[Collins] R-388/51J3 band switch proplem

[Bill Kirkland]

Actually, for bands above band 16, the RF switch doesn't move. You are 
always
using the last RF rack of coils.  If the switch is out of alignment then you 
may
not be able to get all of the sections of the switch to connect.

Check out the manual for the diagrams of the gear box.  There is one disk 
behind
one of the gears and it has a radial pin on it.  At band position 16 this 
pin should engage
a pin on the back panel of the gear box (it sticks out to the front and is 
at the bottom
of the gear box (to the right of the spring for the geneva wheel).  When you 
turn
past position 16, the pin on the back panel prevents the wheel from turning 
and this
holds the RF coil switch in position.  Any play on it and your wafers may 
not be connected
properly.  Fixing it means messing with the gear box.

You may be able to fix things up by loosening up the set screw on the band 
selector shaft,
re-aligning the shaft a tad, and then retightening (assuming this is the 
problem).


Make sure your crystals osc is on frequency. The geneva wheel turns freely 
and can
easily be turned by hand without moving the other gears. If done so, you 
will be selecting
the wrong crystal.  BTW: if the geneva wheel spring is worn, i.e. has a hole 
in it, the
geneva wheel can get out of alignment. In which case you will not be able to 
change bands.
Never, EVER force the band switch. You will strip the soft gears and be sol.


You can check out my notes on the gearbox at the CCA site or at
   http://www3.sympatico.ca/kirklandb/51j_gearbox_v1.pdf

Bill


>From: "Don Worsham" <media at gte.net>
>Reply-To: media at gte.net
>To: collins at mailman.qth.net
>Subject: [Collins] R-388/51J3 band switch proplem
>Date: Mon, 10 Sep 2007 09:06:50 -0700
>
>I have an R-388 bought off of Ebay which has a problem.
>
>I need to cycle the band switch to get the band to to operate correctly. 
>Seems to be
>across all bands. The selected band works but with low sensativity. Most 
>noticable in
>bands above 16 megs.
>
>All of the various waffer switches have been cleaned ( several times) but 
>the problem
>seems to be mechanical as an intertmitant in the circuit wiring.
>
>Anyone have any experince with this?
>
>   "Don Worsham" media at gte.net
>
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