Might be a voltage selection for memory. I know the 599 non-LMR models had one.

Here's the amptron manuals:
https://web.archive.org/web/*/http://www.ampt … uals/PM-599LMR/*

They make no mention of the header, so I'd leave it alone.

Yeah, leaving it alone is the best idea.

My guess would be infra-red as a few boards from that time had it and it was usually either near the backplane or by the RAM. I had the same board until it died, I think I still have the modem riser and LAN header somewhere. Know I still have the board but it is long dead and I simply use it for parts like headers and sometimes SMD parts when I do testing as I won't trust them for anything mission critical and have very few other things I would want to steal them from.

I you ask for the board version, it is v1.4. The version number is written in the upper left corner of the board as it appears in the photo.

EDIT: Seems that this jumper/header isn't marked in any version of the manual for the LMR variant of this board model, so is safe to assume that it is a plug/jumper for development purpose only, and you shouln't mess with it. As sidenote, in older non-LMR versions of the M599 there's a jumper JP2 almost in the same place, marked in the manual as selector for the DRAM voltaje.

DNSDies wrote:

Might be a voltage selection for memory. I know the 599 non-LMR models had one. […]
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Might be a voltage selection for memory. I know the 599 non-LMR models had one.

Here's the amptron manuals:
https://web.archive.org/web/*/http://www.ampt … uals/PM-599LMR/*

They make no mention of the header, so I'd leave it alone.

Completely agree it might be a voltage header might be able to tell with a multimeter?

HighTreason wrote:

Yeah, leaving it alone is the best idea.

My guess would be infra-red as a few boards from that time had it and it was usually either near the backplane or by the RAM. I had the same board until it died, I think I still have the modem riser and LAN header somewhere. Know I still have the board but it is long dead and I simply use it for parts like headers and sometimes SMD parts when I do testing as I won't trust them for anything mission critical and have very few other things I would want to steal them from.

Looking through the manual the infra-red port is a different configuration of pins located closer to the rear of the audio connectors.

I also have the DAA modem and LAN adapter working well with this board. The modem keeps a constant 52kbps which is good because there are some free dial up services and I still like to use Faxtalk software.

hyoenmadan wrote:

I you ask for the board version, it is v1.4. The version number is written in the upper left corner of the board as it appears in the photo.

EDIT: Seems that this jumper/header isn't marked in any version of the manual for the LMR variant of this board model, so is safe to assume that it is a plug/jumper for development purpose only, and you shouln't mess with it. As sidenote, in older non-LMR versions of the M599 there's a jumper JP2 almost in the same place, marked in the manual as selector for the DRAM voltaje.

The board is revision 1.4 and it is my speculation that it is a voltage or frequency selector.

I have M599LMR (or something that is identical from the photo). I tried to get it to work with 3x512MB to get 1,5GB as I found in the SiS530 specifications on the Internet but without any success. The only what I got was 1GB from time to time. With 2x512MB it usually hangs on NVRAM BIOS screen. The mainboard manual says that it can get only 3x256MB or 768MB in total.
Because links to photos from the original post do not work anymore I can't tell if it is same as mine.

Thru the miracle called "The wayback machine" of Archive org I give you this from ulysses : sis_530_mobo.jpg = http://web.archive.org/web/20180108013701/htt … mage/3lt2l72fb/
Yes M599LMR supports only to 768Mb ram. The manual says 3 x256Mb or 768MB maximum and that is the max no matter what the chipset data sheet says based on the boards design, which they did for a reason.
If you look at the Asus P5S-B or Gigabyte GA-5SMM that both use the SIS 530 they both have a 768MB max also....
Asus: https://theretroweb.com/motherboard/manual/p5 … d4422121031.pdf
Giga: https://theretroweb.com/motherboard/manual/ga … b8531096811.pdf
Sorry but no go on your 2x or 3x 512MB dimms on this board or any SIS 530 board AFAIK...

Thanks. So bad that they limited it to only 768MB. With 1,5GB it would be really nice piece of hardware!

As I see he has (had?) pretty same versions, when both says 'v1.4' under ISA slot corner. This is mine:

52-0702-001437-00101111-071595-000000-001_V90_8670-H

This site provides information that the BIOS number the board advertises itself matches the M599LMR:
http://www.plasma-online.de/index.html?conten … mb_pcchips.html

If I try to put in 2x512MB it hangs with BIOS as follows:

With 3x512MB it hangs with black screen.