Author Topic: Hallicrafters S-41G Communications Receiver  (Read 5575 times)

Offline DavePEI

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Hallicrafters S-41G Communications Receiver
« on: July 26, 2015, 09:19:27 PM »
This is one of my current projects. It was another item found in the batch from Don last year.

It is a 6 tube communications receiver with coverage from 540 khz to 30 mhz. It is in rough shape, but I am rebuilding it - the case already had been straightened out, and I am awaiting 4 electrolytic capacitors for its power supply to replace a dried out multi-section cap (photo of the old multi-section cap below also - I am replacing it with individual Aluminum electrolytics of the same rating, which should fit in the same or less space as the old one). As I proceed with it, I may find other capacitors that need to be replaced.

These are transformerless radios, and the chassis is isolated from the case only by four rubber grommets. It is a good idea to install a polarized plug on them, or to run them off an isolation transformer.

The radio used 6 tubes; 2x12SQ7 for BFO/ANL/AVC/Ist audio, 12SK7 for IF amp., 12SA6 as mixer/oscillator, 35L6 audio output, and a 35Z5 rectifier.

It was made in 1935/1936, and cost $33 when new.

However, it does turn on, but with significant hum due to the bad electrolytics. Other than the bent case, died out caps, it appears to be in reasonably good shape and all tubes are good (but even if they weren't, I have replacements for them anyway), and I am looking forward to receiving the caps, replacing them, and getting it 100% operational again. Once I do, I will give it an alignment (yes, I still have my signal generators). I loved these old receivers!

Dave
« Last Edit: July 28, 2015, 10:11:00 AM by DavePEI »
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Offline Fabius

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Re: Hallicrafters S-41G Communications Receiver
« Reply #1 on: July 27, 2015, 12:46:57 PM »
Nice Skyrider Jr. Use 20 feet of copper wire as the antenna and you can hear the world. Though I am a "ham" (KD9EED) I use my Hallicrafter S-38C (5 tube) for stuffwave listening. Like your radio it has the potential of the chassis being hot. Need to use a polarized plug. Let us know how the restoration goes.
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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #2 on: July 27, 2015, 02:01:49 PM »
Hi Tom:

Oh, how I would have loved to have this when I was a kid for my SWL'ing! Instead, when I graduated from my Crystal radio, I had to use an old RCA with no BFO, and then as I got older I got my hands on an old Naval Aircraft ARB, and built a Power supply for it.

Like you, I have better receiving equipment since, but the old Hallicrafters were always fun! And like you, I also became a Ham (VE1CIT, then VY2AC) in 1983, and got my Advanced the next year. Sheesh, I am considered an old timer now. My how time flies when you are having fun!

This will make a nice receiver eventually with some new caps and a repaint. Just so people can see what these looked like on the inside and from the back, here are before stuffs of it. I am still awaiting the arrival of the new capacitors.

A Sams Photofact manual for the S41G is available on: http://elektrotanya.com/hallicrafters,_inc._s-41g_s-41w.pdf/download.html , and a good clear schematic on the BAMA Archives: http://bama.edebris.com/manuals/hallicra/s41g/

Dave
« Last Edit: July 27, 2015, 02:59:12 PM by DavePEI »
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Offline rdelius

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Re: Hallicrafters S-41G Communications Receiver
« Reply #3 on: July 27, 2015, 04:40:51 PM »
That set was also sold under the Ecophone label . I have an SX 28 in by collection have had an S15 and a S120 also.My big boatanchor is a Motorola R390A

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Re: Hallicrafters S-41G Communications Receiver
« Reply #4 on: July 27, 2015, 06:01:32 PM »
That set was also sold under the Ecophone label . I have an SX 28 in by collection have had an S15 and a S120 also.My big boatanchor is a Motorola R390A
Yes, the Echophone labelled version was the EC-1B.
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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #5 on: July 28, 2015, 09:58:41 AM »
Radio after thorough cleaning and light coat of clear lacquer on the case. As I disassembled it for lacquering, I discovered that at some point someone has had the knobs off the set, and had put the large knobs on the on-off/Volume pot and the other large one on the band-switch. These should have been on the tuning caps. They had the smaller switches with the index marking on the tuning controls. You will note they have been switched back to where they should be in this photo. Still waiting for the replacement electrolytics to come:
« Last Edit: July 28, 2015, 03:08:52 PM by DavePEI »
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Offline 19and41

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Re: Hallicrafters S-41G Communications Receiver
« Reply #6 on: July 28, 2015, 02:55:44 PM »
Hallicrafters made some great performing and affordable units.  They are fun to listen to as well.  I have a S-107 in about the same condition as this example.  I can get a lot with a 3 ft. length of stiff copper wire for an aerial.

http://www.bing.com/images/search?q=hallicrafters+s-107c&view=detailv2&&id=C7095101806B479F546940A5D6E2C8A9672F4935&selectedIndex=13&ccid=OZTv5X3t&simid=608049069188321112&thid=JN.i5azG75DXhYPg1oh%2fcbGLg&ajaxhist=0
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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #7 on: July 28, 2015, 07:33:10 PM »
Does anyone remember Sprague Kwikettes or a similar product called Queegs? They were coils of Copperweld wire impregnated with solder and flux designed to aid in replacement of components. You cut off the wire adjacent to the component close to it, clean the wire, then slip on a Kwikette. You then slip the stuffened lead of the Kwikette into the new component. A down and dirty way of connecting a new component using the old lead... I remember using them back in the 60s and 70s!

