So this was a totally self inflicted event, but I blew the PWR_HOLD port on the CPU. I don't particularly like the flex the left part of the control board has when pressing on the left encoder so was experimenting with different materials between the encoder and the 5v SMPS connector.
Symptoms afterwards were QMX would power on but as soon as the left encoder was released it would power off immediately. Initially I thought the PWR_HOLD port or PWM_5V port or both were blown. Narrowed it down to the PWR_HOLD port only. Hmmm, can I fix this. First thought was to simply change which port PWR_HOLD is utilizing but alas no access to firmware. What else to do? Only restriction was that I wanted changes only to the main board and not the SMPSs as they were fine. So I decided to cut the PWR_HOLD 90 degree angle pin which would severe the PWR_HOLD port from the 5v SMPS. Then run Vdd to the upper part of the severed connection so that PWR_HOLD on the SMPS was always at Vdd. I picked Vdd off C429 and ran the line under the 5v power board connectors. Works perfect. Well almost. Now when powering off I have to actually remove power after I see the "Shutdown" message. Fortunately my battery supply has a switch so this is no problem. Every thing else works perfect. May still add a 100k resistor from the port (bottom of the cut pin) to ground - not sure it's necessary though. This rig will remain my personal rig and not be sold.
Lesson for today: Be careful out there, especially when probing a powered rig.
As a side note you can see that I don't try to lay the LPF toroids flat. There is room to angle them and it makes any adjustments easier.
-mike/w1mt
