maybe this is the board: https://www.ultimateretro.net/en/motherboards/640#downloads

(listing says MB-4DUVC, but the first photo there is labelled MD-4DUV-VER: 2.1. Looks like most jumper settings are shown on the silkscreen).

Thanks, my only concern is have I potentially got a CPU that won't work? This board does have jumper settings for 486DX and DX4 but no mention of DX2 which I have bought a Intel 80486 DX2-66?

DaveDoc1984 wrote on 2022-04-03, 21:02:

Thanks, my only concern is have I potentially got a CPU that won't work? This board does have jumper settings for 486DX and DX4 but no mention of DX2 which I have bought a Intel 80486 DX2-66?

Yes it does, the CPU jumpers for a Intel DX2 are same as Intel DX and AMD DX2. Only if an SL cpu are they different and the voltages could be too.
For Intel DX2-66 use the 80486DX or AM486DX2 cpu settings, you will notice they are identical. Just be sure to set CPU volts to 5v as Intel DX2 are all 5v AFAIK.
There are some AMD DX2 that are 5v and some are 3.3v....

Thanks Horun 😀 in that case I think I am pretty much there. There are some things from back in the 486 era that I had forgotten about 😀.

Sorry to ask another question but I am very confused. The motherboard Manual linked here makes reference to Jumpers that don't appear on my board at all e.g. I can't find any Jumpers marked up as J30, 31, 32, 33, 34 and 35.

Also the Silkscreen doesn't mention DX4 yet this manual does and gives jumper settings for it, does it support DX4 (if I was to get a DX4 CPU in the future) or no ?

Cool! That's the same board I have! Aquarius brand 😀

I can confirm the jumpers do match the link and it does work with almost any CPU you throw at it.
I've ran it with an SX, DX, DX2 (DX setting), DX2-SL (at 3v) DX4 (Intel and amd), 5x86 (amd and cyrix).
5x86 does display weird post strings (like SX-66) but it works flawlessly.

waterbeesje wrote on 2022-04-07, 20:39:

Cool! That's the same board I have! Aquarius brand :) […]
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Cool! That's the same board I have! Aquarius brand 😀

I can confirm the jumpers do match the link and it does work with almost any CPU you throw at it.
I've ran it with an SX, DX, DX2 (DX setting), DX2-SL (at 3v) DX4 (Intel and amd), 5x86 (amd and cyrix).
5x86 does display weird post strings (like SX-66) but it works flawlessly.

Thanks so a DX4 will work?

I can't find JP35 etc though?

Just had a closer look and it turns out there are differences between the DUV and DUVC where they shifted one of the two big jumper blocks by the CPU to make way for the voltage select jumpers. You can make them out in this photo of the DUVC: https://i.ebayimg.com/images/g/KlEAAOSw0R9gRC49/s-l1600.jpg (looks like the design allows for either 30 or 72 pin RAM sockets).

So the jumper manual for DUVC won't be a lot of help. There may still be some options for voltage selection. Look for connections between any of the blue resistors, the jumper pins and the voltage regulator. In the photos of the DUV version it looks like there are 3 blue resistors, which are higher precision than the usual resistors and often used for setting the output voltage of an adjustable regulator.

So back to my original question that being the case (If I can't be sure what jumpers to set, I risk frying the DX4...)

Is there a Manual / Jumper setting list for the DUV rather than DUVC?

Not that I can find, sorry. With a bit of time and a multimeter it should be possible to figure out if any of the jumpers are voltage selects, and what the voltage options are.

Where would I measure to make sure its doing 3.3V for when I do get the DX4? The fact the board makes no reference to it concerns me.

Figured it out. The same Voltage Jumpers referenced in the DUVC manual appear to set the VCC to the CPU to 3.3v on my DUV board so that is good.

Just now need to know which other jumper settings to set for a DX4.

So figured out the DX4 settings and its working. Shows DX4-S on boot up and 100MHZ

Next question, where on earth do I connect a CMOS Battery? There is nothing onboard (no battery compartment or terminals) so how would I do this?

DaveDoc1984 wrote on 2022-04-11, 13:06:

So figured out the DX4 settings and its working. Shows DX4-S on boot up and 100MHZ

Next question, where on earth do I connect a CMOS Battery? There is nothing onboard (no battery compartment or terminals) so how would I do this?

Your motherboard photo, pls. Link in your first post is “forbidden”(((

I have just clicked that link and it took me straight to the photo?

1) internal battery socket place
2) external battery pins

I have run into a bit of an issue which I think is Cache Related (External rather than Internal CPU Cache).

The motherboard has a Bank 0 and Bank 1 of Cache. Bank 0 is the only set that is populated as well as the TAG.

All slots in Bank 0 have W24257AK-15 Chips in them and Bank 1 is completely empty.

I have set the jumpers to reflect that only Bank 0 is populated and from the Spec sheet of the Chips its 32k x 8 so 256K? I have set my jumpers to reflect this but the machine will start to initially boot the OS and will halt a few seconds in. If I DISABLE External Cache, the machine then works fine. Any ideas on what could be wrong? Could 1 or more of the Cache chips be faulty?

DaveDoc1984 wrote on 2022-04-12, 09:46:

I have run into a bit of an issue which I think is Cache Related (External rather than Internal CPU Cache). […]
Show full quote

I have run into a bit of an issue which I think is Cache Related (External rather than Internal CPU Cache).

The motherboard has a Bank 0 and Bank 1 of Cache. Bank 0 is the only set that is populated as well as the TAG.

All slots in Bank 0 have W24257AK-15 Chips in them and Bank 1 is completely empty.

I have set the jumpers to reflect that only Bank 0 is populated and from the Spec sheet of the Chips its 32k x 8 so 256K? I have set my jumpers to reflect this but the machine will start to initially boot the OS and will halt a few seconds in. If I DISABLE External Cache, the machine then works fine. Any ideas on what could be wrong? Could 1 or more of the Cache chips be faulty?

Photo pls!

Here is the picture of Bank 0 and Bank 1.