Electronics > Manufacturing & Assembly

Green shmutz on trimpot screwheads

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My company has recently received PCBAs from our CM that have some sort of green discoloration on the trimpot screwheads.
I do not think that this is oxidation, it seems sort of like glyptol or something. I know that this isn't a lot to go on but I would appreciate hearing from anyone who has seen something like this.
These are brand-name trimpots and a very reputable CM. Obviously we'll be contacting the CM and, if necessary, the trimpot manufacturer.

does it smear? they must be lubricated with a damping compound of some sort to allow for smooth adjustment, possibly with a electrical grease in the wiper area and then a purely mechanical damping grease in the shaft area. they have alot of grades of the stuff. orange green and red are common colors of this grease used for ID purposes

It could be "service cement", sometimes applied to trimpot adjustment screws after calibration to mark that it's done and hold the screw.
I might guess your CM is used to that step, of applying the stuff after PCBA test, and it was done missing the part where you'll apparently do the final test/cal.

Need photos.

HA!  I've heard people talk about pot "glip" for years without knowing it's actually "glyp", short for "glyptal".



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