[R-390] no receive below 8mc.

[Jacques Fortin]

Hi Chuck,

I will be very surprized that the 1.5pF caps had turn bad.
There is more chances that the 51 and 68pF ones make trouble, but if there
is still no change after using new ones, take a look at the tuning slugs for
the Z213-1, 2 and 3.
Only "green" slugs should be fitted there (the ones having a greenish tint).
It happens often that some genius have fitted "brown" slugs there, making
alignment impossible and performance catastrophic.
Ask Russ... !
The RF slugs (Z201 to Z206) are brownish-gray and have a relative
permeability of 10 (which is normal for a maximum tuning ratio of 3:1 and ~
2:1 is used in the R390-A).
The IF slugs (Z213 and 216) are slate grey, or slightly greenish (depending
on origin) and have a relative permeability of 4 (normal for a maximum
tuning ratio of 2:1 and ~ 1.5:1 is used in the R390-A).
I had a Moto 56 RF deck with mixed slugs between RF and IFs, and also slugs
bronze in color that measured 7.3 of relative permeability (no good at all
for a R390-A).....

73, Jacques, VE2JFE

-----Message d'origine-----
De : R-390 [mailto:r-390-bounces at mailman.qth.net] De la part de Chuck
Collins
Envoyé : 18 octobre 2016 23:54
À : R-390 at mailman.qth.net
Objet : Re: [R-390] no receive below 8mc.

The two caps are actually .25% not 2% tolerance

1.5pf
500
WVDC
.25%
ceramic
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