VOGONS


First post, by lalakobe

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Hello all!

Trying to assemble a 486-era pc, can you give me some advice on what motherboard model should I choose?

I want to use Intel A80486DX4-100 CPU
VLB slots
CR-2032 battery (were there such MBs?)

Reply 1 of 12, by debs3759

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I like the Asus PVI-486SP3. 3 PCI and 2 VLB. It can take any 486 ans 5x86 class /cpu.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 2 of 12, by dionb

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Where are you located?
What is available near you at decent price?

It's not as if you just have a smorgasbord of all 486 boards ever made. I'd say it makes a lot more sense to see what is readily available and then choosing which of those comes closest, than to select the ideal board which unfortunately is unavailable or horrendously far away / expensive.

Your requirements are clear - VRM for 3V support, VLB and CR-2032.

I'd suggest flexibility on the last one: so long as a board has external battery support, you can use whatever you want (including CR-2032), which gives you a lot more choice in 486 era than the few boards with actual CR-2032 onboard..

Reply 3 of 12, by Cuttoon

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I assume you already have the CPU?

It's one for 3.3 Volts which will complicate the matter or make it more expensive.

VLB is an additional challenge as they tend to be fickle.
PCI will be even more expensive, plain ISA would be easier to get right, but exclude chips beyond the dx2-80.

I'd estimate that 2/3 of all VLB boards till came without voltage regulators installed, for the later CPUs.

The buggers are easy to spot like here on the left:
http://www.amoretro.de/wp-content/uploads/201 … motherboard.jpg
or less easy like here, upright in the axis of sight, around the socket:
http://www.amoretro.de/wp-content/uploads/201 … motherboard.jpg
(that one is a weird combo - most boards with 3.3 V option will have a ZIF socket and I have that one with a ZIF. Probably all of them should have PS2 RAM.)

I'd say Opti 895 and SIS 471 chipsets like on the boards I linked to should be good, mature options for VLB.

CR2032 battery: Most boards will have the barrel battery or used to until removed. But most will have a header for a battery with cables, allowing you to attach one or simply some battery holder for cr2032. Trivial issue.
AFAIK, the silly custom of soldering on RTC modules with sealed in button battery mostly started in the pentium era.

Brand, model: That one of which you can find at least basic documentation before purchase 😉

I like jumpers.

Reply 4 of 12, by Cuttoon

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debs3759 wrote on 2022-04-09, 18:48:

I like the Asus PVI-486SP3. 3 PCI and 2 VLB. It can take any 486 ans 5x86 class /cpu.

You realize you're a bit of a snob? 😜
Yes, that is a very nice board, if you can get it. It routinely sells north of 100 € but not too often:
https://www.ebay.com/itm/Vintage-Asus-pvi-486 … S-/393860641516
Also, excuse my pedantry, but that is not a VLB board. That is a PCI board with VLB legacy slot(s) that no one should be using, ever.

If it works, this would be a good one:
https://www.ebay.de/itm/255469756465
Voltage regulator with big-ass heatsink, left. (Description says untested. SX-25 in the socket seems a bit suspicious, might have been a test run.)
They sell another one much like that and that they're confusing some of the photos is probably not a good sign:
https://www.ebay.de/itm/255469769972
Buy it now for 115 € with "3 V" in the title is probably as good as it gets:
https://www.ebay.de/itm/334181758105
Dude has 3 of them and seems to know his shit.

My point being: They're not terribly rare if you know what to look for. If you're on a budget, a certain try and error risk is part of the experience. Good luck!

I like jumpers.

Reply 5 of 12, by debs3759

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Cuttoon wrote on 2022-04-09, 22:47:
debs3759 wrote on 2022-04-09, 18:48:

I like the Asus PVI-486SP3. 3 PCI and 2 VLB. It can take any 486 ans 5x86 class /cpu.

You realize you're a bit of a snob? 😜

It's spelt SLOB, or so my friends say 😀

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 6 of 12, by waterbeesje

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I like the rtc boards. Hooking up a cr2032 requires basic soldering skills and some Dremel/cutting tool. If you're willing to mod them, these boards can be a fraction cheaper some times.

Stuck at 10MHz...

