Re: CGA/EGA capture with 6€ logic analyser

Posted on 2020-06-25, 15:39

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

no it doesn't more lines = higher pixel clock since they all conform to 60Hz vertical Exactly. As long as we don't go super EGA, we have to deal with two dot clocks: 200-line modes run CGA compatible at 14.318 MHz 350-line modes run at 16.257 MHz (same pixel clock as MDA) As EGA has only 640 and …

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Re: Bought these (retro) hardware today

Posted on 2020-06-24, 05:58

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Concord-Eracom also made hardware cryptographic modules for financial institutions (banks). The first card with the obscured module on the left and the component "do not head above 212F during assembly" actually seems to be a cryptographic module. The key is kept inside that opaque module in static …

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Re: Does this look like an attempted repair?

Posted on 2020-06-24, 05:46

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This doesn't look like an attempted repair, but to scratching damage. I had something similar happen to my Adaptec 1542B, when I put it into the same antistatic bag as a more modern graphics card. I placed those cards solder-side to solder-side, which usually turns out well, but in this case, the …

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Re: Error: Invalid \ No keyboard code received ?

Posted on 2020-06-23, 01:18

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes you need a XT keyboard or one of the rare XT/AT (Like IBM model M, Hewitt Rand SK-2000R, Nan Tan 6252EA, etc) that either auto switch AT and XT or have a switch to select XT or AT. I know of no cheap ones and do not know how the adapters would work since the KB signals and KB controller for XT …

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Re: 486DX2-66 project update

Posted on 2020-06-23, 01:09

by

by mkarcher

in Marvin \ System Specs

in Marvin \ System Specs

Thank you for the ideas! I know that serial mice will work on this system, but from what I've seen, PS/2 mice connected to a serial adapter will not work. The simple small PS/2-to-serial plug adapters do not convert any PS/2 mouse into a serial mouse. For these adapters to work, you need a special …

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Re: Are there any soundfonts (sf2, GM) for some old soundchips?

Posted on 2020-06-23, 01:00

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

I am not sure I understand your question. If it is about getting a Creative Labs sound card with a driver including sound fonts, you could get a Soundblaster Audigy 2 NX. The driver (at least the package for old versions of windows) comes with the standard sound fonts that were also supplied with …

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Re: 486DX2-66 project update

Posted on 2020-06-22, 23:43

by

by mkarcher

in Marvin \ System Specs

in Marvin \ System Specs

Yeah, this is what i meant, i apologize. I think a lot of older serial-mouse only boards might be confused by applying ground on one of the RS232 lines if the board doesn't have the necessary filtering, because I wonder if the occasional crashes are coming from the PC reading noise on the line as …

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Re: Pentium MMX 450MHz

Posted on 2020-06-22, 23:27

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just for the record, screen shots of K6-2 and K6-3 running on the same mainboard with the same settings. write performance in MB/s K6-2 K6-3 Tillamook L1 MMX 2425.74 2489.26 169.60 L2 MMX 245.39 1248.84 168.95 L3 MMX 245.34 Mem MMX 110.00 144.89 169.21 BTW why write performance is such BS on many …

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Re: Are there any soundfonts (sf2, GM) for some old soundchips?

Posted on 2020-06-22, 22:55

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Well, the music synthesizer on the SB!Live is nothing but a hardware-accellerated SF2 playback engine. You can get the same music synthesis one gets from the SB!Live (save for the reverb/chorus, which is not Soundfont-based, but added by a separate effects section) by using the SoundFonts shipped …

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Re: 486DX2-66 project update

Posted on 2020-06-22, 22:43

by

by mkarcher

in Marvin \ System Specs

in Marvin \ System Specs

I wonder maybe your mouse port needs diodes to prevent backfeed? (This might not be the issue at all.) I love that case / setup. Both the clock and the data line on the PS/2 mouse port are bidirectional. I don't see how to put diodes into these lines without disturbing the communication. I diode on …

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Re: Success: Adding a PS/2 mouse port to the Shuttle HOT433 (using a dedicated keyboard controller chip)

Posted on 2020-06-22, 22:18

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm wondering, do you have any documentation about these chipsets ? You mention strap pins etc. No, I do not have any documentation. There is a thread here on VOGONs requesting documentation for UMC chipsets in https://www.vogons.org/viewtopic.php?f=46&t=68829 . This thread contains a schematic for …

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Re: ES688: FM distorted on Line-Out, smooth on Speaker Out.. What gives?

