Re: AWE32 (CT2760) Diagram to help Recap?

Posted on 2024-01-20, 13:43

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by mkarcher

in Marvin \ Sound

in Marvin \ Sound

I'am in too ! My CT2760 start to have it's left channel being too quiet. I have another a SB16 (CT2230) who has the same issue, but here left channel is just inaudible. Could this be due to stereo amplifier TEA2025b or caps or both ? As far as I understand the SB16 architecture, the TEA2025B power …

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Re: Peaktron XT multi function card

Posted on 2024-01-20, 13:38

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I looked around to see how the RTC was accessed, but nothing in config.sys or autoexec.bat seems to do something with time at all. There is a cmosclk.sys file in the dos directory that is 878 bytes in size. So there likely is a DEVICE=C:\DOS\CMOSCLK.SYS line in CONFIG.SYS that loads this driver, …

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Re: Peaktron XT multi function card

Posted on 2024-01-19, 17:23

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

"1701" is the error message by the HDD controller BIOS that the hard drive is not properly responding to controller requests. You should make sure that The drive select jumper on your ST225 is set to "first drive" The (wide) control cable between the hard drive controller and the ST225 is properly …

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Re: 386 Cache / SRAM help/clarification needed

Posted on 2024-01-19, 17:12

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What is the 11th chip's purpose? It's required for 64k but not 256k. I'd like to document the chip but am unsure if it's a "dirty bit" chip, or a third "tag" chip or what? It seems to confirm this suspicion: the cyan chip contains two extra address tag bits that are only used in the 64KB cache …

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Re: EGA together with mode13h

Posted on 2024-01-16, 17:45

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So we can load characters of height 8, 14 and 16. Anything else? The BIOS contains built-in fonts of height 8, 14 and 16. The BIOS also allows to load custom fonts of any height between 1 and 32. I would refrain from heights one and two, because at 400 scanlines, this would produce 400 or 200 rows, …

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Re: EGA together with mode13h

Posted on 2024-01-16, 13:54

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Is there a more permanent method to set 80x28? (like mkarchers link did for 80x43) I'm afraid there is not. The Borland IDEs insist on re-initializing the video mode. The recognize the *43 / *50 modes and also re-configure the font to 8x8 after setting mode 3, but this is not a generic solution to …

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Re: EGA together with mode13h

Posted on 2024-01-16, 13:52

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The number of lines of text and the resolution determine the size of font. Changing the font won't affect the number of lines of text. That's only partially true. When you use INT 10h, AH=11h, you can optionally enable "text mode adjustment". If enabled, the BIOS will reprogram the character height …

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Re: EGA together with mode13h

Posted on 2024-01-15, 20:07

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The VGA card is able to produce the 43 line mode if you configure the text mode to use 350 lines instead of 400 lines. There is a BIOS call to downgrade text modes to 350 lines or 200 lines you can invoke before initializing mode 3. I'm unsure whether that call only works for the next mode set, or …

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Re: Can anyone identify this video chip?

Posted on 2024-01-15, 20:01

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by mkarcher

in Marvin \ Video

in Marvin \ Video

That's a custom ASIC ordered by Compaq and produced by Motorola. The Compaq part number of that custom chip is 121927-002. It happens that the same chip is mounted on the Compaq Advanced VGA . The VESA driver for the card can be found at https://archive.org/details/CPQVESA . Compaq SoftPAQ SP2225 …

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Re: Testing SRAM cache chips

Posted on 2024-01-14, 23:15

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Obviously the problem is that my Arduino Mega is a 16 MHz device so it doesn't have enough timer precision and instruction latency to deal with nanosecond time intervals on digital outputs needed for testing -10 or -15 ns chips at the maximum rate. While you can't do that, the Arduino is good …

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Re: 16-bit ISA EGA card?

Posted on 2024-01-14, 21:01

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by mkarcher

in Marvin \ Video

in Marvin \ Video

I've meant to say that if history was different, and if what had finally become "VGA", had rather been ended up more like an evolved form of EGA.. Some sort of Super EGA, so to say: No analogue output, but full 64 colour ouput for an EGA/TTL monitor. With a dedicated 64 colour "on screen" video …

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Re: 16-bit ISA EGA card?

Posted on 2024-01-14, 19:20

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by mkarcher

in Marvin \ Video

in Marvin \ Video

Because, in the mid 80s, the rare IBM PGC did offer 640x480 @256c already. W/ VGA timings and similarly specs (31,5 KHz + 60Hz, but combined HC Sync). Nitpick: It's 30.5kHz on the PGA, not 31.5kHz like on VGA. The PGA monitor needs some trimming before it synchronizes the VGA scan rate, even if you …

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Re: 16-bit ISA EGA card?

Posted on 2024-01-14, 19:07

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by mkarcher

in Marvin \ Video

in Marvin \ Video

Come to think of it, maybe there was a Super EGA card with 64 simultaneous colors? I'm not aware of one, but we all know that absence of evidence is not evidence of absence. There would be one big problem with such a card, though: difficult to convince software vendors to support such an oddball. …

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Re: 16-bit ISA EGA card?

Posted on 2024-01-14, 19:05

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by mkarcher

in Marvin \ Video

in Marvin \ Video

There also was an analogue 9-pin connector on early VGA cards, I vaguely remember. There is analog video on 9-pin connectors. Different pinouts were used, but one of them turned into a de-factor standard. It's the one used by the IBM PGA ("professional graphics adapter", an early "high definition" …

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Re: 16-bit ISA EGA card?

Posted on 2024-01-14, 09:37

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by mkarcher

in Marvin \ Video

in Marvin \ Video

excellent informations! thx! I am thinking about changing my ET4000 against something more period correct in my A2000/A2286 BB. I was thinking about an EGA card... were there EGA cards that offer more resolutions and colors like the standard EGA cards did? I am still searching for an overview of …

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Re: UMC UM85C418F RAM - 2MB possible + desirable?

Posted on 2024-01-13, 19:05

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by mkarcher

in Marvin \ Video

in Marvin \ Video

dionb wrote on 2020-03-04, 23:28: Can't figure out what the UM9502 is doing, That's the clock synthesizer for the VGA pixel clocks. That's why it is located next to the 14.318 MHz reference crystal.

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Re: Orchid Technology 640x480x256

Posted on 2024-01-13, 18:42

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by mkarcher

in Marvin \ Video

in Marvin \ Video

I suspect the image I'm looking for came with a graphics card, though - the "640x480x256" suggests some graphics demo, or diagnostics? Many SVGA cards came with driver disks that included drivers for common DOS applications, and some refresh rate setup and mode test tool. It sounds very likely that …

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Re: Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers

Posted on 2024-01-13, 18:37

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

maxtherabbit wrote on 2024-01-13, 14:56: Both of my cards shipped with 1.1 and work fine with your BIOS Thanks for confirming!

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Re: Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers

Posted on 2024-01-13, 18:36

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

But can I use a compaq ECU on this board? Likely not without patching it. It is perfectly correct that many Compaq OVL files only work with the Compaq ECU, but for some reason, but during startup of the Compaq ECU, it performs some low-level port I/O to trigger some Compaq specific functionality. …

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Re: Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers

Posted on 2024-01-13, 09:06

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by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

- With original BIOS (1.1), the BIOS message shows, but complains about invalid EISA config and doesn't even try to detect devices The board is configured using newest EISA .CFG/.OVL files. I'll try original BIOS with older .CFG/OVL to be sure, but.. This sounds like a software compatibility …

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