[Johnson] Pacemaker Restoration Problem #3

[David C. Hallam]

Rodger,

The switch sections are tight.  I did try to loosen the tie bolts to see if
I could move the SW6C wafer enough to bring the contacts into alignment.
There was not enough "slop" in the holes of the wafer to accomplish this.

I have applied a small amount of silicone grease to the detent ball and a
couple of drops of synthetic oil to the shaft bushings.

If you remember in the Pacemaker the band switch is directly connected to
SW8 which is the tap switch for the Pi network and indirectly to SW3 and SW6
with dial cords.  In my original posting, I misstated the problem switch
wafer.  It is SW3C not SW6C.  Switch SW6 switches the crystal oscillator and
the RF phase shift.  The crystal oscillator wafer of SW6 is indexing
properly as I have aligned the oscillators.  I don't know about the RF phase
shift wafer as I haven't that far yet.

I think the detent assembly needs to be replaced but the problem is this
assembly is part of the shaft of SW3.  To replace the detent, I would have
to replace the whole shaft or find an identical detent assembly with a
different shaft, cut the two shafts, and use a coupling to join them.

David
KC2JD/4

> -----Original Message-----
> From: Rodger [mailto:wq9e at dtnspeed.net]
> Sent: Tuesday, July 29, 2008 1:35 PM
> To: dhallam at rapidsys.com
> Cc: Johnson List
> Subject: Re: [Johnson] Pacemaker Restoration Problem #3
>
>
> Another thought David,
>
> Are the screws and nuts that hold the switch sections together tight?
> If there is some "slop" here that would cause your problem.
>
> Rodger WQ9E
>
> David C. Hallam wrote:
> > I have run into another problem in my Pacemaker restoration and
> I don't see
> > an answer to this one.
> >
> > I am trying to align the RF amplifier tuned circuits and find
> the contacts
> > on the switch wafers are not making proper contact.  The wafer
> on the SW6C
> > which is for the tuned circuits of V7 plate (RF amplifier) and V8 grid
> > (driver) seems to be the worst.  On 80M it makes proper
> contact.  On 40M it
> > is about 1/2 in contact.  I can tune those two bands.  On the
> three higher
> > band the contacts either just barely touch or there is no
> contact at all.  I
> > cannot tune these three bands.
> >
> > The wafers are all on a common rod and are properly oriented on the rod.
> > The switch detent is on this rod and is solidly connected to
> it.  The is no
> > way to change the orientation of the rod and detent.  If I
> could change it,
> > I think it would solve the problem.
> >
> > The contacts will align properly if I turn the band switch
> counterclockwise
> > from 10M to 80M but not when I turn clockwise from 80M to 10M.
> I know, then
> > turn the switch counterclockwise.  I want to fix the problem
> not live with
> > it.
> >
> > Is this stretch in the dial cord that turns SW6, too much wear
> in the detent
> > or ball, or something else I haven't thought of?  I can't
> imagine it came
> > from the factory this way.
> >
> > David
> > KC2JD/4
> >
> >
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> >
> >
> >
>
>
>
>
>