Argon switching on only when powered via 3.3V pin


I got a Particle Argon recently and was using it for a school project. Everything was working great and I was powering it off a small LiPo and USB depending on what was most convenient. I had to use two digital pins to connect to my device and soldered them on to I/O pins directly because everything had to fit into a small form factor.

I wanted to reuse the device, so I desoldered the previously connected pins. Since then, I could not power the Argon using either a LiPo or the USB connection. It downright fails to start. However, when I connect the output of a LiPo directly to the 3.3V pin and ground, it switches on the device and as far as I can tell, everything is working properly (connects to wifi, blinks led, etc).

When desoldering, I made sure not to apply the heat for too long for fear of frying anything. But that is the only explanation that I can think of for why the USB and LiPo power sources are not working. Do you also think this is the reason and is there any way I can fix my device?

EDIT: I used a multimeter to check the potential of the VUSB pin and Li+ vs ground when connecte via USB and LiPo respectively, and they read the potentials that they should (~ 4 V and 5.2 V). I am not sure if this information is of any use, but hopefully, it will help with troubleshooting.

That’s not a good idea since the 3v3 pin can only take 3.6V max but a fully charged LiPo will give you 4.2V.

It may be that the EN pin is held low somehow, which would prevent the 3.3V regulator from being enabled or your regulator is dead.

Hmm, ESD is at least one other potential cause for death of electronics :wink:

It might be helpful to know which pins you soldered/desoldered. Also, have you checked very carefully to be sure you didn’t leave a solder bridge between pins on your Argon?

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So, the pins I desoldered were D3, A3, the 3.3V and GND. All were used to interface with the sensors I was using and power them. All the others pins were never touched by heat to the best of my knowledge.

I did check for stay solder brides between the pins. Definitely a possibility. I will do so again and am hoping that this is actually the case. I really would not want to buy another Argon :frowning: