[time-nuts] Re: info on the 10811 used in the HP5071A

[Bruce Griffiths]

Belleville washers are conical without waves.
They are often used in aerospace optomechanics.

Bruce
> On 31/08/2023 12:11 NZST Richard (Rick) Karlquist via time-nuts <time-nuts at lists.febo.com> wrote:
> 
>  
> I had forgotten the details.  The schematic is indeed changed
> because the trimmer is now in series with the varactor.  That
> is definitely something I would do; I never approved of the
> trimmer being in parallel with the varactor.  And the MVAM125
> is one of my favorites.  Definitely, I am the one to get
> credit or blame for this :-).  It must have "just worked"
> as I like to say, because I never heard about it again.
> 
> OTOH, I have never seen a complete 10811 schematic with this
> circuit.  I still don't remember having to modify the PCB/flex
> circuit for this.  I am thinking they just kluged it onto the
> regular one.  We would want to manufacture standard 10811's
> from which ones intended for the 5071A could be selected.  Then
> they would be modified with the circuit you showed.  There is
> probably a drawing somewhere showing where to cut traces and
> how to install jumpers to complete the rework.  Almost any
> section of the 5071A, beginning with the CBT is total rocket
> science compared to the tuning rework; and we only sold something
> like 10 a month in those days.
> 
> I didn't know about the "wavy" ("Belleville") washers, but I
> totally approve.  That sounds like something Len Cutler
> would have insisted on (if so, good for him).
> 
> Rick N6RK
> 
> On 8/30/2023 1:40 PM, Corby Dawson via time-nuts wrote:
> > Here is an old post showing the schematic changes required for the 10811
> > oscillator modified to the 05071-60219.
> > 
> > https://febo.com/pipermail/time-nuts_lists.febo.com/2018-January/090824.h
> > tml
> > 
> > Cheers,
> > 
> > Corby
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