Re: My 486 doesn't see different cpu ... can you help me?

Posted on 2021-10-03, 23:15

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

3) For the CPU to work at 25MHz you need to change the bus speed in addition to set the CPU type to SX, I don't see any option for that, maybe an undocumented jumper? 4) Your BIOS may not support that CPU, and IBM is usually very picky and will not allow you to use unsupported processors. 5x86 use …

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Re: Are the PCI slots dead on my PC?

Posted on 2021-10-03, 22:51

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

No, 99.9% it's the capacitors. They are brown Chemi-cons from around 10-15 years ago, which means they are probably KZG or KZJ series, which is a problematic series known to fail early, especially if they are near heat sources. A closer picture of the caps should be enough to confirm that. In any …

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Re: Time to ask before I do some damage Gigabyte GA-486VF rev7

Posted on 2021-09-26, 18:15

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is a page out there that has the download, but I can't find it right now. I have the file though. BIOS is the same as for the GA-486VS, which is not surprising since the boards are almost identical, except for the SIMM slots.

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Re: 486 board with AM586?

Posted on 2021-09-23, 00:20

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

For a 5x86 you need to use the settings for "Enhanced AMD DX4 SV8B(WB)", but you'll also have to find a jumper that switches the CPU internal multiplier to x2 (which works as x4 for the 5x86) instead of the default x3. Otherwise you'll run at 100MHz (33x3) instead of 133 (33x4). It doesn't seem to …

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Re: New AT Power Supplies, 13V on 12V line, voltage increases under a small load.

Posted on 2021-09-22, 05:15

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First of all, that PSU is not FSP at all. While FSP is not a top tier manufacturer, their designs are at the very least decent and their units are packed with components and quite heavy, that one is full of air. Also, that power supply is just a regular bad quality ATX repurposed as AT, you can even …

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Re: PC Chips M912 ver:1.7 absolutely HATES VLB cards but works well with ISA cards

Posted on 2021-09-21, 19:31

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I had to remove the entire VLB slot to fix a single mangled contact, there was just no way of doing it without desoldering... so I agree, better to just replace the slots if you have the tools to do it.

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Re: New AT Power Supplies, 13V on 12V line, voltage increases under a small load.

Posted on 2021-09-21, 19:04

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I don't think those Athena AT units are very good, at least from what I've heard, so pictures of the inside would definitely help. The Startech ones, on the other hand are quite reliable... the protection on those saved me from an incorrectly plugged P8/P9 connector the other day. Another reason may …

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Re: 5.25'' 1.2M drive has trouble with tracks 44-49

Posted on 2021-09-21, 18:55

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, I wonder how reliable these are, not just the motor itself but also the metal "ribbon" thing that is attached to it. I have a few drives with worm drives and they work just fine to this day, but this is the only drive with stepper+ribbon I have, so I don't know how it compares to the newer …

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Re: 5.25'' 1.2M drive has trouble with tracks 44-49

Posted on 2021-09-21, 18:03

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for the suggestions guys. I'll examine the cable and head movement in more detail to see if I notice something strange.

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Re: Floppy Drive Lubrication

Posted on 2021-09-20, 19:07

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You can try to run the IMD Alignment/Test option. Does the head assembly move when seeking a specific track?

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Re: Power Supply Recap?

Posted on 2021-09-20, 07:09

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Righto I'll keep that in mind , is there anything else I should be wary of , like maybe different brands of caps behaving differently voltage distribution wise? Or is that not really an issue? Go with any of the 4 known quality Japanese brands (Nichicon, Panasonic, Rubycon or Chemi-Con). For the …

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5.25'' 1.2M drive has trouble with tracks 44-49

Posted on 2021-09-20, 06:50

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I had created a thread about this drive a while back, but now I've pulled it out again from storage in order to perform more in-depth troubleshooting. Since the problem is actually somewhat different to what I had found before, I'm creating a new thread to avoid confusion. The drive in question is …

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Re: Power Supply Recap?

Posted on 2021-09-20, 06:16

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's made by FSP, should be a solid unit for a P2/P3 after a recap. When ordering replacements make sure to measure diameter because the caps are quite cramped in those units and larger ones usually won't fit.

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Re: Searching for some info on OCTEK HIPPO II 486 mainboard

Posted on 2021-09-20, 01:59

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks, I developed my own tools for this job: https://github.com/DuPAL-PAL-DUmper/DuPAL_Analyzer It's basically bruteforcing, followed by a step of manual massaging (mostly to simplify equations that use feedbacks as inputs). I wrote a small explanation here: https://github.com/DuPAL-PAL-DUmper/ …

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Re: Searching for some info on OCTEK HIPPO II 486 mainboard

Posted on 2021-09-19, 18:44

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Nice job! Could you describe the process you followed to reverse that PAL?

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Re: Where can I find "AMIBCP" (for DOS) ?

Posted on 2021-09-13, 23:28

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First of all, thanks hyoenmadan for contributing those tools to this seemingly never-ending quest of old AMIBCPs! Now, I tried AMIBCP v6.21 with a couple of ROMs I had at hand. These were dumped from 486 motherboards, a HiFlex from 1994 and a WinBIOS from 1995. Unfortunately on both of them I got …

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Re: Have anyone actually gotten hardware damaged due to using old PSUs?

Posted on 2021-09-10, 21:14

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

* If CPUs and video cards had stayed at the Pentium 200 MMX and s3 Trio levels of power usage, Antec would never have been designing 500W power supplies on a tight budget, nor would they be trying to dump all the waste heat from supplying that much power, we might never have had a PSU capacitor …

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Re: Sound blaster 2.0 CT1350 Troubleshooting - very loud noise

Posted on 2021-09-09, 19:01

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by TheMobRules

in Marvin \ Sound

in Marvin \ Sound

That is one of the few cards that requires the -5V line in the power supply, if that line is not present (like in a modern PSU) it would cause symptoms similars to the ones you're experiencing.

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Re: Can someone explain to me about the capacity of old hard drives?

Posted on 2021-09-09, 17:25

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, I really did. It was a 4GB drive, which became 8GB, I used it on a 300mhz celeron, and used it to store limewire content. But he was extremely slow How old were you when you did that? I'm not saying you're lying, but our memories from 20 years ago can become fuzzy as time goes by. As mentioned …

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Re: Building my own Woodgrain 486

Posted on 2021-09-08, 19:05

by

by TheMobRules

in Marvin \ System Specs

in Marvin \ System Specs

Very nice build! Your motherboard seems to be made by MSI, would it be possible for you to dump the BIOS? You can use GETROM or NSSI if you don't have a programmer.

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