[R-390] Sensitivity below 8 Mhz

[Tom Frobase]

I same issue some years ago it was the 10 pf mica.  It checked fine, when
it was replaced the radio worked again.  I remembered finding a reference
on the boat anchor list server ... Tom, N3LLL
On Dec 5, 2011 5:04 PM, "Pete Williams" <jupete at internode.on.net> wrote:

> 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 the
> literature that contributes to low sensitivity below 8 Mhz.
> All voltages checked OK on the tube elements EXCEPT the voltage  at E209
> test 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 practice
> but 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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