Grease recommendations for worm gear?

[GanjaTron]

Hi all,

thought I'd join in this discussion as I'm having issues with a HP65 card reader. It worked fine for some 10 years after I replaced the gummy wheel with silicone tubing, but suddenly locked up a few weeks ago. Having inspected it, I now realise the motor is actually loose, with the worm gear no longer centered and wobbling against the frame.

If I align the motor without fully tightening the two screws that attach it to the frame, it runs fine and draws the requisite 180-200 mA unloaded. But if I tighten the screws, the motor experiences severe resistance and draws in excess of 400 mA! I get the impression the worm gear is either too long or its bearing is worn.

Should I apply lube to the worm gear bearing, or should I be looking at the clutch? The motor doesn't slip, so I didn't feel the need to mess with the latter yet. (Nor do I really want to!)

I can also confirm there's some black residue on the worm gear, and the motor is indeed loud and emits a horrible screech sometimes. So I may apply some lube on the worm gear following the advice here, in the hope it doesn't transmit to the card and the head. (I've got some silicone paste somewhere).

Thanks for any suggestions,

--Roland