[Johnson] Pacemaker Restoration Problem #3

[Rodger]

David,

It sounds like there is a problem with the switch detent.  It has been 
too long since I restored my Pacemaker for me to remember what style was 
used but when I restored my Desk KW I replaced the detent section of the 
mode switch with a better built unit because the existing detent didn't 
work as positively as I thought it should and I didn't want to take the 
chance of having the mode switch come to rest between selections.  On my 
Pacemaker, it does select bands properly no matter which direction the 
switch is turned so yours definitely has a problem.  I would first try 
cleaning and lubricating the switch shaft where it goes through the 
mounting bushing and also clean and lubricate the detent ball and 
indentations themselves to see if this cures the problem.

If the detent is worn or damaged you can probably find the part from 
another switch that has the same mounting screw distance and degrees 
between selections as your existing switch and use the detent selector 
from the donor switch.  I did this for the Desk KW and I did not have to 
replace any of the wafers themselves.  Mouser and Digikey both have 
pretty good online catalogs with detailed specs so if you have to you 
may be able to find a modern switch to provide the needed part to repair 
your current unit. 

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
>
>
> Johnson mailing list
> Home: http://mailman.qth.net/mailman/listinfo/johnson
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Johnson at mailman.qth.net
>
>
>