If it didn't support MMX, I imagine they would've made a socket 5 board, not a socket 7. It probably does. But this is not a guarantee.

The VRM section looks quite solid, it might suport dual voltage CPUs. I think what you need to do is grab a multimeter and measure...

Measuring of the voltages:
Socket 7 MessaufbauIf you use a load resitor of 100 Ohm between B16 and A17 in the CPU-Socket (in the pic to the upper right), you can measure the core voltage of 2.2V. At the resistor between B18 and A19 (lower right) one can measure the 3.3V supply voltage. (Don't regard the red and black in the picture, you measure between the ends of your resistor, of course). The third 100 Ohm resistor in the upper left is for switching to dual voltage.

CAUTION: before power on close the Socket! The voltage regulators should not be used without load (empty socket)!

The core voltage can be measured between pin 2 (or the housing of the VR) and ground.

(https://www.ccwn.org/~lgeromil/k6_2_e.html).

On my end i had no issues powering boards with no load (empty socket) but i cannot guarantee it would be fine on any board.
My guess, if there is a configurable VRM, it would be configured using jumpers in lower right section of the board, where the voltage regulator is mounted. One more guess, it probably is the longer row, not the shorter one, although can be either or both (shorter would allow for split voltage, longer would choose between levels). I would play with that while the board is switched on and no CPU is plugged in.

Good luck!

or you can download the manual:
download location of manual

Richo wrote:

or you can download the manual:
download location of manual

Even though the board in the manual looks different, it does indicate it supports split voltage down to 2.7v, which should be enough for Pentium MMX chips.

This should clear your doubt.

Unless I'm looking at the wrong manual, that one shows dip switches for setting VC, which I don't have on my board. It also shows both 72-pin and 128-pin memory slots while my board only has 72-pin.

There seems to be numerous versions of PR5, mine is an R2 rev 2.41.

Edit: Thanks lazibayer! That looks more promising!

lazibayer wrote:

This should clear your doubt.

Looks almost perfectly identical, cheers for finding this! 😁
I overread the revision number, maybe I'm becoming too retro myself 🤣

It's a jungle, I tell you! 😁

Thanks to Richo and Tetrium too!

Unfortunately, finding the manual seems to be more difficult... But at least I know the board is supposed to support my CPU.

kenrouholo wrote:

If it didn't support MMX, I imagine they would've made a socket 5 board, not a socket 7. It probably does. But this is not a guarantee.

There's quite a few boards labeled "socket 7" that do not support dual-voltage CPU's.

c0keb0ttle wrote:

Unfortunately, finding the manual seems to be more difficult... But at least I know the board is supposed to support my CPU.

I found a EXE version of the manual but I am unable to open it under 64bit OS.

I could be wrong, but i don't think i've ever seen a 430VX not supporting a mmx.

I've one 430VX that doesn't support the pentium MMX, at least not directly as there is no way of changing the voltage with jumpers. You can however change it by using a VRM, but this is a bit expensive ...

Well, so far so bad:

No beeps, no error codes.

The CPU and memory works fine with my ASUS board.

Might be a dead motherboard. 🙁

I'm running an MMX 233 in my Socket 7 board that doesn't support split voltage. I found a lot of people from 'back in the day' saying that they upgraded systems even using socket 5 boards like this without issue. Mines been running fine, though I did rig a large heatsink fan (non standard) to make sure it keeps nice and cool. I wouldn't recommend it if you didn't need to (I have no choice, it's an IBM Aptiva with OEM motherboard) but if you have no other choice, well it works for me

Nipedley wrote:

I'm running an MMX 233 in my Socket 7 board that doesn't support split voltage. I found a lot of people from 'back in the day' saying that they upgraded systems even using socket 5 boards like this without issue. Mines been running fine, though I did rig a large heatsink fan (non standard) to make sure it keeps nice and cool. I wouldn't recommend it if you didn't need to (I have no choice, it's an IBM Aptiva with OEM motherboard) but if you have no other choice, well it works for me

This is totally fine.

As long as one makes sure the 5V ---> 3.3V VRM isn't overheating because of the increased power draw and that the CPU is decently cooled like yours.

I have never managed to kill a Pentium MMX CPU.

c0keb0ttle wrote:

Unfortunately, finding the manual seems to be more difficult... But at least I know the board is supposed to support my CPU.

th99 might give you some clues.
At least you'll have a start with the jumpers.

Unfortunately it seems like this board is deader than a dodo. 🙁

I've now tried it with a bog standard Pentium 133 MHz CPU and it still refuses to show any signs of life. No POST, not a single beep, no nothing.

How annoying. 🙁

Some experiences of mine that match a totally dead board:
- BIOS chip not fully inserted / poor contact.
- Voltage Step down chips overheated in the past, solder got loose, therefore the Voltage Regulator Module gives no 'Power-Good' signal to the BIOS.