Lobotomized M2-ATX as a POL regulator

rsd212 · 09-25-2006, 11:25 PM

Various people (including myself) have reported failures of either the 12V or the 5/3.3V half of the M1/M2-ATX boards. In my case, the 3.3V and 5V seems to be dead, and in my attempt to fix it (on my second board, after sending the first in for warranty), I managed to blow out the PIC microcontroller. Sitting frustrated with a dead PSU, I thought: could I salvage the working half of the board?

Here's what you do to convert your M2-ATX into a 12V POL regulator:
Remove the PIC. Just rip it right out.
If you want the supply to start when IGN goes high: short pins 18 and 15 of the PIC socket.
If you want the supply to start regardless of IGN: short pins 14 and 15 of the PIC socket.
If you want to start the supply using any random 5V source: connect the 5V directly to pin 15.

It will be similar for the 5V, but I cannot test that given that mine doesnt work. Im currently using this to power my Lilliput. Works like a charm.

Only issue: you need a clean IGN source since its now directly connected to the MOSFETS. If IGN sits somewhere between 0 and 12, you may get weird things happening on your output...

gasse · 01-23-2007, 05:31 AM

Clean IGN source?
IGN between 0 to 12... what's the problem? I don't understand.