C-Bus eDLT wall unit continuous reboot

Thanks Jason but you give me too much credit... I spoke too soon... the unit is much more stable but I noticed that when slight pressure is applied specifically on the back middle top, it reboots again. It also does the same when delicate twisting forces are applied to the naked PCB when it is out of the housing and front plate removed. Which leads me to believe the problem is not the proximity sensor nor the electronics but more mechanical in nature. Perhaps a poor contact somewhere on the PCB. The components are however so small that I would need a magnifying glass and lots of time to try and find the problem. This has become a bit of a wild goose chase so perhaps better to call it a day for now. Might attempt the riddle again another day.

Thanks for all your inputs it is much appreciated!

 

Sounds like a dry joint issue

 

Chromus beat me to it. Dry solder joint or broken track. Hard to troubleshoot. If you are are a soldering maestro with a very small surface mount tip on your soldering iron, you could just redo the joints on the components probably close to the proximity sensor as a starting point as this seems to be related. It may be thermal and is exacerbated with increased current flow when the sensor is active. An expansion/contraction with heat (caused by increased current flow or general ambient operating temperature increase at wake up or high brightness) at a dry joint may be just enough to cause the dry joint/track crack to open and cause a reboot. A bit like a bimetallic strip if you like. I used to use compressed air (cold) on certain parts of the board to test for such a problem. If you "re-tin" everything and still have the problem, it could be a hairline crack in a track somewhere.

What else would you rather be doing with your time...

 

Definitely not a soldering maestro and my soldering iron tip will probably solder 10 joints in one go So probably not something I should attempt. Out of interest how do you go about using compressed air? Simulate the problem and then cool specific areas on the board with the rapid airflow to force contraction until the problem disappears? Quite interesting, would have liked to experiment with that but the problem is I can't keep the unit in a failed state, it fails and reboots immediately...