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Hallicrafters S-38A
#1

All, I started to work on this Hallicrafters I picked up at a local Antique store. I already have a S38E so I thought I would add a S38A . Price was right because It had a broken Band selector switch..

Case is in pretty good shape..
[Image: http://i292.photobucket.com/albums/mm38/...s79ecg.jpg]


Well when opened I also found this..


[Image: http://i292.photobucket.com/albums/mm38/...05hjpm.jpg]

Burned Resistor and big black spot.. Looks like whoever wired the power cord in wired it on the wrong pins and took out the resistor.. I was able to get a band selector switch and will wire it in.. Then look at every connection to see what else might be wired wrong .. Here is bottom...

[Image: http://i292.photobucket.com/albums/mm38/...pzzhao.jpg]

Skip...
#2

 I think I have an S-38A, or a B, I also have an S-38. The S-38 has six tubes, the sixth one for the BFO, and it has an extra knob for a BFO adjustment, the A and B are similar to each other with more minor revisions. That blown resistor, was it under the 35Z5 tube? If it was then it was used as a sort of surge protector between the power line and the plate of the 35Z5. In any event there is tons of service info online for the S-38 series, at least up to the C or D model, even now they are popular sets to restore.
Regards
Arran
#3

Yup. The resistor was from Pin 2 to pin 3 of the 35Z5.. Someone hooked up one side of the AC to Pin 5 which is shorted to pin 3. Which put AC on pin 5 the plate of the 35Z5.. Anyway it blew the resistor took out the 35Z5 and who knows what else..

Skip...
#4

Ok, Recapping is underway. Also replacing the Band Switch. Looks like a lot of resistors are wayt out of spec. So will be replacing them to..

Here is a picture of the start of rewire of the 35Z5 tube.. This is where the AC was wired on wrong pin taking out the tube and the 330 Ohm resistor..

[Image: http://i292.photobucket.com/albums/mm38/...kdnmdx.jpg]

More to follow..

Skip...
#5

Ok, Capacitor Replacement coming along nicely.. Next question has anyone wired in a band switch before.. Trying to figure out best way. Should I populate the switch with wires and then solder to where they should go? or just try to use existing wires .. Problem is on the bottom contacts they are very hard to get to...

Not a lot of room to get wires to bottom..

But if I put all new wires on switch then I have to solder to some coils and do not want to maybe break the connections??


Any Clue Anyone??

Skip...
#6

Depends. The old wires maybe too short to reach the switch connection if they were cut rather than unsoldered. I would use new wire on the hard to get to contacts. When soldering to the coils I wouldn't try to unsolder the old connection, just cut it off the wire and solder the new one on. The stress and heat from trying to remove the old wire could damage the coil so cutting makes sense.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#7

Ok Sounds like a plan.. I was thinking of doing that but just wanted some input to what others might due.. Thanks Terry....

PS I broke a dial cord . And thought it would be a pain to restring one. However I got Lucky I had a box of parts from a old S-38 ?? There were 2 dial strings in the box with the springs.. So it was easy to put on..

Didn't even know I had any parts..

Skip...
#8

Ok, Parts arrived for the Electrolytic caps replacement.. Finished wiring up the Band Switch.. Mounted a terminal strip to hold the Caps. See picture..

[Image: http://i292.photobucket.com/albums/mm38/...l3toss.jpg]

Still need to replace 5 caps yet.. Then pin out the connections from the band switch .. To make sure I wired it correctly.. Then I need to order a 50L6 tube. I do not have one in stock. I have a replacement for the 35Z5 tube and the others test OK..

I do want to make this more safe so I will check the web for ideas...

If all checks out then on to power up..

Skip...
#9

So do you have breakers or fuses???[Image: http://philcoradio.com/phorum/images/smi...on_lol.gif]

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#10

Breakers.. WHY??

Good one..

Skip...
#11

Ok, All Caps and out of tolerance resistors replaced. Need to add the power cord and rewire the on-off switch so chassis is neutral and not hot.. Checked out the band switch and all appears to be correct..

Now have to double check to see if I can find a 50L6 tube in my stock..I still have the old one that reads low so will probably use it for initial checkout..

[Image: http://i292.photobucket.com/albums/mm38/...w2rigt.jpg]

This so far has been a real pain.. But determined to get it working..

Skip...
#12

Ok, Here we go again.. While checking out the Volume pot I found that the Switch was bad. So I opened it up and could not get it to work. Fortunately I had another pot and switch in the box of parts that I had for the S-38.

The old pot was 500K . The new one was 1 Meg. I subbed it anyway. Some schematics I have had the pot at 500K others had a 1 Meg and still others had a 2 Meg..

Wired in the Line cord thru the switch so the neutral is grounded and the hot side is thru the switch..

So next is on to the power up..

More to follow..

Skip...
#13

Ok, Brought voltage up on my Variac slowly. No smoke, arcs, ETC.. Got to 100 volts and radio started to play. Then up to 120 Volts drawing about .2 amps..Everything looked good and let run for 1/2 hour .. still no problems.

So on to alignment. PS it picked up AM stations just fine with NO antenna attached..So I know at lease the Broadcast band works..

So hopefully The alignment will go well. We do that tomorrow..

Skip...
#14

 Nice work Skip. Icon_thumbup
#15

Thanks Mike... Well on to Alignment. All went well. You do have to use a non metallic tool to tune the Caps..

PS the 50L6 tube that checked low on tube tester runs just fine in radio..

With a 6 foot antenna was able to receive many stations on ALL Bands. Including Band 4 the High Frequency one was able to Receive some CBers on 27Mhz. WWV at 10,15 and 20 Mhz..

So its playing very well. Installed back into cabinet.. So done with it for now.. On to the Phono that is waiting from the RCA V-210 I just recently redid or maybe start on the 46-350....

Thanks to all for help in getting this working...

Skip...




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