[Premium-Rx] WJ 8617 Synthesizer Problem (?)

[David Schofield]

Hi Rye,

I think this may be some kind of "stock fault". My receiver behaves 
exactly the same as you describe whilst cold. As soon as it reaches 
operating temperature after being on for 10 min or so everything is OK. 
Have you tried letting yours warm up and seeing if it returns to normal?
With this sort of fault I would strongly suspect capacitor failure 
either within the PSU or the synthesizer itself.
I have a copy of the technical manual which can be obtained from 
http://www.vintagemanuals.com/ do a search for the 8618B essentially the 
same Rx.
I can scan small sections for you if it will help you locate the fault.
I am also going to take a look at mine in the near future so will let 
you know what I find. So far I have been lazy and just left it on to 
warm up before use but would like to get to the bottom of it.

Cheers,
Dave.S.


Rye Gewalt wrote:
> I'm wondering if anyone on the list had any experience with the synthesizer
> in the Watkins Johnson WJ8617?
>
>  
>
> I have a lovely B-17 model that has suddenly lost the ability to tune in
> anything under 1 MHz steps.  The display shows the full frequency and all
> other functions seem to be working so  suspect that the problem is
> associated with the second LO --- probably out of lock.  In fact, the radio
> is kind of 'drifty' in that when I listen to signals at the 1 MHz  steps --
> I can hear them drifting around as if the VCO is not being disciplined, but
> is running.
>
>  
>
> Perhaps one of you have had experience with such a fault or could point me
> to somebody who might be helpful.  I've got the manual and all (most?) of
> the extender cards etc. and a pretty good shop but, I'm kind of reluctant to
> dig into the radio until I've checked with the experts to see if this is a
> problem that has a known fix methodology.    --- no point in reinventing the
> wheel and maybe screwing up something else in the process...
>
>  
>
> Any help would be greatly appreciated.  
>
>  
>
> In the meantime, I will spend some time checking supply voltages etc.
>
>  
>
> Rye
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