[R-390] Mechanical Filter Issue

[Leigh Sedgwick]

Thanks all for the responses to my questions.  I appreciate
the help.  A couple of finds today.

1.  Either Figure 3-6, page 3-16 of the Y2K-R2 manual is
wrong or my R-390A is wired differently than most.  All of
the input trimmers shown in this figure are correct but the
output trimmers are all incorrectly marked.  This is what I
find:

FL502  2 khz filter - input C567/output C570
FL503  4 khz filter - input C566/output C568
FL504  8 khz filter - input C565/output C571
FL505 16 khz filter - input C564/output C569

Can anyone confirm these findings?  If so, might be a
candidate pickup for revision 3 of this fine manual (thanks
to all for the hard work on this great resource).

2.  Based on going through the 2 khz filter circuit, it
appears the 2 khz filter is indeed bad and I am in the
process of replacing it, ugh!

3.  I looked at the slug racks in the RF deck, and they all
appear to be identical (i.e., RF versus IF).  The RF slugs
are all marked identically with both a white and red dot. 
The variable IF slugs have no markings.

Thanks again....

73 de Mike
K7PI

Leigh Sedgwick wrote:
> 
> Hi Gang,
> 
> On the a different subject.  My restoration R-390A project
> is just about finished.  I rebuilt the RF deck and recapped
> the IF deck and AF decks.  The smoke test was positive with
> signals on all bands, although it is way out of alignment.
> But I have a couple of issues.
> 
> 1.  Three of the four mechanical filters appear to work
> fine.  But, when I switch to the 0.1, 1, and 2 bandwidth
> positions, there are no signals.  Is there any quick check I
> can make to ensure it is the 2 khz mechanical filter and not
> something else in the circuit?  It looks like a bit of work
> to replace and I would hate to go through that effort only
> to find out it is actually something else.
> 
> 2.  I tore the RF deck apart with the idea I would get it
> rebuilt within a week or 2.  No such luck...work issues
> caused a significant delay of almost a year before I was
> able to get back and finish it.  During that time, I lost
> track of the ordering of the slug racks and was forced to go
> with a "best fit" approach to reassembling them.  Other than
> the fact that the alignment is totally hosed up, will I be
> faced with any other issues, i.e., are they all identical or
> are there differences I cannot see visually.  I saw
> something on the FAQ page that some are different.  They all
> looked the same to me.
> 
> Thanks for any help.
> 
> Happy New Year
> 
> 73 de Mike
> K7PI
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