Super Sonomatic; "SUPER" project!

[Drakeule]

I just acquired a 1941 Super Sonomatic (980660) that is in need of a complete overhall. The bandswitch is completely frozen, which necessitates removal of the bottom half from the top.

Does anyone out there have any experience with this model?

 

Specifically,  what moves in that lower half to switch bands? Also, the clutch for the push buttons energizes when I turn it on; what do I need to do to get it to return to manual tuning?

 

I will post some pictures later on.

 

Thanks in advance,

 

Charlie Drake, Potomac, Md.

[Kenneth Carr]

I have only worked on the single band version (local AM broadcast, not shortwave). There are some similarities. If the band switch does not move, I recommend treating it with PB Blaster. Do this repeatedly at all friction points. If there are ball bearings along the shaft, target that area too. Each time you apply the blaster, rock the switch slightly. Then let it sit for about an hour. Then repeat.  Eventually you may get more movement until finally it breaks free. Stuck switches are usually due to dried up grease. 

Clean the linkage attached to each push button. They are likely sticking, again due to dirt and grease. Carefully pull each button back towards you rather than pushing in. They should eventually give. Be careful because they tend to crumble due to the poor plastic used. You can also remove them if you like. Some people will apply heat to friction points of a stuck shaft. They use a high temperature soldering iron. This is dangerous since you may damage something such as a wire, plastic, etc. A circuit diagram and some other information is available at Nostalgia Air: Buick Motor: 980660 (nostalgiaair.org) .  The following tells how to set up the pushbuttons for particular station recall. The "remove button" instructions may help you get them off.

Pushbutton removal: "5 buttons: Remove button by pulling spring located on bottom of button, to the right. Loosen set screw. Tune in desired station by using manual control. Push screw in as far as possible and tighten. Replace button. Follow same procedure for remaining buttons."

[Drakeule]

Okay, all....against my better judgement, I have decided to somewhat document my restoration of the Super Sonomatic. Initially, I determinted that to assess the fairly complicated push button/manual tuning mechanism,

I had to remove the top section from the lower half, which contains the push button cage.  Picture SS1 is upper (the one with all those toasted capacitors!); SS 2 is the lower (with the push button cage.)

 

I had to unsolder/cut about 20 wires to do the above, carefully tagging each one.....

 

Of course, on the standard BC band radio (980650), the tuning is fairly simple: just turn the right hand knob, or use the pre set push buttons (which you've previously set to select stations.)However, with the SS, the right hand escutcheon knob tunes you to one of 5 bands (standard BC and 4 SW bands.) This is indicated  by the small plastic scroll ,which has the different bands etched on the plastic film (as seen in SS 2 and SS 5.)

 

I can't believe that I was actually able to separate the silk screened film from the plastic scroll, by using blasts of compressed air and a dental pick; the film came off with some damage, but basically intact! From there, I was able to clean the film using a q tip and some windex. Granted ,I did end up rubbing some of the  numbers off slightly.However, it's mostly intact, and much clearer.

 

The scroll is spring loaded and when the string pulls it to indicate the different bands, it has a spring under tension which rolls the scroll back to the band that it's presently on.

Sounds a little complicated, doesn't it? Hope I can get this thing to work after so much time..

 

Now for reassembling the lower half. As I  progress, I'll detail more and include pictures. Hopefully, it will become clearer as I go along.

 

P.S.Oh, I hope I can get this thing back together and get it working...

[EmTee]

I'll be watching this thread with interest, as I'm planning to tackle refurbishment of the radio for my '38 as a winter project.  You should be able to take the label that you removed from the scroll to a local graphics/sign shop.  They should be able to scan the original film, touch-up the graphics digitally, and print a replacement.

[Frank DuVal]

Quite a few radio restorers are surprised to find some dials are made with water based ink...🙁

 

While most radio people would say to replace all the wax/paper capacitors while you are in there, I will say you really really want to replace the vibrator buffer capacitor NOW.

[Drakeule]

Today, I tackled the dial assembly, including the infamous right hand escutcheon switch which moves through the bands. A really frustrating and complicated affair.That cylinder sits spring loaded in the upper chrome assembly, SS 7 shows the wheel with string that turns the cylinder, and SS 8 is the back view. Think a wind up toy that requires a lot of cranking before it works: the cylinder is on a shaft and you need to crank it several times to get enough tension so that the right band will snap back and show correctly in the window. A couple of Q tips held the cylinder against the inside of the chrome box, so that I could bring the cord down past the  pulley and screw it to the main wheel, visible in  SS 7.       

