The following is a design problem on the ARGOSY that only
appears after several years.
The band switch shaft in the ARGOSY 1 and 2 runs between the
heterodyne oscillator crystals. In many cases the shaft actually
rubs against the crystal on either side of it and moves the
crystals in their sockets.
The TEN-TEC solution was to pull the crystals away from contact
with the bandswitch shaft by using a piece of sticky tape.
With time the tape dries out and comes unstuck.
Because the crystals hang upside down they can work loose in the
sockets and even fall out.
Another effect of the loose crystal is an apparent faulty band
Solution. Remove the old sticky tape and clean off all traces
of the sticky residue. Install new tape and make sure to pull
the two groups of crystals over at an angle away from the band
while you have the bottom cover off, clean and re-grease the
band switch index mechanism.