Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1] 2 3 Next   Go Down
  Print  
Author Topic: Hallicrafters S-20A Restoration  (Read 24297 times)
W4OEQ
Member

Posts: 176




Ignore
« on: May 25, 2013, 04:57:16 PM »

Need the voltage and resistance readings for each of the tube sockets for the S-20A.  I am restoring the radio and need this information to assist my troubleshooting.  The brief owner's manual provides a schematic drawing but not the voltage and resistance readings ordinarily found in the service manual.  Does anyone out there have this information?  Thanks and 73, Tom, W4OEQ
Logged
AC2EU
Member

Posts: 1488


WWW

Ignore
« Reply #1 on: May 25, 2013, 05:18:47 PM »

Sometimes those old schematics are just that...schematics and if you are lucky, pin numbers and voltages.
what's the problem that you are trying to fix?
Logged

KE3WD
Member

Posts: 5688




Ignore
« Reply #2 on: May 26, 2013, 06:04:22 AM »


While Resistance Readings were often given on schematics for KITS, most notably the Heathkits, that information is not normally indicated in the greater majority of schematics and service manuals out there.  The reason is likely cost, and the fact that the competent technician does not really need that kind of data in order to troubleshoot in most cases. 

That said, the S-20 receivers are actually quite simple affairs that lend themselves well to standard troubleshooting techniques, such as basic voltage checks, AC ripple checks, signal tracing and signal injection methods, tube swapping and basic control, connections and other cleanups. 

And, they can be quite the fun receiver, as well. 

If the above listed techniques seem daunting, consider picking up some literature that shows how to diagnose and repair the old tube gear.  Some books may still be available at local libraries, also there is quite a bit of shared free info on the Internet, a Bing search is a good idea, as is finding out if there are any 'user groups' such as at Yahoo that are dedicated to the Hallicrafters stuff where you may find a guru or two that has lots of experience with your particular receiver. 

73
Logged
N4NYY
Member

Posts: 5224




Ignore
« Reply #3 on: May 26, 2013, 06:16:51 AM »

When I restored tube rigs, I replaced all the caps aside from Ceramic and Mica. I would measure then out about 10 or so resistors. If they were near or out of spec, I would go ahead and replace all the resistors in the rig.

Mostly from advice from people on this board, and personal experience, carbon composite resistors in tube rigs, have their resistance go up dramatically. Depending on which part of the circuit, it was higher than on some others.

So, I just started replacing all of them with carbon film. They are far more accurate and durable.

Once all the caps and resistors have been replaced, then it is fairly easy, as it is either a bad tube or alignment. The one thing I can tell you is, that after doing all of this, the alignment is usually dead on. However, I aligned them anyway for the experience. You may not need to.

The only other thing you have to be careful with is the speaker. My experience is that depending on storage, they are either totally fine, or crumble in your hands. The new speakers today are made with better materials, but they are a pain in the ass, because of much bigger magnets. Sometime, you have to hijack a parts unit for a speaker to physically fit.
Logged
AC5UP
Member

Posts: 4546




Ignore
« Reply #4 on: May 26, 2013, 07:06:25 AM »

As a general rule if the manufacturer didn't include voltage / resistance values on the factory squidmatic you won't find them elsewhere.  I suspect you found the user guide on BAMA, if you don't have the Rider's Perpetual sheets you should download them here: http://www.nostalgiaair.org/PagesByModel/856/M0008856.pdf  Easier to read and includes the alignment instructions for Golden Screwdriver operators like Vinnie The Tweak in New Jersey. If you had an IGGY-42 you'd do the same.

The only source that might have more detail would a SAM's Photofact - but - a quick visit to the web site will tell you the library starts at 1946.   Sad

The radio itself shouldn't be that difficult to troubleshoot especially if you're thinking refurb rather than just enough repair to make it play.  There aren't that many parts inside. Also consider referencing the tubes themselves for typical operating voltages as a ballpark for 'normal'.  See http://www.nj7p.org/Common/Tube/SQL/Tube_query.php?index=1 for more.

If learning the legend & lore of hollow state technology is of interest, go here:   http://tubebooks.org/   Very nice assortment of reference and instructional material in the technical reference section and about as close as you can get to the radio Zen of the 30's through 60's without a flux capacitor.
Logged

W9GB
Member

Posts: 3375




Ignore
« Reply #5 on: May 26, 2013, 10:01:30 AM »

Alignment & Servicing Instructions for Hallicrafters Sky Champion, S-20R
http://bama.edebris.com/download/hallicra/s20r/Hallicrafters%20S-20R%20Handbook.pdf

Restoration of Hallicrafters Sky Champion S-20R Receiver (1939-1945)
Phillip I. Nelson restoration of Antique Radio.org
http://antiqueradio.org/halli10.htm

Riders : Hallicrafters S20-R
http://www.nostalgiaair.org/Resources/893/M0008893.htm

A Well Documented (photos/narrative) Hallicrafters S-20R restoration
 by Mike Malsbary, ex-K4CWN
http://www.taowriter5000.com/RestorationS20R.html

Rod Sievers performed a miracle on saving and restoring this Hallicrafters S-20R chassis!
https://sites.google.com/site/rodsievers/my2ndhallicrafterss-20r

Hayseed Hamfest, N0IMY can supply replacement electrolytics, if desire that level of restoration.
http://www.hayseedhamfest.com/

Strategies to Repair or Replace Old Electrolytic Capacitors
by Tim Reese, Charlestown Navy Yard
Boston MA
http://www.nmr.mgh.harvard.edu/~reese/electrolytics/
« Last Edit: May 26, 2013, 10:21:50 AM by W9GB » Logged
PBPP
Member

Posts: 78




Ignore
« Reply #6 on: May 26, 2013, 04:13:01 PM »

Hallicrafters produced two (2) different S-20 receivers, the S-20 and S-20R.

