Re: Unknown card
Posted on 2021-07-19, 12:22
Those chips are IDT 71256SA15Y - 32Kx8 with a speedy 15ns access time. So yeah, my guess is that it's a 256KB L2 cache module (plus a couple extra chips for the cache tags) for an 80486 motherboard.
Re: Need help identifying purpose of unknown ISA card
Posted on 2021-07-14, 01:21
It's a bit hard to tell from the photo (how does a 1.3MB JPEG end up like that?) but the chips tell the story of what this card does: Intel P8344 - SDLC communications controller HM6264 - 8Kx8 static RAM IDT7201 - 512x9 parallel FIFO DS96176 - RS485/RS422 differential transceiver The Intel 8344 is …
Re: All the exact differences in programming interface for EGA vs VGA?
Posted on 2021-06-30, 22:29
This whole design with the flip/flop is often explained as "IBM did it to save on I/O addresses", and this explanation admittedly makes zero sense if 3C1 is aliased to 3C0. I assume this explanation is just folklore and wrong, and the real reason is not to conserve I/O addresses, but because IBM …
Re: TVM MD-3N - EGA or CGA Monitor?
Posted on 2021-06-27, 00:19
[*]You can use an EGA card to drive a CGA monitor, but you will be limited to 200-line mode. Most EGA cards from that era did have jumpers or switches on the card to disable the 350-line mode to ensure compatibility with older CGA monitors and also to avoid damage to the card itself. [*]Most EGA …
Re: EGA aesthetics
Posted on 2021-06-27, 00:03
I'm another fan of the EGA aesthetic. Your graphics are reminiscent of the early Lucasarts style from Maniac Mansion and the university scenes from the first Indiana Jones. Vibrant colours (you could almost call it 'garish') but not much use of dithering. That would come later, in LOOM and Monkey …
Re: TVM MD-3N - EGA or CGA Monitor?
Posted on 2021-06-23, 00:11
I don't think we have strong support for the assumption that the monitor supports 18.4kHz. We have clear evidence that the monitor does not support MDA/Hercules mono cards , though: The OP mentions that pin 7 (secondare blue on EGA) is missing in the connector. That's the main video signal on MDA/ …
Re: TVM MD-3N - EGA or CGA Monitor?
Posted on 2021-06-22, 00:01
That's definitely not an EGA card: it only has two two 64Kx4 DRAM chips = 64KB with an 8-bit wide graphics bus. EGA cards use a 32-bit wide graphics bus with (usually) eight 64Kx4 DRAM chips = 256KB. Most likely you have a MDA/Hercules/CGA combo card, and there's a good chance that the TVM monitor …
Re: Dominus: A New Font for DOS
Posted on 2021-06-06, 00:28
Very nice! I will have to give this a try on a real CRT and see if the 1px strokes are thick enough for my old and slightly fuzzy IBM 8513 VGA display...
Re: Most beautiful Dos-Games for a 486...what are your favorites?
Posted on 2021-06-02, 23:04
One thing I have noticed about EGA vs VGA is that while the latter offers more colors, it also increases the risk the graphics will look like blurred or discolored photo's. This is why I think some mid to late 90's games look awful despite their fairly realistic graphics and at the same time think …
Re: CRT - Adjusting Screen/G2 voltage on flyback
Posted on 2021-05-30, 00:42
In the service manuals that I've seen, the procedure for setting G2 is roughly: put brightness/contrast to zero or 50% (it varies?), set the 'service mode' switch to collapse the vertical scan, and then adjust G2 until the horizontal line is just visible. Then adjust the R/G/B drive until the line …
Re: 90's 10/100 ethernet switch
Posted on 2021-05-25, 00:46
I have a big pile of old 8-bit ISA network cards for use with my XT/286/386/486 beasts and they're all 10base2/AUI without 10baseT. I got tired of dangling AUI transceivers off the back (not to mention the AUI to 10baseT converters themselves are getting rarer) and switched to 10base2. The hardest …
Re: Most beautiful Dos-Games for a 486...what are your favorites?
Posted on 2021-05-25, 00:33
I just played a bit of Rise of the Dragon VGA, it looks like it's a pretty good game for the time. The controls are a bit odd though. I think you really need to be into the kind of humor Sam and Max deal with to really appreciate that game. I think Rise of the Dragon also has a beautiful Amiga …
Re: Let's improve video output quality of VGA ISA/VLB cards (First success !)
Posted on 2021-05-19, 23:06
I would really like to see a side-by-side comparison of these cards outputs on both an LCD and an SVGA CRT. I think we're all assuming that the 'jailbars' and other glitches are LCD sampling artifacts, but maybe the card's output is just really awful full stop.
Re: Any suggestions for replacing a tiny power supply in an AT computer?
Posted on 2021-05-19, 23:01
Also I can't measure any voltages off the PSU, it's acting like it's shorted out I think because the Power adapter begins to beep in protest which is generally not good. Your PSU is almost certainly supplying the standard +12V/+5V/-5V/-12V rails. The motherboard has an ISA slot, and each of those …
Re: Let's improve video output quality of VGA ISA/VLB cards (First success !)
Posted on 2021-05-15, 00:41
Looks like your Trident VGA card is older and it has different crystals for each frequency, while the newer tridents have a single crystal and a PLL to generate different refresh rates. Cirrus GD-542x series also uses a PLL with a 14.318Mhz input to generate its pixel and memory clocks. (This was …
Re: maximum refresh rate on matrox millennium; hztool and other issues
Posted on 2021-05-13, 05:00
the monitor overriding works indeed and it looks like one of the eizo monitor presets offers the highest refresh rates; that way the card outputs 640x480@160hz and 800x600@130hz without any issues, not bad for 1995 hardware. thing is, i'd like to be able to set modes below 640x480 as well and those …
Re: maximum refresh rate on matrox millennium; hztool and other issues
Posted on 2021-05-11, 09:36
You need to install the full Matrox drivers. The Millenium drivers that come with 9x/NT4 don't support the full feature set of the cards. Once you've installed the Matrox drivers you'll have access to additional display settings including the ability to override the monitor type and edit the video …
Re: What is your unconscious motive for retro hardware ?
Posted on 2021-05-05, 00:08
I'm particularly fond of my 8088 based machines (IBM PC, XT, and turbo XT clones). They're built from 100% through-hole chips (DIP and PLCC) and most of the 'glue logic' holding everything together is generic 74LS series TTL. I have full schematics and source listings for the IBM gear. The clones …
Re: Help (re)building a 486
Posted on 2021-05-01, 11:01
2. My motherboard only has a DIN port for keyboard and DB-9 mouse interface through an expansion interface board. I have an early PS/2 IBM mouse and keyboard that I want to use here, how would I go about to do that? You can use a PS/2 keyboard with your motherboard, it just requires an adapter …
Re: Let's improve video output quality of VGA ISA/VLB cards
Posted on 2021-04-29, 23:59
Here's a trident tvga8800br which must have one of the worst video quality I've ever seen on a video card. Not only it suffers from various video artifacts, but there are also graphical glitches caused by the ramdac itself. And I think that if I can get this one to look decent and share it with you …
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