08:28

by

by kdr

in Marvin \ Video

in Marvin \ Video

I hacked up the SPEGASYNC video BIOS so that it can load as a TSR and edited its video mode table to use CLKSEL=10 [feature connector] for the 200-line modes. (This BIOS doesn't try to program the CRF9 register at all, so it stays at its default value of 00h=double-scan disabled.) With a jumper …

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Re: CRT monitor screen looks like interlaced

Posted on 2020-10-19, 05:21

by

by kdr

in Marvin \ Video

in Marvin \ Video

It's normal/expected that modes like 720x400 (VGA text mode) and 640x480 will show scanlines on a large CRT that's been designed for higher resolutions. In order for modes like 1024x768 and 1280x1024 to be legible, the electron beam needs to be quite narrow, making 400-line and 480-line modes have …

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Re: Sigma Designs EGA cards - a deep dive

Posted on 2020-10-19, 03:00

by

by kdr

in Marvin \ Video

in Marvin \ Video

During loading of the EGA BIOS, port 3DA, bit 2 is probed (conditional jump at BANK1:0B01). If it is clear, some "boot time emulation" is activated by calling CE01, which waits for the boot sector of a drive to be loaded and then activate the whole emulation machinery. I suppose this is meant to be …

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Re: BIOS image collection - requests, discussion etc

Posted on 2020-10-17, 23:28

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Wait a second - the ERGO480 does not just have faster RAM, it also has a faster dot clock. The SPEGASYNC runs at 14.318/16.267MHz, and the ERGO480 runs at 28.5/32.0. So the memory access is way faster on the ERGO480, because the sequencer is clocked at approximately twice the speed. Did you already …

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Re: Sigma Designs EGA cards - a deep dive

Posted on 2020-10-17, 11:51

by

by kdr

in Marvin \ Video

in Marvin \ Video

How do you obtain that message? Do you have an MDA card installed alongside the ERGO480 showing that message? Did you get a monitor wired up that syncs at 31.2 (which confirms that my examination of the mode table was correct)? Did you dump the screen buffer to a floppy and read it on a different …

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Re: BIOS image collection - requests, discussion etc

Posted on 2020-10-17, 11:43

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Does your 10MHz XT support adding a wait state to ISA cycles at 10MHz? In this case, you might want to try that. On the other hand, if it just adds a default wait state and the card adds extra wait states using IOCHRDY already, it might not help. It does not. I'm not even sure if it does add any …

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Re: „Below the root” hangs on IBM Portable 5155

Posted on 2020-10-17, 11:19

by

by kdr

in Marvin \ Software

in Marvin \ Software

I was able to play Below the Root on my 5155 tonight: IMG_20201018_001005.jpg IMG_20201018_001044.jpg This has been quite a mystery, because several people reported that this game worked just fine on an IBM model 5160. Which we know uses the exact same motherboard and BIOS as the 5155 portable. And …

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Re: EGA Video cards - BIOS image collection

Posted on 2020-10-17, 09:53

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

#17 Manufacturer/Identifier: NEL ELECTRONICS / "ULTIMATE EGA+++" Chipset: "UDL" C3 (8737KK) BIOS-String: NEL INTERNATIONAL 1987 IBM EGA COMPATIBLE SMART BIOS 5.93 11/17/87 Status: working in XT systems at 4.77Mhz and 8Mhz, display corruption at 10Mhz Oscillators: 16.257Mhz and 27.648Mhz IIMG_ …

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Re: Sigma Designs EGA cards - a deep dive

Posted on 2020-10-17, 07:18

by

by kdr

in Marvin \ Video

in Marvin \ Video

Okay, time for a quick update! The replacement RAM (TMS4464-10NL) arrived today, so I removed the bad RAM chip from the ERGO480 and soldered in an 18-pin socket in its place. After installing a new RAM chip in the socket, the card is finally able to POST without error. With the switches set to SW1 …

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Re: Bought these (retro) hardware today

Posted on 2020-10-17, 05:59

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

it was actually a SoundBlaster Vibra 16XV model CT4170 ISA sound card I recently got two of the Vibra 16XV cards (they were installed in a pair of old Socket 7 machines that I bought). No issues at all using them for DOS games because the PNP BIOS had set them up with 'reasonable' IRQ and DMA …

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