The Kwikette instructions said,

"A. Snip leads of the defective part about 3/16" from the terminal.  The remaining wire stubs should be about half the length of the Kwikette connector.  If the stubs are tarnished or dirty, scrape clean.

B. Slip Kwikette connector over stubs. Snip leads of new part to proper length and insert into Kwikette.  If the leads are fine wire, overlap end so wire inside the Kwikette connector  If leads are heavy wire, butt ends of the wire inside the Kwikette.  If the Kwikette does not now fit snugly, it may be desirable to squeeze gently with pliers to hold it in place until heat is applied."

I would love to find some of these to help re-capping my radio, but will likely wind up winding my own. Their biggest advantage was when replacing components tied to the chassis or tightly connected to tube sockets. It took far less time to connect to the existing leads than to unsolder the lead from the lug, clean it, and get a good solder joint to the old joint location.

Below the box insert, an ad from March 1966 Electronics World.
« Last Edit: July 29, 2015, 07:19:59 AM by DavePEI »
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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #8 on: July 29, 2015, 04:40:02 PM »
Update:

Ok, my caps arrived from Newark via UPS this morning.

Next problem was removing the old one and its clamp, accomplished with a Dremel. Then came trying to identify the leads of the old one, since the black and blue leads had both become black, and the two yellows and the red (different capacitances) had all faded to the same red-yellow color! Now, one would think the black (ground) would be easy to identify. Instead, it went to a tube pin used as a common ground point, and then from the pin was tied to a chassis ground point. Anyway, I have them all identified, and have stripped and marked the remaining wires the proper color using Linda's nail polish to make things simpler later. I am beat! After a break, I will mount the four new electrolytics and move on from there! Hopefully from then, I won't find any more bad caps!

This afternoon, I took the radio  out to the workshop and connected the four new capacitors with clip leads, and voila the radio works.  No hum any more. However, it lacks sensitivity and will likely need re-alignment and possible some tube replacement. Tomorrow I will mount the four new capacitors permanently, a bit of a pain, as the original capacitor had all four in one case, so I have to re-arrange things a bit. The original electrolytic was a multi-section one, no longer available, so the only option was to use 4 discrete aluminum electrolytic capacitors.

It is nice to have it working!
« Last Edit: July 29, 2015, 04:42:20 PM by DavePEI »
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Offline 19and41

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Re: Hallicrafters S-41G Communications Receiver
« Reply #9 on: July 29, 2015, 05:35:39 PM »
I guess those Kwikettes are a little before my time.  I've only been in the business since 1974.  Bet your S-41 will be fun to listen to this winter.
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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #10 on: July 29, 2015, 05:55:19 PM »
I guess those Kwikettes are a little before my time.  I've only been in the business since 1974.  Bet your S-41 will be fun to listen to this winter.
I probably won't use it too much, as I have my General Coverage Ham transceivers, but it is fun working again on tube equipment, something I haven't done much of for the past 40 years.

Kwikettes were great, especially for working on tube equipment with discrete components. Rather than trying to clean the solder and leads off the solder terminals, you could connect securely to the leads themselves. This could save a lot of time, rather than having to spend time redesigning the mounts as well. This is a major PIB when replacing a multi-section electrolytic, as you need to design a secure mounting for the individual capacitors, in this case 4 capacitors replacing one multi-section one. But it is possible - just takes more time. Thankfully, the newer capacitors are physically smaller than the old ones.

Dave
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Offline 19and41

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Re: Hallicrafters S-41G Communications Receiver
« Reply #11 on: July 29, 2015, 06:12:52 PM »
I have one of these waiting in the wings that my barber gave me.  It looks a little worse for wear.  I'll have to start on it before very long.

http://www.bing.com/images/search?q=Hallicrafters+Receivers&view=detailv2&&id=64E0FCF1023424D6C66E9EC9E55CD0A47C4A6752&selectedIndex=148&ccid=Y3Bpi5dH&simid=608012884095075987&thid=JN.8Ic5MkpIrzLCxtfIVpXrZw&ajaxhist=0
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Offline DavePEI

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Offline DavePEI

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Re: Hallicrafters S-41G Communications Receiver
« Reply #13 on: July 30, 2015, 09:27:15 AM »
Here is the Hallicrafters working on my desk. I got the caps securely installed this morning and using about 8 feet of clip-leads as an antenna, received a number of stations. I still need to re-test all the tubes, and replace any which are marginal, and work on the BFO which isn't working at present. Finally, I will touch up its alignment. Not bad for an 80 year old radio!
« Last Edit: July 30, 2015, 12:27:57 PM by DavePEI »
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Offline Fabius

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Re: Hallicrafters S-41G Communications Receiver
« Reply #14 on: July 30, 2015, 10:35:22 AM »
Here is the Hallicrafters working on my desk. I got the caps securely installed this morning and using about 8 feet of clip-leads as an antenna, received a number of stations. I still need to re-test all the tubes, and replace any which are marginal,

What tube tester do you have?
Tom Vaughn
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