Repairing a USB port on a bike light let the magic smoke out.

[jld]

I was dumb and plugged by USB rechargeable bike headlight to charge in while it was mounted to my handlebars. My bike fell over and the strain between the USB cable and the light ripped the USB port out of the PCB. The light was off (but charging) at the time, but continued to work with the busted USB port.

I ordered some replacement through hole mini-USB female plugs. I desoldered the bits of the old port that remained, and soldered the replacement port in place with no issues. I confirmed that there was no continuity between any of the pins before going any further.

I plugged the light it into the usb charger, and component U3 burnt up instantly, and the light stopped working.

I'm surprised as the fault was seeming a straight forward physical one, and I turned it into an electrical one.

Can anyone offer advice on what I might have done wrong, and perhaps on what component U3 might be so I can see if I can replace it?

Thanks!

[donkey77]

I can't help with M3:s but seem to remember when repairing a BlackBerry playbook a few years back that it wasn't a standard micro USB connector. Can't remember exactly but I think it was either flipped or something?! Are you sure the one you fitted was correct?

[jld]

I can't be positive, since the port body got torn off and then pins remained in the pcb, but the replacement dropped right in.

Looking at all the options for mini USB B jacks on digikey, they all have their pins mapped through the same way. It's possible there is a different format where the pins get routed differently from board to port, but I doubt it.

http://www.tensility.com/pdffiles/54-00027.pdf

[tsman]

You can try tracing out the 5V and ground pins on the USB connector to see if they connect to the appropriate pins on that chip. It is hard to see from your photos as it has black soldermask and some kind of conformal coating.

[jld]

I’ll give that a shot. I’m new at this, which pins are typically 5v and ground?