[R-390] Re: unable to get past 29MC

[Bob Camp]

Hi

The gizmo that stops the MC knob at the top and bottom end is  
attached down by the main vertical internal bulkhead in the radio.  
The setup uses a series of stamped metal fingers that mesh together.  
When you get to one end or the other of the range the "stack" of  
fingers locks. The easy way to find the stack is to look at the  
bottom of the radio and follow the MC shaft through the bulkhead.

You may have two fingers glued together with some old lube (not  
unusual) and need to squirt them with WD40. If the MC shaft goes  
below 0.0 (500KC to 1 MHz range) then the finger stack simply needs  
to be reset. A very bizarre situation would be that a finger is  
missing from the stack. If so I'm sure a number of us have some  
sitting around for replacements.

There are a couple of other crazy things that could happen. If it's  
not one of the things above let us know and somebody here will have  
an idea.

Either way you are correct, it's a mechanical problem and should be  
fairly easy to fix.

My bet would be on the gunk gluing two fingers together.

     Take Care

             Bob Camp
             KB8TQ



On May 11, 2005, at 1:48 AM, W. Li wrote:

> Have just started to look critically at my Capehart
> R-390A. First thing I noticed was that the MC dial
> does not go past 29MC! I hit a stop just before the
> Veeder-Root comes to 29... weird. The gear train looks
> OK, dial lock and zero adjust are free, and the unit
> works OK and is approx on freq in all bands below
> 28... What am I missing? It's got to be mechanical.
>
> Oh yes, checked all the tube pin resistances to
> ground, and was surprised to find that all were within
> 20% of the Y2K manual... that has got to be a
> first...... Electrically, it needs an alignment, but
> that's for later.
>
> W. Li
> Mercer Island
>
>
>
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