All:? Latest information in my 2nd QMX saga follows. I know the thread has morphed to related issues, but I am hoping that someone has some more info for helping me salvage my QMX.?
Anyway, I am at a loss as to what to do next and I am not even sure that this rig is salvageable anymore. Fortunately, my original QMX is working perfectly well, so at least I can still get the advantage of this neat new platform. This second rig was originally destined to a friend.
To recap, shortly after installing firmware initially (apparently successfully), C107 and Q108 failed spectacularly. No other damage visible on any boards. On further investigation, the 5 V and 3.3 V busses had pretty reasonable resistances and were not drawing excessive current. The remaining parts of the p/s boards appeared to be working fine, so I powered up the rig (3.3 V bus powered only via on-board p/s's; 5 V bus not powered; display board not connected) and queried the processor via the USB connection. (180 mA initial current, then dropped significantly in a second or so after left encoder push.) A normal connection appeared on the computer and I was able to access all the menus with normal results. The rig powered down normally with the left encoder push. This was all repeatable.?
I then tried to power the 5 V bus separately and it had reasonable current draw- 90 mA. Adding the display board did not change the current draw. I then started the rig as above and then separately powered the 5 V bus. No current initially through the on-board p/s's, but went to 180 mA after left encoder push. Current on the 5 V bus dropped to 28 mA and the 3.3 V bus stayed at 180 mA. Connection to the computer no longer came up and the rig would not shut down after left encoder push. Physical disconnection of the external power was necessary to shut down the rig. No display or display light ever. This is all repeatable.?
Going back to only using the on-board p/s's to power the processor (and no 5 V bus power) no longer allows USB connection to the computer. The current draw no longer drops after a second of so after power up and a second left encoder push no longer shuts down the rig. QMX does not show up as a USB drive on the computer either. Disconnecting power physically now is the only way to shut down the power draw. Again, this is all repeatable. So the main processor is no longer running the QRP Labs firmware, but not sure of the reason for that.
Any further ideas?
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73, Dan? NM3A
