[R-390] Megacycle Change Stuck R-390

[Alex Hopper]

Hi All,

I have an R-390 that has recently been restored.  It is performing very
well, with one exception...

Last night I attempted to tune up through all of the megahertz bands all
the way to 32 MgHz for the first time.  I got to '30' on the megacycle
change knob, and the knob wouldn't rotate any further to 31.  I could get
it to go slightly towards 31, but it was obviously stuck and I didn't want
to attempt to jam it.

What would potentially be the cause for this being stuck?

Thanks,
-Alex