I dont know about the jumpers but is that a burn mark or rust on the middle PCI slot?

Al three PCI slots are working fine. Looks like it was just a speck of dirt.

I think unless someone finds a manual (maybe evasive has something in his HDD ?) You'll have to retro engineer it ...

First of all, I think the jumper right above the CPU controls the voltage as the vrm is right next to it.
Next the three jumpers next to the CPU on the opposite side must be controlling the fsb and finally it the big chunk of jumpers must control the CPU settings.
The rest must be controlling the cache.

Some more competent folks may be able to help you to figure out the CPU settings. (For the CPU voltage you can probably check the settings with the CPU removed and a multimeter)

had one of these a couple of years ago - couldn't get it to post. I think I found jumper settings on stason.org, but I could be wrong. Worth giving it a look.

I managed to find this manual (from elhvb.com). I enhanced it a little bit, so it's more readable:

Added to our website

(can't wait to release this to public ! )

By the way can you please dump your bios ? It may be a different rev than the one available online.

there's at least two variants, one with the ali5119 I/O and one with an SMC I/O chip, yet to be identified. Do NOT just flash any bios on this board before checking what I/O chip you have or you may need to reflash it externally.

Amazing. Thanks! Will dump the BIOS... The bios chip looks like EPROM so not sure it is flashable without programmer....

Deksor wrote on 2020-07-24, 22:44:

I think unless someone finds a manual (maybe evasive has something in his HDD ?) You'll have to retro engineer it ...

Yeah that gift that keeps on giving... I downloaded a lot of stuff over the years it seems...

Hi.
What is the marking of transistor Q5?

Hi,

I have two of the exact same motherboard versons as OP shows in the picture. I also found the user manual on theretroweb (which is the same as the one here). But JP20 which controls the cpu voltage is rotated differently in the users manual than on the board. Any chance anyone knows which pin is number 1 on the physical board?

Guys i found one yesterday its missing the 3 legged vrm chip next to the cpu. Can anyone please provide chip markings ???

Photos below...

yianom wrote on Yesterday, 10:06:

Can anyone please provide chip markings ?

I had a look at https://theretroweb.com/motherboards/s/newtec … smt-smt4321-22a and could not see anything.

I suspect the VRM is an EZ1085 or similar and you should be able to figure out the pins by measuring the voltages. Once installed check the correct voltages are supplied to the CPU socket before installing any CPUs.

Google came up with:

The SMT4321-22A is actually an uncommon Socket 3 486 motherboard manufactured by NewTech/SMT (also known as the TS-486 Terminator), rather than a standalone VRM (Voltage Regulator Module) chip.
If you are looking for the VRM chip on this specific motherboard—likely because you are attempting to configure jumpers to run a low-voltage 3.3V CPU (like an Intel 486DX4 or AMD Am5x86) instead of a standard 5V CPU—here is what you need to know:

• Voltage Regulation Design: Many revisions of this board use a standard LT1085 / LM317 or compatible linear voltage regulator chip package (typically in a TO-220 or TO-263 format) next to the CPU socket to step 5V down to 3.3V or 3.45V.
• Jumper Configuration: You will need to locate the specific onboard jumper blocks that route the power through the VRM circuit rather than passing the raw 5V straight to the Socket 3 pins.

When I was adjusting the VRM on my interposer the best coolers I found were https://www.ebay.co.uk/itm/286041915388

on the other hand Q6 can be some kind of regulator driving missing Q5 transistor

rasz_pl wrote on Yesterday, 13:35:

on the other hand Q6 can be some kind of regulator driving missing Q5 transistor

I can't read what Q5 is, I wonder if it's readable after a bit of cleaning.

I updated my post with what Google said.

rasz_pl wrote on Yesterday, 13:35:

on the other hand Q6 can be some kind of regulator driving missing Q5 transistor

Very likely.

red-ray wrote on Yesterday, 13:31:

• Voltage Regulation Design: Many revisions of this board use a standard LT1085 / LM317 or compatible linear voltage regulator chip package (typically in a TO-220 or TO-263 format) next to the CPU socket to step 5V down to 3.3V or 3.45V.

If that is a linear voltage regular as red-ray was told by Gemini (Google AI) you should attach a small heatsink on it.

Gemini also recommends:
All these are for regulations up to -1.5 V
LM1084 5 A
LM1085 3 A
LM1086 1.5 A (direct replacement to LM317)

A 486 does not consume more than 10 W, so that would be 3 A then (3.3 V x 3), so a LM1085 will be fine. That means like 5 W will be dissipated in the LM1085 and have to be couvered by the heatsink.

Thank You all. I will attach close up photo of Q6 tomorrow.

yianom wrote on Today, 21:01:

Thank You all. I will attach close up photo of Q6 tomorrow.

measure stuff around, all the pins resistance to ground and 12V and 5V rails.