I use a magnifying glass to check for solder burs, hairs, etc.. between pins. Use a solder wick or sucker to remove any excess solder (or I just use a rounded oak toothpick which works fine to sweep between pins after melting the solder).
"Touching" the run pin doesn't hurt when soldering headers in (nothing is powered). You do need to ensure there is no stray connection being made to the run pin that shouldn't be there. The Zero 2W is pretty darn robust. I've probably "skipped" off the pin with the soldering iron and scratched across the 2W more than a few times without any adverse consequences. With 60 year old eyes, it's more like "Using the Force" or "Soldering by Braille"![:)]( "Smile")
For some reason the lack of pads and the tiny copper ring around each pin make the zero 2W especially challenging to solder. (tip, up your iron temp by 20 degrees or so (say 275-280 C; 530-535 F). That's a little hotter than I like it, but it seems to help drive heat into the 2W's pin/pad in the 3-4 second heat time I give each pin. To minimize regional heating, I use an every-other pattern working down the side. solder 1st, 3rd, 5th, then 2nd, 4th, and so on.
Also, after soldering and check-over, I always clean the flux off and scrub the solder joints with 99% isopropyl alcohol and and old toothbrush. Just dip about 1/4 of the bristles in the alcohol (that's plenty to do the job) and then scrub the solder joints down. I dry with a cotton cloth (the 99% alcohol actually flashes dry in a few seconds). I give a 30 second additional dry time just to ensure no liquid remains before plugging the 2W in a firing it up.
Give your solder job a good look over and clean-up, if any needed, and try booting again. Report back any findings and your results.
"Touching" the run pin doesn't hurt when soldering headers in (nothing is powered). You do need to ensure there is no stray connection being made to the run pin that shouldn't be there. The Zero 2W is pretty darn robust. I've probably "skipped" off the pin with the soldering iron and scratched across the 2W more than a few times without any adverse consequences. With 60 year old eyes, it's more like "Using the Force" or "Soldering by Braille"
For some reason the lack of pads and the tiny copper ring around each pin make the zero 2W especially challenging to solder. (tip, up your iron temp by 20 degrees or so (say 275-280 C; 530-535 F). That's a little hotter than I like it, but it seems to help drive heat into the 2W's pin/pad in the 3-4 second heat time I give each pin. To minimize regional heating, I use an every-other pattern working down the side. solder 1st, 3rd, 5th, then 2nd, 4th, and so on.
Also, after soldering and check-over, I always clean the flux off and scrub the solder joints with 99% isopropyl alcohol and and old toothbrush. Just dip about 1/4 of the bristles in the alcohol (that's plenty to do the job) and then scrub the solder joints down. I dry with a cotton cloth (the 99% alcohol actually flashes dry in a few seconds). I give a 30 second additional dry time just to ensure no liquid remains before plugging the 2W in a firing it up.
Give your solder job a good look over and clean-up, if any needed, and try booting again. Report back any findings and your results.
Statistics: Posted by drankinatty — Wed Nov 19, 2025 11:59 pm