Tin whiskers and other packaging problems

[Pat Pending]

Refugee/Powerdrive. The to18 package (bc107-177) devices that were used in the pid application I mentioned in first post in this topic had a light grey bottom seal, and the "dendrites" (as I have been told its called) looked like rust stains on paint when viewed through with a magnifier, and it presented itself electrically as a very unstable form of leakage. I had originally put this down to corrosion in the bottom of the can or leads. I wonder if this phenomena is similar to what you observed. We were tight and would remove them, clean them up with a small fiberglass brush, dip them in urethane or black enamel, let them dry, and then refit them! If I come across any more examples then I will examine them more closely.

Regards Andy.