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Old March 1st 04, 05:35 AM
Chris Kilmer
 
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Default Hallicrafters s-38C question

Hey folks, got a question: I just bought a S-38C and have replaced
most of the resistors. I will be replacing the rest of the capacitors
this week. I've also replaced all 5 tubes with new ones from AES. The
radio does work a lot better than it did when I first got it, but two
problems remain:

1) I only pick up 3 local AM stations (I live in downtown Washington,
DC.) Is this something I should be concerned about? I am new to all of
this, and I am still learning... but it seems to me that this radio
should be picking up more than 3 stations. I have a pretty big antenna
attached to it, so I'm pretty sure that's not the problem. Is living
smack-dab in the middle of downtown the reason why I can't pick up any
AM stations besides the local megawatt monsters? Or might the poor
reception be due to the fact that there are still 5 wax capacitors
that haven't been replaced? Bands 2 and 3 pull in tons of stations;
band 4 only pulls in a few but I'm not worried about that.

2) When I first got the radio, it worked but not very well. The
bandspread tuner worked fine, but after I operated it for a few hours
and then turned it off and started ripping out caps and resistors for
replacement, the bandspread didn't work the way it used to. Now, it
tunes just fine from 0 - 70, but when you turn it past 70 a very loud
crackle is heard, and then there's nothing but a soft buzz. If you
turn the knob back down below 70, the stations come back. Besides this
problem, the bandspread tuner works like a champ.

I've been having a great time restoring this thing, and learning from
my mistakes. I've got a shipment of the remaining capacitors that I
couldn't find at AES coming to me this week from Mouser... when I'm
done replacing those, there won't be much left to replace!

Thanks.
chris
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Old March 1st 04, 06:47 AM
Phil Nelson
 
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"Chris Kilmer" wrote in message
om...
Or might the poor
reception be due to the fact that there are still 5 wax capacitors
that haven't been replaced?


Yes. You should also carefully clean the bandswitch, along with other
controls such as volume, etc.. Corroded/gunky contacts on the bandswitch are
an almost-universal problem in multi-band radios that have been sitting
around for a long time. DeOxit spray cleaner is a favorite among restorers.
You can also use spray tuner cleaner from Radio Shack, etc.

Phil Nelson
http://antiqueradio.org/index.html


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Old March 1st 04, 06:49 AM
Temporary Flatlander
 
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I think (uh oh) #1 could be due to the caps or front end
desense/overload.

#2 - Did you check the tuning cap on the bandspread to see if any
vanes were shorted or bent?

I have the S-38B, just guessing.

On 29 Feb 2004 21:35:09 -0800, (Chris Kilmer) wrote:

Hey folks, got a question: I just bought a S-38C and have replaced
most of the resistors. I will be replacing the rest of the capacitors
this week. I've also replaced all 5 tubes with new ones from AES. The
radio does work a lot better than it did when I first got it, but two
problems remain:

1) I only pick up 3 local AM stations (I live in downtown Washington,
DC.) Is this something I should be concerned about? I am new to all of
this, and I am still learning... but it seems to me that this radio
should be picking up more than 3 stations. I have a pretty big antenna
attached to it, so I'm pretty sure that's not the problem. Is living
smack-dab in the middle of downtown the reason why I can't pick up any
AM stations besides the local megawatt monsters? Or might the poor
reception be due to the fact that there are still 5 wax capacitors
that haven't been replaced? Bands 2 and 3 pull in tons of stations;
band 4 only pulls in a few but I'm not worried about that.

2) When I first got the radio, it worked but not very well. The
bandspread tuner worked fine, but after I operated it for a few hours
and then turned it off and started ripping out caps and resistors for
replacement, the bandspread didn't work the way it used to. Now, it
tunes just fine from 0 - 70, but when you turn it past 70 a very loud
crackle is heard, and then there's nothing but a soft buzz. If you
turn the knob back down below 70, the stations come back. Besides this
problem, the bandspread tuner works like a champ.

I've been having a great time restoring this thing, and learning from
my mistakes. I've got a shipment of the remaining capacitors that I
couldn't find at AES coming to me this week from Mouser... when I'm
done replacing those, there won't be much left to replace!

Thanks.
chris


Use the usual techniques to reply via email.

Molon Labe!
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Old March 1st 04, 03:18 PM
Frank Dresser
 
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"Chris Kilmer" wrote in message
om...
Hey folks, got a question: I just bought a S-38C and have replaced
most of the resistors. I will be replacing the rest of the capacitors
this week. I've also replaced all 5 tubes with new ones from AES. The
radio does work a lot better than it did when I first got it, but two
problems remain:

1) I only pick up 3 local AM stations (I live in downtown Washington,
DC.) Is this something I should be concerned about? I am new to all of
this, and I am still learning... but it seems to me that this radio
should be picking up more than 3 stations. I have a pretty big antenna
attached to it, so I'm pretty sure that's not the problem. Is living
smack-dab in the middle of downtown the reason why I can't pick up any
AM stations besides the local megawatt monsters?



