[R-390] Sensitivity below 8 Mhz

[Barry]

I think this may be similar to the problem Chuck Rippel reported for a different xfmr:

http://web.archive.org/web/20080112212428/http://www.r390a.com/ProbCaps.html

Barry - N4BUQ


 On Mon 05/12/11  5:04 PM , "Pete Williams" jupete at internode.on.net sent:
> LOW SENSITIVITY -390A below 8 Mhz
> 
> G'day list...Apart from the obvious lack of activity in the 17Mhz xtal
> oscillator . I found a fault not mentioned to best of my knowledge in
> theliterature that contributes to low sensitivity below 8 Mhz.
> All voltages checked OK on the tube elements EXCEPT the voltage  at
> E209test point was less than half the listed figure of  around 8 V.
> Altho' the xfmr tuned to a peak, further examination concluded the only
> explanation -apart from tube- od bad ground, would be the feed back
> capacitors in the oscillator circuit or the one in parallel with the
> xfmr.Removing the RF module a pain and a shotgun approach not the best
> practicebut removal and replacement of all 3 produced success.
> Full gain and voltage at test point per manual.
> Caps SEEMED to check OK on a static test.
> ALTERNAYIVE SOLUTIONS WELCOMED .Cheers 
> Pete VK3IZ
> 
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