Re: Socket 4, 5, 7 BIOS image collection

Posted on 2021-09-07, 05:26

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

#:20 Manufacturer/Identifier: Soyo Pentium (P54C) Chipset: Intel 430NX (Neptune) BIOS/Version: Award Modular BIOS v4.50G BIOS ID: 08/12/94-NEPTUNE-2A59AS21-00 Filename P54C.jpg File size 961.04 KiB Views 1795 views

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Re: Replacing tantalum power decoupling decoupling caps on vintage motherboards

Posted on 2021-09-06, 19:25

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Now that is an interesting observation. Personally, I was lucky, had no tantalum explosions, just one quietly shorted one that prevented the PSU from starting (Took some time to find out which one it was...). Maybe it's a good idea to put the PSUs on the test bench before deciding whether to use or …

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Re: Voodoo 2 component map

Posted on 2021-09-06, 17:23

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by TheMobRules

in Marvin \ Video

in Marvin \ Video

Instead of creating a new thread, I need assistance finding out two capacitors C50 & C81 on the STB Voodoo2 cards. I can't find an equivalent component map. I need help reading the values and packaging to get the right SMD capacitors. Thanks. Both of those are 10uF 16V. In fact, all the SMD …

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Re: Replacing tantalum power decoupling decoupling caps on vintage motherboards

Posted on 2021-09-06, 17:00

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I think electrolytics will be just fine, in fact I have seen many boards of that era (286/386/486) where they used tantalums and electrolytics interchangeably, i.e. on multiple instances of the same board model you see some with tantalums and others with electrolytics. I think in most cases they …

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Re: ASUS p55t2p4 repair

Posted on 2021-09-05, 20:46

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Take a very close look at the memory slots, I got the "infinite beep loop" once on a motherboard despite the modules being known working ones and compatible. The problem was that the contacts in the SIMM slots were mangled and were likely shorting something there. Replacing the slot fixed the issue …

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Re: Intel LT430TX Motherboard - missing element

Posted on 2021-08-29, 08:50

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What you want is the plain LT1584CT, which is the adjustable version of the regulator. The other variants with suffixes such as -3.3, -3.38, -3.45 or -3.6 output a fixed voltage, but none of those will work here since it is probably used to generate the necessary 2.8V for MMX processors. Here's a …

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Re: Intel LT430TX Motherboard - missing element

Posted on 2021-08-28, 18:11

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have the Gateway OEM version of that board. The part number of the regulator is LT1584CT.

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Re: maintenance floppy drives.

Posted on 2021-08-20, 20:54

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What's the problem with PTFE? I have used silicone with PTFE on lots of floppy drive rails and it works perfectly.

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Re: Gigabyte GA-486VS missing caps

Posted on 2021-08-20, 00:55

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

A single 72 pin FPM SIMM should be enough for a 486, Pentiums do require modules in pairs due to the 64 bit bus. In fact my own GA-486VS works perfectly with a single module. Do any of the chips feel uncomfortably hot when you power the board? All the chips should be only barely warm when running, …

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Re: Modern PSU for Socket 7 PC - suggestions needed

Posted on 2021-08-15, 19:28

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Your case has a power supply with the same form factor as the IBM PC AT 5170, i.e. a "true" AT power supply. You can definitely use an ATX power supply with that motherboard, but there are a few things you need to resolve to make it work: Replace the current power switch with a momentary one that …

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Re: What retro activity did you get up to today?

Posted on 2021-08-12, 21:47

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Smoker's stuff is the worst. I recently cleaned the insides of a CRT that was owned by a heavy smoker and despite having little use and the tube being almost new, it was absolutely filthy. It took me days to clean all that crap, now it looks good but if I get close to it there is still a faint smell …

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Re: GA-486SA: RARE EISA + VLB, or proprietary local bus slots?

Posted on 2021-08-12, 19:31

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Interesting... would bus mastering affect speed for VGA VLB cards? Video bandwidth will be pretty important as I'm trying to test video playback on a 486 VLB build. I remember my cruddy PCChips M601 wouldn't play video w/ a DX2-66, and was horribly unstable at that too. Wonder if it lacked VLB bus …

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Re: Old BIOS modding tools?

Posted on 2021-08-12, 18:41

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is a thread about older (pre-95 or so) versions of AMIBCP that gets bumped up once in a while. In short, many users here have been looking for those for a long time, but no one has been able to find those versions. Even if they were on the Internet at some point they are long gone now and if …

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Re: A 486 system only properly starts while horizontally positioned

Posted on 2021-08-12, 18:18

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm not sure the problem is that the CPU does not go all the way into the socket. 486 CPUs have 4 pins with some kind of "bulge" (one on each corner in the innermost row) which on certain sockets prevents the CPU to sit flush, and it leaves a small gap just as you show in the picture. I think it …

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Re: GA-486SA: RARE EISA + VLB, or proprietary local bus slots?

Posted on 2021-08-10, 20:24

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just found this post from 2013. Apparently Gigabyte did use a proprietary 32-bit local bus on the GA-486US motherboard! But the implementation is described as being "two 16 bit ISA slots in a row", which is clearly not your case: dscf347659q4s.jpeg dscf3490cau8g.jpeg So I'd say there's a high chance …

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Re: GA-486SA: RARE EISA + VLB, or proprietary local bus slots?

Posted on 2021-08-10, 06:11

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There doesn't seem to be a lot of info about that board online. Annoyingly, the TH99 page lists them as "32-bit local bus cards (2)" without providing any further details. However, this blog post from 2009 mentions that board and claims to be using a VLB video card and I/O controller... not sure if …

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Re: Been working a lot, so I have decided I might treat myself to a good VLB video card.

Posted on 2021-08-06, 16:50

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by TheMobRules

in Marvin \ Video

in Marvin \ Video

In DOS benchmarks, the Ark is slightly faster in VGA mode while the Trio should be a bit faster in VESA modes. I don't think you're going to notice any differences in gaming though. In Windows I believe the Trio is considerably better when it comes to accelerated performance. Personally I'd go with …

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Re: Gigabyte GA-486VS missing caps

Posted on 2021-08-06, 15:31

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

EDO RAM won't work with that chipset. For 486 and earlier you want FPM memory modules, only some of the later 486 boards support EDO. Until you get the proper RAM and maybe also POST card you can try the following: remove all memory modules from the board, plug in a PC speaker to the appropriate …

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Re: Gigabyte GA-486VS missing caps

Posted on 2021-08-04, 23:33

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Correct me of I'm wrong but without a schematic trying to find which caps are connected to +5v would be a shot in the dark. Starting with no caps installed and going one by one may be simpler. You can check for continuity between any of the +5V pins of the power connector and the positive leg of …

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Re: Project: Full Can Clock Oscillator Replacement

Posted on 2021-08-04, 21:02

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by TheMobRules

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Excellent! A couple of months ago I spent quite a while sourcing a 50MHz oscillator for a 486DX-50, in the end I managed to find one but it took some time. I don't know how frequently these things fail, but I've already run into a couple of dead boards that I managed to revive after replacing the …

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