Some M2-ATX issues

**strikeback03** · 05-18-2009, 11:30 AM

So after an M3 proved to not be stable on my LF2 board, I installed an M2. When running it seems OK, but if I tell the system to shut down (via the start menu) it restarts after shutdown, then if I tell it to shut down again it shuts down and stays off. Also, with the ignition pin connected to an actual ignition-on line, the computer hard-powers-off as soon as the ignition is turned off. However, if I use a switch to cut IGN power to the IGN pin before turning the ignition off, it does a proper hibernation. Anyone ever experience either of these?

**MeeM** · 05-19-2009, 11:23 AM

I have experienced the first issue - after shutting it down, it starts up again, and if I tell it to shutdown again, it stays off. Even when it's on, if I hold my power button for a few seconds, it turns off, and then turns on again. I have to hold the button again to turn it off for good. (The system is set to hibernate if the power button is pressed, and this works perfectly whenever I press the power button, or if I turn the car off. When I turn the car on, the PC always resumes from hibernation properly.)

I haven't experienced your second issue. When I turn the key to off, the car PC starts to hibernate about 5 seconds after. So that's fine for me. It's never stayed on longer than that.

**soundman98** · 05-19-2009, 11:35 AM

your first issue sounds like a settings problem-- is your mother board setup to resume on ac restore? this could cause that.

for the second issue, it sounds like you are using a igition circuit for both a trigger and power supply lines. the power input should always have a constant 12v. regaurdless of ignition postion.

**strikeback03** · 05-20-2009, 09:49 AM

I'm pretty sure the BIOS is set to stay off on AC restore, I'll check later. The system did not work this way with the M3-ATX (that had a different problem, despite being set to hibernate after 5 seconds, it usually waited a minute).

The main power is on a constant 12V line, it is run to my distribution block from the battery. I currently have a switch installed between the IGN line and the IGN pin on the PSU, if I flip that switch off to cut power to the IGN sense on the PSU before actually turning the car off it works properly. But if I simply flip the ignition off (which should be the same thing) it cuts out immediately.

**MeeM** · 05-20-2009, 11:16 AM

Perhaps there's a relatively higher voltage running down the ignition line when the car is running? The M2-ATX might be interpreting the higher voltage as a "more appropriate" signal and hence it responds correctly. If possible, measure the voltage and current on the ignition line with car off and car on. If there are any differences, try to replicate them with a battery (and current limiting circuit) as the ignition source and see if the M2 responds in the same way (keep the switch in-line).

**DarquePervert** · 05-20-2009, 01:57 PM

Break out the multimeter and measure the voltage on the ignition line with the ignition on and then with the ignition off (with your switch in the on position, of course).
Ignition on should be ~12vDC.
Ignition off should be 0vDC.

Anything else could present a problem.

**strikeback03** · 05-22-2009, 11:01 AM

yeah, I already checked that, reads the expected. The multimeter doesn't respond fast enough to see if there is some transient when I switch it off, don't have an oscilloscope. I'll try measuring to see if the IGN is higher than the always-on tonight or tomorrow.