SS 6 below shows the whole thing back together

[EmTee]

Looks like lots of old, crusty grease on that band select switch assembly...

[Drakeule]

Pretty much finished up the lower half of the radio today.Getting the dial indicator to work smoothly was more of a challenge than I thought; I think that besides getting new dial cord, it's pretty much done. I presently have

some heavy carpet thread doing duty; however, dial cord is readily available (and much more durable!)

 

SS 9 shows the cap that shoots off parallel with the 6V power cord(.5 uf/600 WVDC.) I replaced it shortly after taking this picture.You see these spark arrestors all over before car radions, as everything in the car (e.g., crankshaft, generator, ,etc.) evidently produces RF. These caps will short that stray voltage to ground. The above is also why yopu see so much shielding around the tubes and other components in general.

 

SS 10 shows the next step of the project: recapping the radio by replacing all the unravelling tubular paper caps"Christmas crackers" (that's what they remind me of anyways!)

[Drakeule]

I don't know why but the pictures in the last post reversed themselves, SS 9 is the lower one (sorry for any confusion.)

[Frank DuVal]

Christmas Crackers!🤣  Great description!

[Eddie-O]

I had a similar problem with my super Sonomatic a year or so back with the band selector. Would turn on and buzz but the selector was frozen. Just a word of caution. My radio was in mint condition as far as appearance went. Have yet to find one for sale that looked as good so I decided to send it out to be repaired. After searching for someone who could repair the unit I sent it out to a supposedly radio repair specialist. I won’t mention his name except that it was one of the biggest mistakes I ever made. After waiting for months almost a year and endless excuses I had him return the radio. To shorten the story, it was destroyed! There are very few people who can service a Supersonomatic correctly. They are a special breed. I did find a first class repair tech in PA but to soon to late. His turn around time was a year plus because he’s swamped with work. There was nothing he could do to fix mine since the other so called tech had butchered mine up beyond repair. People who update post war radios are a dime a dozen, but Supersonomatics are more than just a radio. I guess what I’m saying is if you don’t know them inside and out, find someone who does and save yourself a world of grief and money. I now have a delete plate where mine was and am still looking for a replacement. Good luck and take the advise from someone who got burned real bad. Avoid the hit and miss advise on forums on how to fix it. The professional repair techs are few and becoming fewer every year.

[Drakeule]

All:

 

Eddie-O's above comment points out exactly why I am doing it myself. These guys want a king's ransom to repair your old radio.

 

BTW, my first degree was in electronics engineering technology (albeit that was 40 years ago!); and I am a member of the National Capital Radio and TV museum. I have taken their radio repair class twice, and have some real horsepower in the form of several, genuine radio repair engineers at the museum's workshop.In fact, I have been able to raid their cache of parts at will; giving back donations to the museum. Dick Maio (my former instructor and friend) and the other instructor, Oscar Leary are, without being too dramatic about it,  my "touchstone" guys.They will also, for a fee, repair your radio. The most competant fellows I have run into concerning radio repair.

 

In fact, if anyone lives within shouting distance of the museum (Bowie, Md.), I suggest you visit; a fascinating place to learn about the history of radio and television. 

[Drakeule]

Well, I am finished with soldering the various value caps into the upper half; a very tedious process! (SS 11.) SS 12 shows how I kept track of everything! SS13 shows where the combo of buffer caps and resistors goes; there is actually a "coffin" which covers that area.The outline is faintly visible. This provides even more sheiding against RF interference. Mine is missing, so it was suggested that I make one from brass screen and use copper tape which will be soldered to the edges, thus making it truly electrically sheilded. I am attempting to locate the buffer caps,but will just fabricate from ones I have if I can't. SS 14 shows the tube which houses three 20 uf capacitors. Many guys "restuff" these with modern electrolytic caps,so as to make it look more original (a lot on that on you tube.) I am going to attempt that myself. After these two tasks are done, I just need to get some correct dial cord before reassembling the entire radio (i.e., resoldering and splicing the 17 or so wires back to their original positions.

