[time-nuts] Restoring GR 1120-AB Frequency Standard - Needassist...

WB6BNQ wb6bnq at cox.net
Tue Aug 19 14:42:40 EDT 2008


   Russ,

   Here is another company that has several models of bi-metal TEMPCO type
   switches. Including some very small ones in either a dip (6600 series)
   or TO-220 style (6700 series).

   [1]http://www.airpax.net/site/sensing/bimetal/index.html

   To make Mark happy, if you google various combinations including "solid
   state" you will see some listings for solid state items but I have not
   checked them.  I probably would not go overboard in trying to retro-fit
   with some solid state overkill because I don't think it will achieve
   good enough results.  Besides it would not be a proper restoration at
   that point.

   Bill....WB6BNQ

   WB6BNQ wrote:

        Hello Russ,

        Well, depending upon the size requirement of the thermal switch,
     I
        would consider trying to retro-fit.  One company that makes such
     things
        is TEMPCO [ [1][2]http://www.tempco.com ].  They have several
     different
        kinds and even one model that is adjustable.  There is a nice
     pictorial
        short-form PDF catalog that gives a clear picture of their
     temperature
        switches.  Here is the URL for that :
        [2][3]http://www.tempco.com/Intro2008small.pdf  See the 31st
     page.

        No doubt there are other manufacturers but this is the only one
     that
        comes to mind at the moment.  As for #1 or #2 questions, I would
     think
        of those as a last ditch effort.

        Bill....WB6BNQ

        wa3frp at aol.com wrote:

          I am in the last stage of restoring a 1964 General Radio
     Frequency
          Standard Model 1120-AB.

          I'm having trouble getting the inner oven to work propoerly and
     the
          problem has been traced to a defective thermostat in the inner
     oven.
          In checking, the thermostat is a thermoswitch manufactured by
     Princo
          and is no longer available.

          My options appear to be:

          1. locate a working GR Standard Frequency Oscillator (1113-A)
     and
          replace the entire chassis.

          2. locate a non-working GR Frequency Oscillator and part it out
     as
          needed

          3. find a suitable replacement for the original thermoswitch
     (78 C -
          closes circuit when temperature is reached)

          I was wondering if anyone on this list has any sources or leads
     for
          #1
          and #2 and any opinions on a source for #3.

          Thanks
          Russ WA3FRP

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     References

        1. [5]http://www.tempco.com/
        2. [6]http://www.tempco.com/Intro2008small.pdf
        3. [7]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
     _______________________________________________
     time-nuts mailing list -- time-nuts at febo.com
     To unsubscribe, go to
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References

   1. http://www.airpax.net/site/sensing/bimetal/index.html
   2. http://www.tempco.com/
   3. http://www.tempco.com/Intro2008small.pdf
   4. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
   5. http://www.tempco.com/
   6. http://www.tempco.com/Intro2008small.pdf
   7. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
   8. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts


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