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

On Apr 13, 6:40*pm, "Paul P" REMOVE paul @ REMOVE ppinyot .
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.

"Richard Knoppow" wrote in message
...
On Apr 13, 6:40 pm, "Paul P" REMOVE paul @ REMOVE ppinyot .
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

"Paul P" REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote in
message ...

"Richard Knoppow" wrote in
message
...
On Apr 13, 6:40 pm, "Paul P" REMOVE paul @ REMOVE ppinyot
.
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

Richard Knoppow wrote:

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.

Trying to follow your posts across the different forums.

The 38 is a plain jane AA5 with shortwave bands, Don't try to read too
much into it. Image rejection is so poor on the top band that it really
makes little difference as to how you tune it. You're welcome to try,
though.

On Apr 14, 6:38*pm, Bill M wrote:
Richard Knoppow wrote:
* * 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.

Trying to follow your posts across the different forums.

The 38 is a plain jane AA5 with shortwave bands, *Don't try to read too
much into it. *Image rejection is so poor on the top band that it really
makes little difference as to how you tune it. *You're welcome to try,
though.

I'm glad you wrote because I mistook the band Paul was trying to
align. Its band -3 which does not have a padder. So, if nothing else
seems wrong the coil may need tweeking.
I am pretty sure all the bands on the S-38 series tune with the
LO above the signal frequency. One can always try it below. If that's
wrong it won't track properly.
I don't think it has any image rejection at the upper part of
the top band:-)

Richard Knoppow
WB6KBL

The culprit: http://www.ppinyot.com/H/Hallicrafte...8straywire.JPG

The rest of the story: http://www.ppinyot.com/s-38.htm

Paul P.

"Paul P" REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote in
message ...
The culprit:
http://www.ppinyot.com/H/Hallicrafte...8straywire.JPG

The rest of the story: http://www.ppinyot.com/s-38.htm

Paul P.

Aha... This is NOT an S-38B, its an S-38. The S-38
has an adjustable BFO, none of the later versions do. No
wonder the schematics seemed wrong, they _were_.

I opened my S-38 to double check and the wire you
indicate in the photo is NOT there so this was definitely
someone's add on. It would be interesing to trace this out
and try to figure out what they thought they were doing.

I have to get at my RX soon, needs a cleaning and some
new caps.
BTW does anyone know of a source for Hallicrafters
knobs of the right vintage for this RX and the S-40 series,
etc? I've had no success at all in trying to find any.


--
Richard Knoppow
Los Angeles
WB6KBL

Richard Knoppow wrote:

BTW does anyone know of a source for Hallicrafters
knobs of the right vintage for this RX and the S-40 series,
etc? I've had no success at all in trying to find any.

Try Larry Bordonaro. I got some for my S-40A from him but that has been
several years ago.

Contact info can be found at: http://www.antiqueradioknobs.com/

"Bill M" wrote in message
...
Richard Knoppow wrote:

BTW does anyone know of a source for Hallicrafters
knobs of the right vintage for this RX and the S-40
series, etc? I've had no success at all in trying to
find any.

Try Larry Bordonaro. I got some for my S-40A from him but
that has been several years ago.

Contact info can be found at:
http://www.antiqueradioknobs.com/

Thanks, I'll try him.


--
Richard Knoppow
Los Angeles
WB6KBL