Scott, I would make some voltage measurements.
These can all be done with just the bottom cover of the QMX removed, via the 8-pin and 6-pin power supply connectors you soldered in.? You just need to carefully identify which pin is which.
?
[the 8-pin connector]
1) Vin (JP102 pin 5) - should be the same voltage as your power source
2) 12V (JP102 pin 6) - should be 0V until you push the PWR_ON button, when it should immediately switch to the same voltage as your power source, minus a couple of tenths of a volt.
3) VCC (JP102 pin 4) - should stay at 0V until firmware is loaded, otherwise about 1/2 sec after you press PWR_ON, it should change to 5V.
[the 6-pin connector]
4) VDD (JP103 pin 4) - should be 0V until you push the PWR_ON button, when it should immediately rise to about 3V.? This is what powers the processor on to initialize the USB so you can load your firmware.
5) LIN_REG_EN (JP103 pin 3) - should start at 0V then immediately go to about halve the value as the 12V line measured above.
?
One of those is probably not working as described, which can lead us to the next troubleshooting step.
Stan KC7XE
