Original Product Pages
Jumper Settings (early Revs)
Jumper Settings (later Revs)
Manual from Amptron
The version is printed beside the keyboard.
They seem to have produced everything from 5.1 to 5.6.
Early revisions do have a linear voltage regulator (two large brass heatsinks) and non working USB.
The later (last?) revisions (like the picture above) feature a stronger sitching voltage regulator and working USB (according to some Web-Pages from Amptron).
Amptron statet problems with the USB for at least for Rev. 5.2 and before.
USB should work for Rev. 5.6 onward.
The USB-Controller and Root-Hub is well recognized by Windows, but none of the devices you plug in.
And Rev. 5.3-5.5? I don't know!
Although the chipset should be capable of running current 64 MBit (maybe 128 MBit) technology, at least my Rev. 5.2 board cannot. Every memory is truncated to a fraction of it's capacity.
Best upgrade are old 32MByte SDRam modules with 16 chips on the stick.
I have two of those running in my board, giving 64MB fast memory.
One guy, who has a M550 Rev. 5.6, was reporting, that he has one 8 chip 64MByte module running.
As he is using the same Bios as I am, it seems like there was some sort of design flaw on the early Revs.
The Bios (even the latest) truncates every drive to 8GB.
Use Drive Overlay Software or an OS that does not use the Bios apart from booting (Linux, UN*X, NT,W2K etc.)
Jumper Settings (early Revs):
The setup differs a bit, especially for the CPU-setup.
Don't worry, as everything is printed somewhere on the board.
There are two linear voltage regulators on the board.
The Board Auto-Detects, if there is a Split-or Single-Voltage CPU installed.
One regulator produces Vio, which could be set to 3.3V (=STD) or 3.45V (=VRE) setting.
This should also be the regulator, which drives a single voltage CPU.
The other one is Vcore and can be set to a few voltages down to 2.5V.
As the linear stuff is not that much capable of feeding huge power consumption, BE CAREFUL which CPUs you are going to use.
The other jumpers settings should be the same as for the newer revisions.