Nonresponsive with undefined status LED

I’ve got 3 initial prototypes which use an E0 (LTE) as the controller.

First one (top) is operating normally an as expected. Second and third are both nonresponsive and displaying a status LED pattern that doesn’t match anything in the documentation. I have validated that they are receiving the correct voltage (4.8-5VDC) and have tried swapping sources between the 3 and they retain the current behavior. Reset/Mode buttons do nothing except temporarily turn off the status LED. I cannot boot them into safe mode or DFU mode. I cannot reach them over serial w/ CLI.

Any ideas what might be happening with these devices?

@ParticleD, or @mstanley are you able to assist?

I have never seen anything like either one of those flashing patterns. The only thing I can think of is there was some issue in soldering – e.g. a bridge between two pins or between a pin and a via. Or something.

BTW there are those here that would say “never put a powered-up device on conductive foam or bubblewrap”. I have several of my Gen3 devices plugged into the black foam they came in and never had an issue, so I’m skeptical. But I thought I’d mention it :slightly_smiling_face:.

1 Like

Just in case anyone else runs across this - it turned out to be an issue with the solder pads causing several short circuits. We addressed the problem on our process side.