[R-390] R390A slugology - Problem fixed

John KA1XC [email protected]
Mon, 3 Nov 2003 13:32:44 -0500


Roy,
thanks for the feedback, it helped lead me to the problem with this 390A.

It turned out that it had TWO wrong slugs in the Z206-1 and Z206-2 16-32 MC
coils.
In hindsight, it now seems obvious what the problem was because these two
slugs had a shiny green coating instead of the dull chocolate brown color
that the other RF slugs have; most likely they are from the 1st VIF.

The weird thing is that they appeared to work, sort of. The first one peaked
at the same position as the good slug in T206, but the second one peaked
several turns out with respect to the other. Tracking was also screwed up,
and the gain was also down by almost 20 dB, even with all the slugs peaked
on the same frequency.

I used the substitution method swapping in coils/slugs from a good radio to
isolate the problem, and then borrowed two slugs from the 8-16 MC coils to
test a little more. If anybody has some RF slugs they'd like to unload for a
few bucks let me know, otherwise I'll be putting an order into Fair along
with some other parts I need.

John





----- Original Message ----- 
From: "Roy Morgan" <[email protected]>
To: "R-390 reflector" <[email protected]>
Sent: Wednesday, October 22, 2003 3:43 PM
Subject: Re: [R-390] R390A slugology


> At 04:04 PM 10/22/03 -0400, John KA1XC wrote:
> >Hey guys,
> >In the course of doing some troubleshooting I'm trying to nail down my
> >understanding the slug types/colors in the 390A RF deck.
> >
> >My research seems to indicate that:
> >
> >-all the RF coil and transformers slugs are identical, all bands (usually
> >red/white dots)
> >
> >-all the 1st and 2nd VIF coil slugs are identical (green dots)
> >
> >Sound reasonable?
>
> John,
>
> My notes include this from Bob Camp <[email protected]>:
>
> "The material in the IF slugs is different than the material in the RF
> slugs so don't mix and match. "
>
> This would imply that what you report above is right.
>
> (The R-390 non-A is a different matter altogether.  It has slugs of both
> different diameters and different materials, and may even have slugs
> selected for best tracking in each transformer.)
>
> Roy
>
> - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
> 7130 Panorama Drive, Derwood MD 20855
> Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
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