Reply 7 of 12, by jesolo

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Another good contender, based on the OP's specifications, is the Asus VL/I-486SV2GX4.
It has VLB, can support the later 486 based CPU's (with a BIOS upgrade), has a CR2032 holder and even has a PS/2 header for mice (which is rare on 486 motherboards).

Obviously, as already stated, price and availability is a major contributing factor. It all depends what you can find for a reasonable price.

Reply 8 of 12, by bloodem

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jesolo wrote on 2022-04-10, 11:07:

Another good contender, based on the OP's specifications, is the Asus VL/I-486SV2GX4.
It has VLB, can support the later 486 based CPU's (with a BIOS upgrade), has a CR2032 holder and even has a PS/2 header for mice (which is rare on 486 motherboards).

Or its sister board, the Asus VL/I-486SVGOX4. This one is very similar to the VL/I-486SV2GX4 (you can even flash the latter's BIOS on it). I have both and the only notable difference is the fact that the GOX4 also has 30-pin memory slots, but other than that they are extremely similar and both have a functional PS/2 mouse header + a CR2032 battery holder.

To the OP: as others have said, these boards are now very expensive, so unless you are extremely lucky (rich), my recommendation is finding other cheaper options. They won't satisfy all of your requirements (at least not out of the box), but modding them will make things more fun. 😀

2 x PGA132 / 5 x Socket 3 / 9 x Socket 7 / 12 x SS7 / 1 x Socket 8 / 14 x Slot 1 / 5 x Slot A
5 x Socket 370 / 8 x Socket A / 2 x Socket 478 / 2 x Socket 754 / 3 x Socket 939 / 7 x LGA775 / 1 x LGA1155
Current rig: Ryzen 5 3600X
Backup rig: Core i7 7700k

Reply 9 of 12, by Cuttoon

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jesolo wrote on 2022-04-10, 11:07:

even has a PS/2 header for mice (which is rare on 486 motherboards).

While not in the OP, that is a rare and definite plus. Didn't even assume there are any boards before PCI that have it.
Thing is, IF there are any "real" (non-experimental) practical optical mice that do support the serial port natively, then they're 99.9 % pure unobtainium.
So, in all practical sense, brace yourself on falling back on a ball mouse. (or you'll have to get some active adapter, for a price)

I'm happy to have a OEM 486 with PS2, those were much more common than retail boards with ps2.

With that Asus, are you sure it also works? Sometimes the headers are there, but don't...

Last edited by Cuttoon on 2022-04-10, 11:48. Edited 1 time in total.

I like jumpers.

Reply 10 of 12, by Cuttoon

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bloodem wrote on 2022-04-10, 11:35:

my recommendation is finding other cheaper options. They won't satisfy all of your requirements (at least not out of the box), but modding them will make things more fun. 😀

He'll be fine. The only "biggish" issue is the 3 V support.
The CR2032, having a dedicated bay on the PCB is merely cosmetic. You can basically attach one to the battery header using only you teeth, old piece of telephone cord and scotch tape - I'd hardly call that modding.

I like jumpers.

Reply 11 of 12, by jesolo

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Cuttoon wrote on 2022-04-10, 11:42:
jesolo wrote on 2022-04-10, 11:07:

even has a PS/2 header for mice (which is rare on 486 motherboards).

With that Asus, are you sure it also works? Sometimes the headers are there, but don't...

Yes, I have mine hooked up to a PS/2 based KVM switch with an optical mouse (which is PS/2 compatible) connected to the KVM switch.

Reply 12 of 12, by bloodem

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jesolo wrote on 2022-04-10, 11:48:

Yes, I have mine hooked up to a PS/2 based KVM switch with an optical mouse (which is PS/2 compatible) connected to the KVM switch.

I also confirm that the PS/2 port (header) works fine on both the VL/I-486SVGOX4 and the VL/I-486SV2GX4 with a "modern" Dell PS/2 optical mouse.

2 x PGA132 / 5 x Socket 3 / 9 x Socket 7 / 12 x SS7 / 1 x Socket 8 / 14 x Slot 1 / 5 x Slot A
5 x Socket 370 / 8 x Socket A / 2 x Socket 478 / 2 x Socket 754 / 3 x Socket 939 / 7 x LGA775 / 1 x LGA1155
Current rig: Ryzen 5 3600X
Backup rig: Core i7 7700k