"Paul P" REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote in
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"Richard Knoppow" wrote in
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On Apr 13, 6:40 pm, "Paul P" REMOVE paul @ REMOVE ppinyot
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REMOVEcom wrote:
I am restoring now aligning a S-38. Yep, all caps and
resistors replaced
except the domino caps and tubes tested, bias voltages
with in spec. I gave
up the alignment for now. I am having trouble aligning
the Band 2 at 5mc.
The oscillator just dose not want to go high enough.
Perhaps a good night's
sleep will help.

Questions:

1) What is the oscillator offset (add or subtract the IF
freq 455) for the
four bands? Are any bands different from the others?
Broadcast is just
fine at frequency plus IF (455).

2) Are the domino caps paper inside or mica? They are NOT
Micamold. There
are three of four of them. I was going to replace them
next and heat gun
the coils.

http://www.nostalgiaair.org/PagesByM...2/M0008862.pdf

Thanks,
Paul P

The postage stamp caps are mica but probably not
silver mica.
If all the other frequencies come in the problem may
be that
something has shifted in the band 2 oscillator coil. Most
of these
coils have a couple of spaced turns to adjust the value.
You will have
to juggle between the coil and the trimmer.
The S-38B LO is 455 khz above the signal frequency on
all bands.\


Thanks Richard,

Yes the whole band is shifted. I will look at and chase
the coils.

One point of clarification. So that would make 5 MHz look
like 5.455MHz on the oscilator?

Paul P.
KB3LZP

Exactly.
Looking at the schematic it appears that bands 1 and 2
have fixed padders in them. For Band-2 its C-11, a 2200 mmf
cap and probably one of the postage stamps. If this has
changed value it will throw off the band. I think this is
more likely than the coil having shifted. This is a common
value so a replacement should not be hard to find. I suggest
changing it before doing anything else.




--
Richard Knoppow
Los Angeles
WB6KBL