I don't think so. You should hear dozens of AM broadcast stations.


Or might the poor
reception be due to the fact that there are still 5 wax capacitors
that haven't been replaced? Bands 2 and 3 pull in tons of stations;
band 4 only pulls in a few but I'm not worried about that.



Yeah, don't jump to any conclusions until you've replaced the
capacitors. And be sure the alignment is correct. The RF aligmnent can
be way off on the top three bands and the radio will still recieve
stations because these bands have little RF selectivity. The alignement
on the AM broadcast band is more critical.



2) When I first got the radio, it worked but not very well. The
bandspread tuner worked fine, but after I operated it for a few hours
and then turned it off and started ripping out caps and resistors for
replacement, the bandspread didn't work the way it used to. Now, it
tunes just fine from 0 - 70, but when you turn it past 70 a very loud
crackle is heard, and then there's nothing but a soft buzz. If you
turn the knob back down below 70, the stations come back. Besides this
problem, the bandspread tuner works like a champ.


One, or both, of the plates on your bandspread capacitor is bent. These
plates are very vunerable due to their length and position. You might
be able to spot the bent plate by carefully eyeballing each plate as it
rotates into it's closed position. If it goes off center between the
fixed plates, it's probably touching the fixed plates. A bit of gentle
bending will put it right.

It's best to close up the band spread cap whenever servicing the radio.
Especially when replacing the 12SA7!


I've been having a great time restoring this thing, and learning from
my mistakes. I've got a shipment of the remaining capacitors that I
couldn't find at AES coming to me this week from Mouser... when I'm
done replacing those, there won't be much left to replace!

Thanks.
chris


If you need any alignment tips, fell free to ask. You can do a good job
on this radio without a signal generator!

Frank Dresser




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Old March 1st 04, 05:09 PM
Mike Knudsen
 
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Default

In article ,
(Chris Kilmer) writes:

) I only pick up 3 local AM stations (I live in downtown Washington,
DC.) Is this something I should be concerned about? I am new to all of
this, and I am still learning... but it seems to me that this radio
should be picking up more than 3 stations. I have a pretty big antenna
attached to it, so I'm pretty sure that's not the problem. Is living
smack-dab in the middle of downtown the reason why I can't pick up any
AM stations besides the local megawatt monsters? Or might the poor
reception be due to the fact that there are still 5 wax capacitors
that haven't been replaced? Bands 2 and 3 pull in tons of stations;
band 4 only pulls in a few but I'm not worried about that.


It's typical that Bands 2 & 3 will pick up plenty on a simple radio, and
typical that Band 4, which is usable only during daylight hours, will be weak
on a 4-tube radio without an RF amp stage.

But the fact that Bands 2 & 3 are so alive, points out that what ever's wrong
with the AM BC band 1 is peculiar to that band, and not the radio as a whole,
that is, not the remaining wax caps (which you still want to replace anyhow).
AM BC is an easy band for even the simplest radio to receive well. My guess is
alignment, or dirty bandswitch contacts (spray them with Deox-It, don't waste
your time with Rat Shack tuner cleaner). Good luck, Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.
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Old March 3rd 04, 08:48 PM
Ed Zeranski
 
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....... My guess is alignment, or dirty bandswitch contacts (spray them with
Deox-It, don't waste your time with Rat Shack tuner cleaner).
Good luck, Mike K.


I just reworked an S-38C for a co-worker. Along with the dirty switch
contacts several of the grounds to the chassis had corroded and needed to be
cleaned up. The wipers on the tuning caps needed attention too. My shop
antenna is a 35ft wire at the apex of the garage roof. With that hooked up
the little guy does great on shortwave broadcast, 75mtr AM etc. With no
antenna it gets all the local stations.

EdZ
San Diego


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Old March 3rd 04, 11:35 PM
Bill Turner
 
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Default

THERE HAS TO BE SOMETHING WRONG WITH THE FELLOWS SET THAT HE SAYS IS
"JUST A AA5". I WISH ALL THE AA5 WERE AS GOOD AS MY S-38-A-B-C-D-E AND
SR-75. SOME OF THEM TOOK A LITTLE WORK BUT THEY COULD HARDLY BE
CONSIDERED AS ORDINARY.


CHECK MY WEBSITE: www.dialcover.com
Bill Turner, excuse caps, short answers, stroke.
Business SASE, each order a copy of The Pocket Resource Guide.




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Old March 4th 04, 05:34 PM
Dbowey
 
Posts: n/a
Default


THERE HAS TO BE SOMETHING WRONG WITH THE FELLOWS SET THAT HE SAYS IS
"JUST A AA5". I WISH ALL THE AA5 WERE AS GOOD AS MY S-38-A-B-C-D- BRBR

Look around the flat thing plugged into the computer thingy with all the
buttons, for one called "caps lock," and push it once.

Practice with it and see how it works.

Don


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