Thread: M2-atx hard off when turning ingnition off

Yep, just link it in somewhere along the acc line going to J3 on the M2-ATX . Connect the cathode (striped end of the diode) to the J3 line, and connect the anode (non striped end of the diode) to ground. I put mine near the 15A fuse I installed on the wire just after the splice into the acc line coming out of the ignition key harness. But equally, you could do it right at the connector into the M2-ATX if you wanted.

thanks for the info. rocksteady, does the exact number of the diode matter? i found a diode on an old power supply that says 4007 amonst some other numbers. it's about the diameter of a lollipop stick, I figured it'd be heavier duty than the other little ones on the power supply. also, i drive a 2007 sierra, and my switched line is wired with an add-a-circuit to an "hvac-ign" fuse. I have no idea if it's got a relay, and i certainly haven't wired anything into it. after only a day of testing, these hardoffs already corrupted my windows install (or at least centrafuse which was set as shell). So I'm in the proccess right now of re-installling tinyxp fresh!

Anything bigger than 1N4001 is bigger than what's required for the job, but will still work. 4001 - 4007 are all 1A and the bigger the number the more voltage it will handle.

http://www.diodes.com/datasheets/ds28002.pdf

AWESOME. I wired in a 4006 which was what i had lying around. I haven't even hardwired it yet, i just pushed the striped end into the back of the terminal connector for the black wire and the other end into the white wires terminal. I pushed them right in at the m2-atx itself. And it works perfectly. I didn't even know if the circuit had a relay or not, but i know this was the solution.
I spoke with Chris at mocoso, he said that the circuit must be going to 0v when switching from ign to acc and then a 12v pulse when going to off position. this made sense because I did see the bios screen from time to time on the monitor(indicating a reboot).

Anyhow. Relay or not, the diode solved my problem.
Thanks!

Going to 0V for an instant shouldn't be the problem, so long as the battery feed does not drop too. The M2ATX has a 5sec delay before responding to any "signal" on J3. Remember, J3 is functioning like the on / off switch on the front of the PC (as opposed to the power supply switch on the PSU). The fact the diode fixed it means you were getting a reverse flow from something on your acc line - most likely an inductive load on the circuit.

i used a fuse called hvac-ign, it's on of the only fuses i could find that is switched.

would there be any problems if I wired a 1N4001 diode without a relay?

Originally Posted by rocksteady

Yep, just link it in somewhere along the acc line going to J3 on the M2-ATX . Connect the cathode (striped end of the diode) to the J3 line, and connect the anode (non striped end of the diode) to ground. I put mine near the 15A fuse I installed on the wire just after the splice into the acc line coming out of the ignition key harness. But equally, you could do it right at the connector into the M2-ATX if you wanted.

I am having the same problem and was going to try to wire a diode in as it seems to have fixed issues for some. I want to make sure I understand correctly. The cathode end just touches the acc line (opposed to cutting the line and the diode going "in-line") and the anode side just goes to ground? Is that right?

I had the exact same problem. I installed a power relay for my USB hub and monitor which was causing my computer to hard off after 5 seconds with the M2 PSU. I Installed a 1N277 diode in reverse bias in line on the ACC wire running to my M2 PSU. The wire is between the fuse box (on my car) and the ACC wire going to the trunk. It worked the first time. My carputer goes into hibernate as it should.

Thank you to everyone that was involved with this and to everyone who posted. Keeping the manufacturer and customers aware helps everyone out. I will add that this is my second M2 as the first had a failure in the shutdown module. I am NOT happy with the quality of this product. I do in fact highly recommend the carnetix products. I did another install with a carnetix PSU hooked up to a book sized computer and it works amazingly well.