[R-1051] 5 mhz standard

[Dave or Debbie Metz]

Jerry,
There should be 3 positions on the top of that module:  internal, 
compare, and external.  The compare position was a maintenance setting 
that used the an/urq10 frequency standard ass the comparison .  You 
adjusted the internal 5mhz to get the flicker to something like 1 
flick/second.  This was something you did over several days and made 
sure everything was stable. Then, you knew the internal was calibrated 
to the external standard that was 10 times more accurate than the 
internal standard. All this effort in case the external standard failed. 
As I recall, there was an inside course adjustment and the fine 
adjustment was the one that controlled the flicker rate accessible from 
the top.  You cannot get the compare to work unless you have a 5mhz 
standard feeding into the back of the radio. The other difficulty of 
these units was the internal heater that kept the crystal at the right 
temp to give the accuracy of the 5mhz standard.  That was a setup at the 
repair depot only.  In the mean time, I would suspect that you can  take 
the top off and probably see the course adjustment there somewhere. 
Again, as I recall, the urq10 was accurate to something like 10-8th, and 
the internal standard was something like 1 part in 10-7th. There is a 
separate tech manual for the repair of that module that I believe Robert 
Downs in Houston might have.  WA5CAB maybe??

Once you find the missing adjustment, it takes lots of patience. Small 
adjustments and then wait for a day to restabilize.
73's

Dave
KJ4JX

Jerry Barnish wrote:
> Gentlemen:
>  
> I just found this web page today. I acquired an R1051B
> recently and found the 5mhz standard is not adustable..It is
> 170hz off frequency.
>  
> I would like to get it to where it is supposed to be.
> Having no idea how to fix  it and no schematics as of yet,
> does anyone have advice?
>  
>  
> Jerry WB2CAK
> 
> 
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