Let's look at what's happening:
When you do the 'long-press' to turn off the QMX+, it indeed shuts down, as reported on the screen.
At the end of the shutdown process, the QMX+ firmware turns off (sets to 0) the PWR_HOLD line, which turns off the 12V power rail.? This in turn causes the 5.5V and 3.3V supplies to turn off, and the processor turns off since it no longer has voltage.
In your QMX+, for some reason this is not happening.?
Since the power never went away, the processor never resets and the firmware doesn't start up again, so you have to remove power to cause it to execute the startup sequence.
?
So the first place to look is at the connection of the PWR_HOLD line between the processor and the SMPS.? Since you have a rev1 board, this goes through the angled connectors between the 5V smps card and the main QMX+ board, pin 7 of JP101/102.? I would first use a DMM to check for continuity between that pin on the top of the SMPS to its counterpart on the bottom of main board (it may be too hard to probe the processor pin directly).? Touch up all those solder joints, and see if the problem goes away.
