VOGONS


First post, by wacha

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Hi, Vogons community.

I have a 486 board that came with a box of old hardware that I would like to test to see if it even works. The thing is that I am unable to identify it and I've never played around with 486 era hardware before. As I was born in 1990, my area of interest starts with the first Pentiums and very late DOS/Windows 95. I have uploaded a few pictures of the mobo to see if someone can help me.

IMG_20190622_161952.jpg
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https://drive.google.com/file/d/1-88a0_gAm-4Q … iew?usp=sharing

https://drive.google.com/file/d/1-ESzF0eTXM8Z … iew?usp=sharing

My questions are:

- Does anybody know the full name of the board? I can read mb-4d33/50n ver:A but no manufacturer. Google says it might be an Aquarius, but none of the pictures match my board.

- Do you know if the DX2 66 that I intend to use is compatible?

- Can you help me decipher the jumper settings on the board? Say I want to power it on with the DX2 66 and 16Mb of SIMM RAM (two sticks). What settings, if any, would allow me to test the board without breaking anything?

- I see there is no battery, will it power up without one? I've read that 486 era boards are quite picky with batteries, but logic says it should boot, just not save any setting changes.

I have a compatible keyboard, ISA and VLB video cards and SIMM RAM. Should be enough to at least boot, no?

Thanks in advance.

Last edited by wacha on 2019-06-22, 19:12. Edited 1 time in total.

Reply 2 of 13, by wacha

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Predator99 wrote:

Set JP 9/10/11/12 to 33 MHz...connect a speaker or a POST card...and POWER ON 😎

Thanks for the response. What should I do with the cache jumpers?

Reply 3 of 13, by Deksor

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486 DX2 work on most motherboards.

I've not yet seen a board that didn't POST without a battery, but I guess it can still happen.

Yes with video/ram and keyboard you will be able to view the POST screen and play with the bios settings. However of course if you want to boot you need a bootable device such as a HDD or a floppy drive.

If you manage to reach the POST screen, please send a picture of that screen because it can help to find the manufacturer

Trying to identify old hardware ? Visit Ultimate Retro - Project's thread The Ultimate Retro project - a stason.org/TH99 alternative

Reply 4 of 13, by Predator99

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wacha wrote:
Predator99 wrote:

Set JP 9/10/11/12 to 33 MHz...connect a speaker or a POST card...and POWER ON 😎

Thanks for the response. What should I do with the cache jumpers?

Set to 64k...you will not damage anything if wrong.

Reply 5 of 13, by wacha

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Thank you all for your responses. I'll test it and see if it boots. Maybe we can figure out the manufacturer that way.

Cheers.

Reply 6 of 13, by wacha

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Hi guys. Sorry for not reporting earlier, but I haven't been able to test the motherboard yet because the ATX to AT power supply adapter I bought came without an on/off switch. I have ordered another one but it may be still two weeks before it arrives.

Can I start the system without the switch? Something like shorting the power pins in ATX motherboards but with the AT cables?

Here's a picture of the ATX to AT adapter:

https://drive.google.com/file/d/1ls3crb3MzqOS … iew?usp=sharing

Thanks in advance guys, much appreciated.

Reply 8 of 13, by wacha

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Hi guys. Sadly, I think the mobo is dead.

The power supply turns on as soon as I short the two cables, and will remain on until they stop touching. I have tested this by attaching a fan to the power supply. However, the motherboard clicks once after powering on, and then nothing. The keyboard lights turn on for about a second and then they turn off again and I have no video signal nor any kind of sound coming from the speaker. Once the keyboard lights are off, the motherboard makes the sound other motherboards do during POST, but still, no beeps, no keyboard lights, no video signal. I have tested with both my ISA and VLB video cards. I can confirm the RAM is working as is the keyboard.

Just in case, I will recap the configuration:

J1, J2, J4, J5 set to 64k
J6, J7 set to 486
J8 open, as it came. It reads: SHORT DISENABLE PQFP 486SX. I suppose open is the right choice por a 486 DX2
J9, J10, J11, J12 set to 33 MHz

And a picture:

https://drive.google.com/file/d/1-TJi9kqSsAx8 … iew?usp=sharing

Thanks guys.

Reply 9 of 13, by Predator99

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Any shortened pins on the bottom side?

What sound does the motherboard do during POST without a speaker..? This is unusual...

486 MBs are very picky with 72-Pin RAMs. But you should hear a beep even without RAM.

Think for further diag you need a POST-card - 3€ from China.

Reply 10 of 13, by GigAHerZ

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wacha wrote:

...the motherboard clicks once after powering on
I have no video signal nor any kind of sound coming from the speaker.
the motherboard makes the sound other motherboards do during POST, but still, no beeps

Am i going crazy or what? 😖

"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!

Reply 11 of 13, by wacha

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Predator99 wrote:
Any shortened pins on the bottom side? […]
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Any shortened pins on the bottom side?

What sound does the motherboard do during POST without a speaker..? This is unusual...

486 MBs are very picky with 72-Pin RAMs. But you should hear a beep even without RAM.

Think for further diag you need a POST-card - 3€ from China.

GigAHerZ wrote:
wacha wrote:

...the motherboard clicks once after powering on
I have no video signal nor any kind of sound coming from the speaker.
the motherboard makes the sound other motherboards do during POST, but still, no beeps

Am i going crazy or what? 😖

Well, what I mean with "that sound" is when it's checking for devices like Floppys or HDDs, I can usually hear noise just before the floppy disk sound. I can't really describe it as English is not my native language, it's always been a sound I asociate with powering an old computer. Never mind, I´ll get a POST card from China and report back, but shipping's gonna take a while. I'll check again to see if I see any shorted pins, though that's the first thing I checked when it didn't POST.

What I mean by click is exactly that, a click when current is first received. Not a beep from the speaker, but "click". Then keyboard lights for a second, then "that sound", then nothing.

Sorry if I didn't express myself correcly. Thanks for your help guys.

Reply 12 of 13, by evasive

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All of those are MB-4D33/50NR and MB-4D33/50NR-02 I think, not MB-4D33/50N.
ASI (Aquarius Systems Inc) seems to have a weird way of numbering their boards. I'll see if I can dig up some jumper settings.