[time-nuts] 5065A Rb Cavity RX - Varactor repair?

[Bob kb8tq]

Hi

The device in the cavity that takes the 60 MHz up to 6.x GHz is a 
step recovery diode ( SRD ). The actual device used (apparently)
was unique to the 5065. 

One proposed “fix” is to eliminate the whole synth / multiply empire
and replace it with a very high resolution DDS generating the 6.x GHz. 
My guess is that will turn out to be a lot of work ….

Bob

> On Oct 22, 2020, at 9:59 AM, Ulf Kylenfall via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> 
> Strolled into my little lab only to find the 5065A's Red Integrator Limit  
> light on. Control negative fsd. PhotoCurrent OK. No 2nd harmonic. 
> 
> Was just about to power off and start to disassemble the unit. 
> All of a sudden, the Integrator light went out. Control went to zero 
> and by pressing Reset, the unit locked with previous 2nd harmonic 
> level indication. 
> 
> What ever the problem was, I do not know. I guess I can fix (redesign) 
> the synthesizer and replace some semiconductors that have failed 
> but if the problem is in the Rb Cavity RX unit - Varactor - there is a 
> problem. From a similar unit (but without the TED) I can see that 
> some part of the varactor assembly can be dismantled, but then 
> there are a few tiny screws that seems hard to reach. 
> 
> Has anybody repaired the Rx part with the varactor assembly? 
> 
> Regards 
> 
> Ulf Kylenfall 
> SM6GXV 
> 
> 
> 
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