I successfully replaced the PSU in my FM-TOWNS II MX with a standard ATX :
https://www.youtube.com/watch?v=87RLYVn58A4&feature=youtu.beThe adaption was easy, I quickly figured out the pinout of the connector on motherboard (16PIN molex but it can differs in other FM-TOWNS models).
The voltages needed (+5V, +12V, -12V) for powering the FM-TOWNS are present on a ATX PSU along with the +5VSB but colors of wires of the FM-TOWNS PSU mean different voltages compared to ATX.This is the adaption diagram valid for all FM-TOWNS models (but check always with a multimeter):
BLACK=GND ---------------------->same of ATX
BROWN=+5V---------------------->RED ON ATX
RED=+12V------------------------->YELLOW on ATX
ORANGE=-12V--------------------->BLUE on ATX
YELLOW=+5VSB------------------->PURPLE on ATX
On the FM-TOWNS PSU there is also a white wire, this seems to be connected (but not used) to the rear fan connector, we can omit it in this adaption.
As said, the original power switch cannot be used since the FM-TOWNS power up works in a different way, specifically the original switch is a momentary one which briefly shorts the PS-ON signal (BLUE wire on the FM-TOWNS PSU) to GND.So you have to install a switch that keeps shorted to GND the PS-ON signal of the ATX PSU (GREEN wire) for the time the PSU must be ON.I hope this can help you all to replace your faulty FM-TOWNS PSU.If you have any question, don't hesitate to ask.