Tektronix 2235 stiff time / div knob?

[Mjkdar]

I picked up a virtually new condition 2235 tektronix oscilloscope. The time / division knob seems stiff . When I pull out the knob for the time delay, that turns quite easily. Is it normal because it's turning both sets of knobs to be quite stiff? I lubed the shaft of a little, but don't see any points inside to lubricate that would help.

[bob91343]

The shaft may be bent, or the knob may be rubbing.  The worst would be a damaged wafer.

[Mjkdar]

It doesn't appear to be rubbing anywhere and it's not binding. It just seems like a cam or something inside needs to be lubed a little.