It appears there are some bad PCBs in the field.
I started putting some of my purchases together today. First the DigiSpark Pro, which happily blinked away, I modified the Sketch so it blinked faster and at varied rates, all good. Then I loaded up my first Combo Shield, pretty straight-forward, added the OLED display and prepared to load a test program.
The power LED came on, but it wasn't loading, hit Reset, still nothing, then my finger started burning (I was holding it as i plugged in the USB) and I saw smoke, pulled the USB out and the LD1117 flicked off the PCB and onto my desk!
I loaded the schematic and board into Eagle - that chip shouldn't even have been doing anything!
Ok, unplugged the Shield and plugged the USB in again - happily flashing its LED, so main board is at least partially ok, although missing the LD1117.
So, check out the Combo Shield - and I find Vin, GND, and connector pins numbers 7,8,and 11 are all dead shorted to each other.
Nothing at all obvious visually on the board, not easy to follow the copper without a PCB layout.
So, I go to the hot-air rework station and remove everything but the two resistors, and check again, just in case.
Nope, those lines are all shorted somewhere on the PCB.
My guess is a ground fill misalignment. Hard to see under the microscope (especially without a layout) but the drill-spots do appear off-centre on the pads.
When we get boards made here (I work in an electronics company and spend quite a bit of time on board analysis and rework) we usually get 100% e-test, looks like that wasn't done here. Perhaps the others who had similar problems could check their shields to see if the same lines are shorted?
