Transmitter failure on the nRF51 ?

[Roger Clark]

I've been running a hand soldered prototype board for about a week in an outdoor location where it gets hot and cold (mainly hot), and I noticed it was no longer visible on BLE.

I checked that the nRF51 was responding to the debugger, and uploaded my application with Logging turned on, and as far as I can tell, the MCU is running as it sends strings to the log just like normal.

However I can't detect it at all on BLE, either on an iOS or Android device.

Its possible that the antenna has a dry joint, but I am surprised that if this has happened, I can't detect the device at all, even right next to it.

I presume this is possibly because the external components of the antenna are somehow part of the active circuit and there will be no transmission at all without those components being connected.

Can someone confirm this is the case, i.e a dry joint could completely stop transmission.

BTW. I realise if there was a short on the antenna to ground that could have the same effect, but in this case I think an open circuit is more likely, as it was running for several days before it went wrong

[Michael Antwih]

If your antenna is disconnected from your chip via dry solder, open circuit or component failure; your system will no longer be able to emit rf at 2.4ghz.

Have you probed the circuit to see if you have any open connections or shorts?

When you designed your system did you account for the environment when choosing your components? The failure might be due to component ratings.

Anything that disconnects the chip from the antenna will be seen in the transmission and reception performance. Your device might still be transmitting because could be on a different frequency now since the 2.4ghz radiating element is not in the path.

[Michael Antwih]

Do a continuity check first within your RF path. First make sure you can go from series component to series component and then check all shunts to ground to make sure there aren't any failed components. Are you able to share an image of your RF section? Or you can just place it in the bin but it would be nice to know the failure so the next board up doesn't encounter the same issue.