Posted on 2020-06-22, 20:17

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Interestingly I noticed that FM music is extremely distorted on Line-Out but otherwise perfectly smooth on Speaker out. What could be the cause? Is the distortion due to hooking it up straight to el cheapo headphones or TV audio in? Line-out is designed to deliver some voltage to an amplifier, but …

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Re: identify 486 motherboard

Posted on 2020-06-22, 16:59

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sorry to scare you. I can't remember having seen the "keyboard locked" message due to a missing keyboard, but if it works fine now, good for you. I will keep that in mind before scaring other people. This actually looks fine, but oviously the BIOS is a bit dated and does not know the brand name of …

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Re: identify 486 motherboard

Posted on 2020-06-22, 15:32

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Floppy disk(s) fail is OK if no floppy controller or floppy drive is connected. CMOS checksum error is normal if the CMOS battery is flat. Keyboard error or no keyboard present is expected if indeed no keyboard is connected. "Keyboard is locked out" is not expected when you test a board, and most …

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Re: New sound card project: AWE64 Legacy

Posted on 2020-06-21, 21:04

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Going from memory here - but I could swear there was an issue with one of the star trek adventure games. Either judgement rites or 25th, I can't remember exactly what it was but I think it was related to getting stereo opl3 maybe? Stereo OPL3 on a soundblaster pro 2 should work perfectly at ports …

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Re: Success: Adding a PS/2 mouse port to the Shuttle HOT433 (using a dedicated keyboard controller chip)

Posted on 2020-06-21, 17:25

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

By the way, I recently ordered some UV-erasable 8042 chips (i.e. 8742 chips) that can be used as keyboard controllers. Does anyone know a (preferably legal) source for a PS/2 compatible firmware image for them? I just assumed the open-source community already had developed suitable firmware, but my …

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Re: Newly made ISA CL-GD5434

Posted on 2020-06-21, 17:10

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by mkarcher

in Marvin \ Video

in Marvin \ Video

Even if you could build a card that would fully use the 16.67 MB/sec. possible with 16-bit ISA, do the maths on how many frames you can get thru. And I've yet to see an ISA graphics card being able to push more than 7 MB/sec. over the bus. Actually, the fastest you can put over ISA (not overclocked …

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Success: Adding a PS/2 mouse port to the Shuttle HOT433 (using a dedicated keyboard controller chip)

Posted on 2020-06-21, 16:52

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I successfully added PS/2 support to Disruptor's Shuttle HOT433 (rev 1, 2 or 3) mainboard (using an external KBC). This post is a detailed explanation on what needs to be modified on the board to switch it to external keyboard controller support, and suggests a BIOS image that can be used as base. …

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Re: All the truth about FM in ALS100 Plus+ cards (includes facts, tech info and tests)

Posted on 2020-06-20, 09:03

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Great analysis! [*] The ALS100 Plus+ chips DO NOT HAVE an internal FM implementation. Avance Logic CHEATED on the documentation. Okay, now, as shown in ALS100+/ALS200 documentation, this chip has internal FM emulation (nope, cheaters!!). To enable it, without external OPL3 chip mounted, ALS100+ pin …

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Re: 386 Systems and Memory Instability With 4mb SIMMs? (Errors)

Posted on 2020-06-20, 08:22

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Slow refresh cannot be disabled, only set to 15, 30, 60, and 120. One of these all-to-often confusing setup option names. "15" is the settings you would call "disabled". The setting actually seems to mean "refresh interval in microseconds". Industry standard is 15.6 microseconds per row, which …

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