I currently use this Bourns rotary encoder (PEC11R-4220K-S0024 Bourns Inc. | Sensors, Transducers | DigiKey) in a device that I hand-solder and assemble.
I’ve noticed that 1 in 10 units, I’ve had an issue with the rotary working properly (either rotary doesn’t work at all or it is jumpy, some clicks aren’t registered). The solder joints look good, properly wetted, full coverage on the pad, pins are all the way through, etc. There is no problem with the button press.
In fixing the units, I just touch each of the pins until the solder melts and readjust the pin just a bit. I don’t add any solder, and I don’t change the pin penetration at all.
This fixes it 100% of the time for some reason. I’m trying to better understand, what is this failure mode? Is it the type of solder I’m using (resin-core, 63-37)? Is it the flux type? Is the rotary pins super sensitive to position?
Thank you in advance.