DB25 networking

Posted on 2020-12-04, 19:16

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I work in the NHS and older buildings often have old female db25 ports in the wall that were used for networking - think they were used for the EMIS LV GP IT system before the servers moved to cat 5 or vt-100 type terminals for connecting to hospital lab servers. Were these point to point serial …

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Re: hdd replacment - sd card, cf card or scsi

Posted on 2020-11-25, 11:09

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

CF to IDE works well in my 486 and is pretty straightforward plus came with mounting bracket. Only issues I had was the bios correctly detecting drive geometry but that was solved by xt-ide bios (it may well have been to do with the fact I dont have a floppy drive and had formatted the cards and …

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-25, 10:01

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

(so wire to vref pin and then a ground point - avoid soldering on the board)

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-24, 10:13

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Okay, here's the relevant bit from the datasheet: LM431.jpg Vref is a fixed 2.5V. I think R5 (1.2Kohm) and R15 (3Kohm) from your board correspond to R1 and R2 on the above schematic. If I'm right, replacing R5 with a 1.5Kohm will yield a voltage of around 3.75V, or 4 volts when using 1.8Kohm. Or …

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-23, 16:37

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Simple is in the eye of the beholder! 😉

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-23, 12:12

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

computerguy08 wrote on 2020-11-23, 11:22: The best you can do is find a reference schematic for the LM431 IC. Finding a schematic for that motheboard is next to impossible. Thought it was a bit optimistic 😉

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-23, 11:07

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Long shot, but does anyone know of a schematic for the board (or schematic library that might have it) online?

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Re: Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-22, 20:42

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Should be possible, but not by altering the jumper as I suspect the only thing it does is to short out the series transistor when set to 5 volts. I think you will have to play with some resistors that bias the base of the TIP31C, or it could be something more complicated using a voltage reference. …

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Voltage adjustment on Socket 3 V4p89SP3 board

Posted on 2020-11-22, 20:18

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi, I want to try and push the voltage up on my 5x86 to get a stable overclock at 160MHz. I assumed the TO-220 package on the board near the 3.3v/5v jumper would be a voltage regulator but it isnt, its a TIP31C power transistor (3.3v is jumper open, 5v is jumper closed) Changing the jumper does …

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Re: Jumpers for 586-160Mhz? (plus how to get DOS to boot with it...)

Posted on 2020-11-21, 21:03

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What I did have to do is increase the voltage. Technically the Am5x86 datasheet I'm reading says 3.3V +/- 0.3V, so I'd be fine going up to 3.6. Of course, to change the voltage you'll need to tweak the voltage regulator on your board. I was about to have a crack at this, but then, googling the part …

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Re: Help overclocking an AMD 5x86 133

Posted on 2020-11-18, 22:08

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Some motherboards/cards aren’t stable at 40mhz and need different settings or even in some cases different cache I agree here. Have you tried switching from Write-Back cache to Write-Through cache in the BIOS? Hmm, no I haven't. Though disabling the L2 cache all together made no improvement. Will …

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Help overclocking an AMD 5x86 133

Posted on 2020-11-18, 16:47

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by squelch41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi, I am trying to overclock my 5x86 but keep failing! It runs fine at the stock 133MHz but if I move the bus speed up to 40MHz, it is unstable. It will POST and I can get to a dos prompt if I dont load the ESS cdrom driver (usually crashes if I do). Pretty sure it is an ADZ varient but there is a …

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Re: Any point upgrading vlb card?

Posted on 2020-11-15, 17:14

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by squelch41

in Marvin \ Video

in Marvin \ Video

Fwiw, music on c&c95 is definitely cd-audio - just put the disc in an audio cd player to check! Nah that's just for your listening pleasure. They had plenty of room on the CD after all The game definitely get's the music from the scores.mix file Ha! Love it! Who wouldn't want to listen to C&C …

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Re: Avance Logic ALG2228 or Cirrus Logic GD5428?

Posted on 2020-11-14, 22:01

by

by squelch41

in Marvin \ Video

in Marvin \ Video

thanks!

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Re: Avance Logic ALG2228 or Cirrus Logic GD5428?

Posted on 2020-11-14, 21:43

by

by squelch41

in Marvin \ Video

in Marvin \ Video

What is the windows acceleration performance like with the ALG2228 vs the cirrus logic 5428? Is it's directdraw performance comparible?

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Re: Any point upgrading vlb card?

Posted on 2020-11-14, 17:46

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by squelch41

in Marvin \ Video

in Marvin \ Video

Fwiw, music on c&c95 is definitely cd-audio - just put the disc in an audio cd player to check!

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Re: Any point upgrading vlb card?

Posted on 2020-11-12, 22:27

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by squelch41

in Marvin \ Video

in Marvin \ Video

My initial thoughts were that it was probably cpu bottlenecking too. I was just wondering about the vga card as the sound is always solid, none of that stuttering you tend to get with a cpu struggling to keep up (sfx - the music is from the CD so that is obviously independent!)

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Re: Any point upgrading vlb card?

Posted on 2020-11-11, 19:58

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by squelch41

in Marvin \ Video

in Marvin \ Video

Your Board and CPU should have enough speed for this game. And C&C is a simple VGA (320x200) game. I played it in 95 with a 486 SX 50MHz and i cannot remember, that is was very slow. Yes, the DOS version is 320x200 and runs smoothly. The win95 version is 640x400 or 640x480 (menu option). It's …

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Re: Any point upgrading vlb card?

Posted on 2020-11-10, 20:42

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by squelch41

in Marvin \ Video

in Marvin \ Video

You cant actually disable sound in C&C, only turn the volume right down and given that the cd keeps spinning for the CD audio, I dont think it disables it. It is a 5x86 but it wont overclock to 160Mhz. It will boot to dos but it rapidly crashes (even with ram timings set with very loose, wait state …

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Any point upgrading vlb card?

Posted on 2020-11-10, 15:42

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by squelch41

in Marvin \ Video

in Marvin \ Video

I'm playing Command and Conquer 95 on my 486 (spec in signature). Scrolling can be quite slow - is that just the CPU or does the cirrus logic graphics card also struggle? It does have directdraw acceleration but presumably pretty slow? Is there any point upgrading the card for games in Windows or …

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