Multimeter Amprobe, selector problem

[DisasterNow]

Hello, I have an Amprobe AM 510 multimeter, and I have a problem with the measurement selector: when I select the current measurement in uA scale, sometimes I see the current measurement, other times the resistance measurement. Maybe I need to clean the internal contacts of the selector? Thank you

[DisasterNow]

I removed the card, I see that there is a slight layer on the selector contacts (it can be removed with a finger). Maybe factory fat?

[Gyro]

'Factory fat" is a new term for me, but it is factory (deliberately) applied contact lubricant.

[BillyO]

Mmmmm .. factoy fat!  Droollll...

[EPAIII]

Yes, that is a lubricant. When one part moves in contact with another they can wear. The lubricant was applied to minimize that and maximize the life of the switch. I would not remove it.

Perhaps one of the fingers on the rotor of the switch is a bit bent and not making firm contact. You could gently, I SAY GENTLY, press on each of them in turn to see if that makes the display read correctly.

If this is a new meter, I would try to return it for a refund or replacement. Or contact Amprobe.

[DisasterNow]

I've had this multimeter for 10 years; I will try to check the contacts on the rotor. Ok I'll leave the lube. On electrical rubbing contacts, what type of lubricant is typically used? Thanks