Re: SIMM socket only works when freshly contact cleaned

Posted on 2023-04-02, 13:03

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Could it be power related? Some bad electrolytics/bypasses that are bad enough to deliver required performance, but sometimes being "just ok enough" to support the ram which is cooled down and becoming less susceptible to the power noise?

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Re: Video playback on a 286? - here's how to do it

Posted on 2023-04-02, 08:59

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

dr.zeissler wrote on 2023-04-02, 08:56: This thing works on A2286/8 ET4000 bu8t has no sound. No compression at all 😀

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Re: OPL3 conflicts with standard sound chip on Aztech Sound Galaxy Nova 16.

Posted on 2023-04-02, 08:38

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

By that dash you're indicating the same card under different names (Reveal/Aztech), or you're saying you have two cards, one is Reveal and the other is Aztech? Do you have Adlib Gold card installed, as implied by the error message? If you had Adlib Gold installed at some point (but there is no card …

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Re: HP OmniBook 3000

Posted on 2023-04-01, 11:27

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's hard to make out the state of the pin 28 because of that glow and dust. Check this pin. Is it connected to the same trace (large ground plane) as three pins to the right of it? sd-ide-28.JPG If it is connected to neighboring pins - this may or may not be the cause of your issues, but it should …

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Re: HP OmniBook 3000

Posted on 2023-04-01, 10:58

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can you show the closeup photos of SD->IDE adapter? Top-down photos of each side.

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Re: Inverter problem?

Posted on 2023-04-01, 08:36

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Are you sure it's not the aged CFL tubes? They do become dim with age.

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Re: Sound Blaster AWE32 - MS-DOS and the memory expansion

Posted on 2023-04-01, 07:42

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok, I was under impression that aweutil emulation only uses onboard 1MB ROM. Sure, no game would want to include multimeg sound bank for GM, when the game itself fits on a couple of diskettes. But I was thinking more from the programmer's point of view, having the direct access to the hardware, and …

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Re: Sound Blaster AWE32 - MS-DOS and the memory expansion

Posted on 2023-03-31, 20:14

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'd guess upgrade is useless only when you're using AWEUTIL midi emulation. The game with native EMU8000 support can use larger onboard memory the very same way as Windows would do. Hypothetical alternative midi driver/emulator (anything that is not AWEUTIL) can use the upgraded ram and work better …

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Re: Sound Blaster 16 (CT2940) PCM sound too quiet, FM ok [repaired: two MLCC cracked]

Posted on 2023-03-31, 19:35

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

The U7 op-amp picks the output of either FM synthesizer. Check the C67 and C52 electrolytics directly on the left from the U7, those are connecting U7 outputs to CT2502. I had one electrolytic on 5v rail halfway torn by some side hit, same could happen with those too. Also worth checking larger …

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Re: My first real attampt to get XTIDE on a network card...struggling some

Posted on 2023-03-31, 09:25

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Vipersan wrote on 2023-03-31, 09:16: Hopefully I isolated the right pin... Yeah, that pin: Re: Troubleshooting 386 motherboard, video memory writes clashes with PCM audio playback

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Re: My first real attampt to get XTIDE on a network card...struggling some

Posted on 2023-03-31, 08:24

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That specific CF adapter I see on the photo has the problem, it grounds IDE pin 28, which breaks the ISA bus logic on old PCs where the line 28 in the IDE cable exposes ALE signal from the bus. And it might even work seemingly ok, but make hw misbehave depending on circumstances. The copper around …

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Re: Sound Blaster 16 (CT2940) PCM sound too quiet, FM ok

Posted on 2023-03-30, 12:43

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

Found and fixed :) I've checked the mlcc capacitors around the main CT2502 chip, it's quite often that analog devices expose some regulated reference voltages that needs filtering with external cap. I thought maybe it's dead and shorting the reference, that's why the levels are too low. No caps were …

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Sound Blaster 16 (CT2940) PCM sound too quiet, FM ok [repaired: two MLCC cracked]

Posted on 2023-03-30, 09:11

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

How's the mixing implemented on CT2940, and what are the common failure modes? I have this card, it plays FM nicely in diagnose.exe, but the PCM (both 8/16 bit) are just barely above the noise floor. The card has lots of op-amps, mlcc caps and vias, something that might die or crack relatively easy, …

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Re: Period correct mouse for 486

Posted on 2023-03-27, 19:09

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

rasz_pl wrote on 2023-03-27, 18:16: in higher resolution windows cursor might be too slow? Isn't this is why mouse drivers usually employ acceleration when you move the mouse faster than certain threshold?

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Re: Period correct mouse for 486

Posted on 2023-03-27, 15:05

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

AlessandroB wrote on 2023-03-27, 14:54: PS/2 i always read thet is better than serial on this forum... It's better when available 😀 But here we mostly had "Made in Taiwan/R.O.C." products, so no PS/2.

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Re: How has your interest in vintage computing changed over time?

Posted on 2023-03-27, 11:49

by

by vstrakh

in Milliways

in Milliways

Did not consider myself a retro enthusiast. Not until I've got into FPGA in my line of work. Playing around with Verilog I wanted some reference behavior models for vintage hardware to reproduce in FPGA devkits, and I had the ancient 286 mobo that first had to be fixed from battery leakage. Then the …

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Re: Garbled graphics in all Legend Entertainment adventures on S3 card

Posted on 2023-03-25, 19:20

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

I've tried S3 Trio32, Trio64V+, Trio64V2 - all cards had 8x14 font present (confirmed with diagnostic app from FIX8x14 package). The Spellcasting 101 appear correctly. Either your S3 Trio64V+ is built somehow differently (bios revision, etc.), or there's something more to it. Can you make a photo of …

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Re: Duplicate jumper settings for CPU clock on KVD 486?

Posted on 2023-03-25, 11:59

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It might be that the table does not really specifies the FSB clock, but instead tells the CPU internal clock speed. So the DX2-66 would need 33 MHz clock really, but you look in the table for 66MHz settings from the top half of the table. If you had 40MHz CPU it might be either clock-doubling …

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Re: Need help restoring Biostar MB1320

Posted on 2023-03-25, 11:38

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

TimWolf wrote on 2023-03-25, 02:59: Looks like 1316 1320 1325 1333 and 1340 should have the same components. I have a Biostar MB-1333/40-UCQ, it looks very dissimilar in that area.

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Re: Garbled graphics in all Legend Entertainment adventures on S3 card

Posted on 2023-03-25, 10:32

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

My experience with Legend Entertainment starts well past their EGA games, so could you be more specific with the names? I'm curious and want to try it 😀

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