[R-390] R 390A RF Deck problem

[Barry]

> Hi Gents,
> 
> I am new to the list, I 
> am not a Ham but I am a SW Listener and retired EE.? I have a question 
> that has probably been asked before. 
> I have 2) R 390A's and one is very 
> sensitive and the other is not. After considerable testing the newer EAC
> has a sensitivity, MDS, of less than half a microvolt. The older unit Motorola is
> more like 2 to 3 microvolts. I have checked all tubes on the RF deck and
> have swapped tubes from one deck to the other and the symptoms did not change.
> If I swapped the RF decks between the two receivers the problem moves, Now the
> EAC has poor sensitivity. I have changed the recommended capacitors recommended
> and suggested from several web sites. All voltages seem to be OK. 
> Any 
> recommendations on what to check next.
> 
> Thanks is advance and as you 
> guys say, 73,
> 
> Alfred? 

Hi, welcome to the list, and congratulations on owning two of these fine radios.

Have you performed an alignment on the Motorola's RF Deck?

Barry - N4BUQ