[R-390] 3MC issue updated

[rbethman]

Steve,

Take a step back from the bench.

Thinks about this:

     1) The 3MC works then falls off.

     2) The 20MC doesn't want to play nice.

You have hit a point where you have identified TWO related frequency 
zones that have what in common?

This is one crystal, BUT it is a function of being mixed to get the 20MC.

Somewhere in either the contacts on the MC switch, or possibly a wire, 
and as Curt touches on- trimmer capacitor.

Yes, we KNOW it was completely refurbished.  How long ago?  Has it sat 
without use for awhile?

Bob - N0DGN

On 4/7/2011 2:40 PM, Steve Quinn wrote:
> I posted this a while back, when I shift to 3MC I hear signals then they fade
> but not all the way out.
>
> OR I hear signals for about 30 secs then the band goes dead, dead as a door
> nail.  I have cleaned the xtal and it worked when I put it in my 75S-1
>
> Question:  are the R390A xtals different from the other xtals used in other
> Collins?
>
> I have heard from all to clean this or that, well this unit was taken apart and
> everything was refurbished but the dang 3MC and the related 20MC don't want to
> play nice
>
> Thanks
>
> Steve Quinn