[R-390] Need value of R235 from a RF deck

[rbethman]

I find an R-236 in the crystal oven circuit from ground on pin 7 in 
series with C-268.  R-236 is listed as 47 ohms.

That shouldn't be an issue unless you are running the crystal oven.

Bob - N0DGN

Flowertime01 at wmconnect.com wrote:
> Craig,
>
> I am not finding R235 on my R390/A TM schematic.
>
> The crystal calibrator isn't quite right! If I use the
> trimmer to zero beat WWV life is good until I turn the calibrator off or
> switch to a different band. Then the calibration is as much as 20-30 KC's
> off. 
>
> When you change bands you are using a different set of crystals from the 
> mixer sections. Any one of the second mixer crystals can be off by any amount.
>
> That's the whole idea of having a crystal to beat against and reset the dial 
> readout 
> with the zero adjust.
>
> But if you were just to switch the MC band up and down and come back to WWV 
> without changing the KV knob or the zero adjust, you would expect WWV to still 
> be close to zero beat (close being under a couple 100 hertz).
>
> Common problems these days are the ground points. The little screws have 
> caught crud after 50 plus years. You just need to loosen the bolts and nut up a 
> turn or two and retighten the bolt and nut to reset the connection. Any one of 
> these ground lugs on the end of a resistor or coupling cap can form a variable 
> resistance that causes problems.  You likely have one of these in the 
> calibration section that is giving you drift. Every time you turn the calibrator on 
> you surge a current through that one crud connection and its instant resistance 
> changes. Just enough to yield a different frequency from the calibration 
> oscillator.
>
> Good Luck with this. It is repairable. It just will just take some effort.
>
>
> Roger AI4NI   </HTML>
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-- 
Bob - NØDGN