Adrian
Latest update. roWaves contacted me Friday morning with some thoughts.
1. They believe the power button problem may be Q1, Q2 and Q4 MOSFET damaged. Either from current spike or electrostatic.
2. They also think that no amplification and 0C displayed could be related for #1 above, or poor connection on the ribbon cables.
3. They asked me to perform a similar test to your recommendation with the PTT cable T/R short to see if the unit would go into TX mode.
I checked & cleaned all 8 ribbon connectors (all appears in good condition), and repeated the PTT cable test. In both cases there was no change to the units performance.
As I am unable to safely perform SMD component replacement of the MOSFET's they identified, I told them it only makes sense to return the unit for either repair or replacement under warranty.
I'm a little surprised they never asked more about the fan operating in Normal mode at low temperature when I first used the unit and functioning properly.
I did not hear back from them again Friday, so will have to wait until next week for further response (they do not respond on weekends).
73
Scott JK1QLQ