So I’ve had a Boron LTE running for a couple months. Repurposed it (no firwmare in either case, just a new case and power supply) and sometimes it either:
Doesn’t boot, LED is dim
Boots to searching for cell signal (flashing green), but before attempt to connect (flashing cyan) the LED briefly dims and unit reboots (endless cycle)
I tried:
Only 5V power supply to USB pin
Only LiPo battery (from a Boron 2/3G)
Both power supply and battery
A different power supply
Monitoring power, strong 5V in all cases, no dips with a min/max Fluke meter. I monitored mA when it does connect; start at about 35 (flashing green), jump to ~110 during (flashing Cyan), fall down to 20 or less (breathing Cyan).
Even odder, when I put this Boron (with no battery) alongside Electron 3G (with LiPo battery) in a parallel powered circuit via perfboard (one 700mA power supply) it ALWAYS boots - just doesn’t boot by itself. I continuity/resistance tested the circuit with the same Fluke meter but don’t see any stray leakage anywhere, and doubt Electron is acting like a capacitor since Boron doesn’t always boot by itself with a charged LiPo battery (since no pins output voltage when LiPo connected).
I actually have 3x units next to each other (signal surveys):
Boron LTE, Electron 3G on one power supply
Electron 2G on another power supply
Both power supplies share one power cord to line AC
Ground wire of power cord tired to both power supply ground wires (-)
Reset pins of all units share the same reset button
Fun fact, pressing any individual reset button resets all units since it’s a momentary contact to ground (and all reset pins are tied together).
Some culprits might be sporadically tripping the reset pin on Boron:
The other Electrons are slightly conductive through their reset pins (like mega Ohms)
Simply inserting Boron (powered by battery) into the test bed (with NO power supplies, power cord ground, nor Electrons connected) will sometimes cause a reset - so perhaps the slight capacitance or difference of potential on the perfbord
In short I think the Boron has a VERY sensitive reset pin tolerance.
True I think Boron has a hairline trigger reset pin… because just touching a connected device with a voltmeter (yes Volts, not Amps) will reset the device. I was just able to measure the “standing voltage” upon pin touch (I have a min/max Fluke) at 0.2V, and that too for like a ms. Almost drove me crazy because problem 1st showed up when I hot-swapped Boron into a board with female headers (no i/o going).
Long story short don’t think you can really hot-swap these.