They're similar, but completely different beasts.
S-20 = http://www.ohio.edu/people/postr/bapix/s20.htm
S-20R = http://www.ohio.edu/people/postr/bapix/S20R.html

~ Mitch ~
Logged
W9GB
Member

Posts: 3375




Ignore
« Reply #7 on: May 26, 2013, 11:30:39 PM »

Mitch -

Good point.  The original S-20, which ended production in 1939, is a rarer radio model.

Antique Radio Forums : Communication Receivers probably better resource for # of restorers.
http://antiqueradios.com/forums/viewforum.php?f=5

I see Tom has mirror posted his question there, as well.
http://antiqueradios.com/forums/viewtopic.php?f=5&t=223600
« Last Edit: May 26, 2013, 11:37:23 PM by W9GB » Logged
N4NYY
Member

Posts: 5224




Ignore
« Reply #8 on: May 27, 2013, 06:36:52 AM »

Mitch -

Good point.  The original S-20, which ended production in 1939, is a rarer radio model.

Antique Radio Forums : Communication Receivers probably better resource for # of restorers.
http://antiqueradios.com/forums/viewforum.php?f=5

I see Tom has mirror posted his question there, as well.
http://antiqueradios.com/forums/viewtopic.php?f=5&t=223600


They are both nice looking rigs. Do they have a BFO so you can listen to sideband? Is the 20A a typo? Love that speaker grill with the h.
Logged
AC2EU
Member

Posts: 1488


WWW

Ignore
« Reply #9 on: May 27, 2013, 10:21:45 AM »

You guys are more psyched about restoring this BA than the OP.
He hasn't been back since he requested the info!   Grin Huh Roll Eyes
Logged

W4OEQ
Member

Posts: 176




Ignore
« Reply #10 on: May 28, 2013, 07:07:55 PM »

I'm still here and still working on the Hallicrafters S-20.  I called it an S-20A out of ignorance.  Until I found this one in a box at the bottom of a storage shed, I had never heard of one.  I have replaced all of the resistors and caps and have tested the tubes (as well as can be done with an old Knight tube tester).  I have ordered replacement tubes for about half of the set.  Still have not located a voltage chart but have borrowed one from the S-40 since some of the tubes are identical, although the circuits are not identical.  Have not yet checked out all of the references you folks kindly provided.  The audio output stage is working well but cannot proceed without the replacement tubes.  As a side note, it was a lot easier task when I rebuilt an old S-38.  I will need to replace the dial screen plastic.  One is warped badly.  Any ideas on replacement material?  Many thanks for the comments and suggestions.  73, Tom, W4OEQ
Logged
N4NYY
Member

Posts: 5224




Ignore
« Reply #11 on: May 28, 2013, 07:36:35 PM »

I'm still here and still working on the Hallicrafters S-20.  I called it an S-20A out of ignorance.  Until I found this one in a box at the bottom of a storage shed, I had never heard of one.  I have replaced all of the resistors and caps and have tested the tubes (as well as can be done with an old Knight tube tester).  I have ordered replacement tubes for about half of the set.  Still have not located a voltage chart but have borrowed one from the S-40 since some of the tubes are identical, although the circuits are not identical.  Have not yet checked out all of the references you folks kindly provided.  The audio output stage is working well but cannot proceed without the replacement tubes.  As a side note, it was a lot easier task when I rebuilt an old S-38.  I will need to replace the dial screen plastic.  One is warped badly.  Any ideas on replacement material?  Many thanks for the comments and suggestions.  73, Tom, W4OEQ

I think a craft store like Michael's or AC Moore may have clear plastic. If they do, use a Dremel to cut it to fit. I use my Dremel religiously in restorations.
Logged
W4OEQ
Member

Posts: 176




Ignore
« Reply #12 on: May 28, 2013, 08:14:09 PM »

Thanks for the suggestion.  I, too, have a Dremel tool and a Michael's store is in a nearby city.  I will pursue this idea.  To clarify, my receiver seems to be an S-20R.  It looks like the photographs that I find on the web.  However, mine does not have chrome decorative horizontal strips on the left and right sides.  Tom, W4OEQ
Logged
W9GB
Member

Posts: 3375




Ignore
« Reply #13 on: May 28, 2013, 10:39:39 PM »

Quote from: W4OEQ
I will need to replace the dial screen plastic.  One is warped badly.  Any ideas on replacement material?  Many thanks for the comments and suggestions.
Replacement Dial Covers are available from many sources.

Mark Palmquist at Retro Radio Repair (Georgia)
http://jmpalm.home.mindspring.com/

Radio Daze (New York)
http://www.radiodaze.com/default.aspx

Bill Turner (St. Louis)
http://www.dialcover.com/dialcovers.html

West-Tech Services (Ohio)
Acquired the former business of Doyle Roberts, Arkansas
http://www.west-techservices.com/dial.htm
« Last Edit: May 28, 2013, 10:42:05 PM by W9GB » Logged
W4OEQ
Member

Posts: 176




Ignore
« Reply #14 on: May 29, 2013, 05:46:04 AM »

Great information!  I will follow up.  My dials are in good shape.  Just the plastic face plate is warped from too much heat in the storage facility where the radio sat for many years.  73, Tom, W4OEQ
Logged
Pages: [1] 2 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!