Re: Latest BIOS for the SOYO 4SA2 motherboard?

Posted on 2022-11-02, 06:46

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Forgot to thank you for all the info mkarcher! If you or anyone knows which jumpers control the cpu bus multiplier please let me know. A 486 DX4 processor only uses a single jumper for the bus multiplier. The most common pinout (Intel DX4, Cyrix DX4, Cyrix 5x86, AMD Enhanced DX4 (SV8B), AMD 5x86) …

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Re: Expanded memory managers and DOS

Posted on 2022-10-31, 14:39

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

Are there any other EMM drivers that I could use on the XT? EMM386.sys asks for a 386 processor, but is there some emm.sys that could work? EMM drivers need to be matched to the hardware that provides EMS. EMM386 uses the 8086 virtualization feature built in the 80386 processor to provide EMS. …

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Re: Olivetti M20 monitor

Posted on 2022-10-30, 08:35

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Horun wrote on 2022-10-30, 02:58: I am clueless but am wondering why the B/W signal hit a 50v peak but you picture shows a 100mV scale. You are looking at the "max PkPk voltage" (that has ever been encountered since resetting the stats), not the "current PkPk voltage", which is 552mV, and coarsely …

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Re: MIDIto r12 (Midi and FM redirection, Mixer locking, Sound Blaster fixes)

Posted on 2022-10-30, 08:31

by

by mkarcher

in Release Announcements

in Release Announcements

But no sound output. I'm sure it's not technically viable because MIDI=/=FM instructions. It's absolutely not technically viable by just redirecting data. FM instructions are on a lower level than MIDI instructions. Many MIDI synthesizers don't do FM synthesis (which is absolutely great for synth- …

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Re: Olivetti M20 monitor

Posted on 2022-10-29, 22:01

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

-all data lines (D0-D7) are floating, -refresh memory adress lines MA0-MA9 are fine ( regular high/low transitions), but MA10-MA13 are floaring, -raster adress lines from RA0 to RA3 are fine, but RA4 is floating, -both chip select and register select lines are floating. Please check your probing …

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Re: What kind of memory is this?

Posted on 2022-10-29, 18:15

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

For 1 and 3 it looks like the presence detect resistors are all empty. Most consumer mainboards do not care about presence detect. It's big brand hardware like HP or IBM that cares about PD, even more so in printers like HP LaserJet printers. Because consumer HW doesn't care about PD, also a lot of …

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Re: Looking for best Windows accelerator for 386sx

Posted on 2022-10-29, 08:40

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

2. can you confirm an old statement here that the 2d performance of win nt4 is much faster (x5 to x10) as win 95? Generally said: No. There might be specific artificial benchmarks that result in a 10x speedup for a specific graphics card, but that's likely because the NT4 driver is better than the …

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Re: Surprise scratches on the inner surface of floppy disks are ominous

Posted on 2022-10-29, 08:32

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Damage like this can be caused by debris sticking to heads of a floppy drive. Cleaning the heads can put the drive back into normal operating coditions. Also, the surface of that floppy might have gone bad and starts to be scratchable by the normal head contact when you insert the floppy into a …

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Re: Wildcard 88 Motherboard RAM test Error on MDA, CGA

Posted on 2022-10-29, 08:24

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So is the motherboard's basic design wrong? I trust Sergey to have designed that board correctly. I'm more inclined to think about a fault in your specific build of that board, like a broken trace or a bad solder joint. Specifically, I suggested that the issue might be rooted in the connection of …

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Re: What kind of memory is this?

Posted on 2022-10-29, 07:30

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Be careful with the first module. I can't find datasheets at the usual place for those chips. I don't see any brand manufacturer name. I have some modules with these properties, and they often turn out to be of low quality, i.e. the memory is unreliable. Before trusting them in a system, I highly …

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Re: Wildcard 88 Motherboard RAM test Error on MDA, CGA

Posted on 2022-10-28, 23:07

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's interesting that the error message shows "expected" and "actual" both being FFh. This means that probably the value did not read as 0FFh at first, but when the location got re-read, it had the correct value. Getting memory errors at those addresses doesn't make any sense. CGA and MDA cards are …

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Re: So many choices so little time - Hercules graphics card decision (cloned title :-))

Posted on 2022-10-27, 19:03

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

An MDA monitor can be used for EGA monochrome mode (640x350 mono) sometimes, I vaguely remember. Exactly. Mode 0Fh on the CGA card is specifically meant to be displayed on MDA monitors. This is in contrast to mode 10h (also 640x350, but 16 colors) which is designed to be displayed on the Enhanced …

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Re: Creative AWE64 CT4500 upgraded to 2MB of RAM

Posted on 2022-10-26, 19:12

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

The plastic on the simm slots is broken (I bought it very cheap because of that issue). Why is the CT3600 not designed to work with 2mb of ram? Is there a technical reason behind it? It can work perfectly with 512KB of RAM, 2MB of RAM, 8MB of RAM or 32MB of RAM (28 of them usable). But 2MB chips …

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Re: Any chance of finding this missing PAL chip?

Posted on 2022-10-26, 17:12

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Finding the dump is likely nearly impossible. If you want to start an andventure, and this kind of adventure is up to your taste, get the board, reverse engineer what the PAL is supposed to do and derive the required equations. Otherwise: skip it.

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Re: Creative AWE64 CT4500 upgraded to 2MB of RAM

Posted on 2022-10-26, 13:45

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

Is the memory mod possible on the Ct3600? (SB32 PnP). I have one with no memory on board, and it would be cool if memory could be added. Is there a reason you don't just insert a pair of SIMMs? The CT3600 uses a PCB that is able to take a 256k x 16 DRAM chip, but it is easier and possibly cheaper …

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Re: Olivetti M20 monitor

Posted on 2022-10-26, 00:22

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I do not have much experience with that, but maybe it's RAM related issue. In Olivetti M20 hardware manual I have found such Video logic diagram. The Video BW pin should always be driven either high or low by the "video control" circuit (assuming it's a TTL level signal, as in MDA). Even if the …

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Re: Possible to output 320x200 for EGA games? (re: doublescanned 640x400)

Posted on 2022-10-26, 00:12

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

For 320 pixels at 15.7kHz you would just need 6.3 megapixels per second. A standard VGA card doesn't provide that clock, so either VGATV needs to do some magic, or it will only work with 640-pixel modes. In 256 colour mode the VGA outputs a pixel every other clock, right? So that plus the standard …

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Re: Hard drive rattling noise is OK! Sometimes.

Posted on 2022-10-25, 18:17

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

DAVE86 wrote on 2022-10-25, 07:32: A solution found in modern 2.5" Western Digial drives. This might well be true. The 2.5" IBM drive shown in the OP was the first mainstream drive to park the arms in a way that causes rattling noise. That's why these drives have the note printed on them.

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Re: Possible to output 320x200 for EGA games? (re: doublescanned 640x400)

Posted on 2022-10-25, 18:13

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

OK - I'm trying to run VGATV on the "weeCee" (Volaris Z9s chipset) and it detects the chipset as Tseng Labs but it the OSSC reports the signal as 263p (31.54 kHz, 119.93H) (using NTSC command-line option). If I try to play a Sierra game (ie. PQ1 AGI), the OSSC can't sync. The OSSC LCD flashes …

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Re: Olivetti M20 monitor

Posted on 2022-10-25, 18:05

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Bernkastel7734 wrote on 2022-10-25, 17:43: I'm not sure if it's MDA compatible or not, but I am sure it is not what a healty video output should look like. What signal are you scoping?

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