[Collins] cold solder joint??

[Michael A. Crognale]

My WE KWM2 is exhibiting a strange thing. When I tune up the exciter
tuning is extremely sensitive. The RF output will peak but as soon as I
take my hand away it drops to zero. If I touch the know it comes back
and sometimes stays there. If I 'tap' on the knob output comes up and
stays up. I'm thinking that perhaps one of the solder joints might have
gone cold or broken, though I can't fathom why. Any Ideas?
Mike, KC2TU/5