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

"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

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!

"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

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.

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

I have no idea how comparable they are, but I have an S-38E
which I rarely turn on. On the AM band, just south of San Francisco,
it gets about four dozen stations with only a three foot piece of wire
for an antenna. The other three bands are kinda sparse right now, but
I can hear at least a few clear stations on each.

I've had it since about 1955, I think. Nothing has ever been
replaced on it, but it has been kept in the house all that time, never
left out in the garage or other unfavorable storage condition.

In article ,
writes:

Hello Chris,I think you should examine the RF coil assy. and check for
open circuit in BC input...think about this, If this receiver had an
external antenna connected and was sitting there on the BC
band,turned off,and a lightning charge came along it would most likely
burn out the BC RF coil,making it extremely weak on that band.

This is good advice -- check that primary.
I'd like to add that many antenna primaries get blown out because someone
discovers that a ground makes a pretty good antenna -- because it's using the
hot side of the house power wiring as an antenna. If your line bypass caps are
leaky, you'll get excess AC current thrut he antenna to ground -- I've seen
sparks thrown, not big fat ones, jsut enugh to let you know it isn't good for
the coil.

And if you have a fancy antenna system with a baluyn coil, then for 60 cycle
AC, the "hot" antenna lead is as good as ground, so be sure to hook up the
ground side first. Which is just hte opposite of what PL-259 coax connectors
do ,,,
--Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.