[time-nuts] Dead 5065A - Some comments - Some questions... (III)

[paul swed]

Ulf I was thinking the 137 Hz was injected differently. But yes its a
varicap on the 5 Mhz signal. Still that same effect can be accomplished in
the PLL feedback loop. I would simply go try these things but can not hack
my one and only 5065. Its working just fine.
A question
The 137 is injected at 5Mhz isn't it multiplied to a FM swing of 2466 Hz at
90 MHz? Granted close in sidebands would still contain 137 Hz.
Regards
Paul

On Wed, Aug 26, 2020 at 3:14 AM Ulf Kylenfall via time-nuts <
time-nuts at lists.febo.com> wrote:

> Paul,
>
> A 60 MHz xtal oscillator divided by 12 and comparedwith the incoming 5
> MHz. Then there is this thing
> how to acheive a good symmetrical FM injecting
> the 137 Hz signal without affecting the loop filterparameters.
>
> Keeping the original design with modern typesof semiconductors is less
> work/effort, provided that the
> unit keeps working...
> The A7 original design used a non selective2nd harmonic detector. And uA
> 709's.That one was easy to motivate an upgrade.
>
> I am a bit lazy otherwise.
>
> As mentioned, the semiconductors that have failed
> in A3 were all dated 1968.
> At the time without knowing the exact types of the JFET'sI replaced them
> with 2N4416 only to discoverthat that was the type HP specified in a
> laterrevision of the A3.
> Best Regards
> Ulf Kylenfall
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