M4-ATX no shutdown signal

**ThePistonDoctor** · 05-08-2009, 05:42 PM

Hi all,

I searched through the FAQs for something like this but came up empty-handed. I have a M4-ATX PSU powered up on my workbench and for some reason it's not sending the shutdown signal when I kill the power. Luckily I wok at an electronics manufacturing company, so I have a transistorized adjustable linear power supply (TALPS) to play with. Currently I have it hooked up like this:

The TALPS is set at 13v, connected to power and ground on the M4. I have a jumper wire from the IGN terminal to the +12V terminal on the M4. I also have the "thump" harness connected from pins 6/7 on the M4 to the on/off headers on the motherboard. I have dip switch 1 on the power supply ON so it will delay 5 seconds before powering on, and wait 1 min after the ignition is off before turning off the 5vsb rail.

Everything seems to be working fine until I kill the power. I turn it on, it waits 5 seconds, starts the computer and it boots fine. When I kill the power, it isn't sending the shutdown signal. It just turns off like I killed the power on a normal ATX power supply. The instructions for the M4 don't tell me crap, so I'm at a bit of a loss.

Any ideas why it wouldn't be sending the shutdown signal?

**Curiosity** · 05-08-2009, 07:39 PM

It can't send a signal if it has no power. Try disconnecting the IGN wire instead.

**chris350** · 05-08-2009, 08:03 PM

its sounds like you have your ign wire and constant power mixed up....
or you may have the jumper setting in the wrong place. check and double check those things...