Hello Frans,
The 12 volts feeding the 78M33 comes from the Plug-in PCB #1 (5 volt SMPS board).? Pressing the left encoder grounds the "PWR_ON" flag, which turns on Q103 and Q105 while holding the button.? "PWR_HOLD" comes from the MPU to turn the two transistors on through Q104.? What is not happening is the MPU is not turning on that signal.
I had your symptoms with my first QMX build.? This was after I found a problem with the control board and tried to diagnose it while exposed on the bench.? I somehow damaged the MPU during testing, and that kit is now spare parts.?
Try removing both SMPS boards, the display, and the control board.? Verify the resistance of Vdd to ground on the main board.? For my failed unit, it was 0 Ohms.? I had fried the MPU.
I hope you do not have the same problem; replacing the MPU or scrapping the kit are the only choices.? Hans may make the MPU with his proprietary bootloader available for those capable of replacing the MPU.? I have not yet seen that offer on the web.
73
Evan
AC9TU
