HP-65 1333A20064 serviced by someone ?

[teenix]

It may be oversized and/or eccentric o-rings causing them to put excess pressure on the idler roller and card on each rotation of the drive wheel. Awful stuff as it loads up the motor which will draw excessive current from the sense chip. Both are well on their way to be eligible for pensions so not worth stressing them. If the coupler was out of center, then you would feel some nasty vibration and will eventually damage the motor bearings which are probably suffering arthritis by now, so also to be avoided.

I have repaired quite a few gummy wheels now using o-rings and while they work, most needed attention before fitting and using them. This was a size reduction to make them work freely in the mechanism, otherwise I get symptoms similar to yours. Maybe the original drive wheel material was exactly 1/4 inch, maybe not, I don't know. Either way, because it puts outward pressure on the o-rings when they are fitted to the drive wheel, they expand beyond their original size and I think this is the problem.

When you fit the drive wheel on the axle (without the motor in place) you need to check that it turns freely on any axle adjustment setting. One the widest axle setting, the card should be able to be pushed into the slot quite easily while still turning the drive wheel. This should get progressively harder as the adjustment is made. If you fail to realize this, then excess pressure will be placed on the card during transport through the reader. If there is too much pressure, then you might also risk breaking the tiny axles on the idler roller and that will hurt.

The width of both o-rings can also exceed the drive wheel axle width and cause the outer o-ring side to drag on the side of the wheel well opening.

The other thing worth noting is that there should be a tiny sideways movement on the worm gear shaft when the motor is screwed up tight. If this play is not there then excessive side pressure will be placed on shaft and perhaps the motor bearings.

I have this info available in the Classic Notes PDF.

It's interesting that the o-ring closest to the metal wheel shoulder barely touches, or doesn't even touch the card. It really just serves as a spacer to keep outer one parallel.

cheers

Tony