[Eddie-O]

Drakeule

Looks like you might have a real handle on that repair. With your background and that of your friends I’d say that radio stands a very good chance of coming back to life. I know absolutely nothing about radio electronics that’s why I had sent mine out to be repaired. Again, “ Big Mistake” on choice of techs. Partly my fault for not doing my homework better on repairman even though he assured me he could fix it and partly trusting forum comments. Like I said, and I’m sure you know by now the Supersonomatic is a special breed. The one person I finally found who new those radios inside and out was at Hershey. I can’t remember his name but you can google him up. Lived in PA. Older chap but a SS wizard. And talk about shooting myself in the foot twice, I had sent mine all the way to the west coast and he’s about five hour drive from home. Ugh! So busy though you can’t be in a hurry to get it back. Year and a half or longer. Every time I look at that delete plate I want to scream! About two years now and still trying to find a nice looking SS working or not. The 41’s are hard too find in decent shape today since the cowl vent above it allowed water down onto them. Most are rusted junk now. Hence a premium price working or not for a nice one like I had. Blood pressure is rising now just talking about this so I need too go and take a pill! Good luck and I hope it all works out for you.

[Frank DuVal]

Wonderful you are taking advantage of the NCR&TV Museum. I am a member also, but a little too far away to go there often. I'm also a member of MAARC (Mid Atlantic Antique Radio Club) which is a partner of NCR&TV Museum.

 

https://ncrtv.org/

[Drakeule]

Frank:

 

MAARC-me too! Hope you get a chance to come up to one of the Sunday meetings (next S; 16 July); IMO, just as good as Radioactivity.

[Drakeule]

All (below is also posted under buy/sell thread.):

 

I have hit a snag in my "resusitation" of the Super Sonomatic (980660). By what I can determine, the primary of the transformer is shorted to ground somewhere. I'm pretty sure it's in the transformer itself,so I need to find another from a Sonomatic (and hope that it's not shorted too!)

 

Anybody have one that they are willing to part with?

 

Thanks,

CD

[Bloo]

Have you got the primary out of circuit to check for sure?

[Drakeule]

Bloo:

Well, the vibrator is not in,and I still get a short with either primary lead to ground. the 2 primaries of the transformer are now just going to blank sockets, so, yes. I guess I could disconnect the primaries just to be sure.

 

BTW, the resistance across the primary is .1 ohm (or less); resistance across the secondary is

about 595 ohms.

 

I think that the transformer internal cap might be shorted; it's a .05 uf cap.

[Gary_Ash]

Will the transformer from the AM-only Sonomatic work?  It had two fewer tubes but otherwise related circuitry, maybe same transformer.  There is one on Ebay for $38.95.

[EmTee]

There are companies that rebuild/rewind transformers.  I can't recommend one, as I haven't personally had to have one rebuilt (yet).  One such company that seems to have positive reviews online is Mercury Magnetics: https://www.mercurymagnetics.com/brands/mercury-vintage-transformer-restoration-service/ .

[Bloo]

On 7/9/2023 at 12:12 PM, Drakeule said:

 

I think that the transformer internal cap might be shorted; it's a .05 uf cap.

I was looking at that. It appeared on the schematic that they potted it and the choke in the transformer. Insane if so was my first reaction, as any .05 high voltage capacitor from 1941 is paper, and shot, and another transformer even if working isn't going to be better for long. On further thought, that is the hash filter, and being a multiband high performance radio, they probably put it in there to shield it and keep the electrical and radio noise under control. Hmm. I think you'll have to melt it apart no matter what. That capacitor has to go and I don't see any way to isolate it. Hopefully the choke and transformer are good. It only hurts for a couple hours, and you'll only stink for a day or two. Potting material "wax" is probably some kind of tar, and probably has some rosin in it so I suspect it is going to snap and pop. You may not need to re-pot it, you probably won't, but I would make an effort to save the goo that melts out just in case. Whatever it is, you probably can't just buy more. I imagine there are some threads over on the Antique Radio Forums about un-potting transformers. I don't have much to say about the process because I haven't done it in the last 30 years.

 

Edcor is another company who will custom make a transmformer. They don't rewind, but unwind the old one and make an exact copy on new laminations. This may be less costly than a rewind. You would still need to melt the old one out and put the new one in I think.

 

[Steve_bigD]

Look for threads on Atwater Kent radios on Antique Radio Forums since they had a habit of potting the whole power supply including the transformer, capacitors and chokes. Here is one I found:

 

https://antiqueradios.com/forums/viewtopic.php?f=6&t=401263&hilit=atwater+kent+potting+removal

 

Steve D

[Drakeule]

Unhooked the transformer and the primary is .1-.2 ohms.; so it may not be the Transformer. Finally, I got back to some output on the B+ voltage (about half of what the radio needs: 120 vs 265 V.)

 

What I have found is that whatever source I provide for the radio (car battery or bench power source), 6Vs suddenly reduces to about 4.2 Vs. I get this with the vibrator out of the radio as well. So, there must be a big internal resistance in the vibrator that is sucking the voltage down.

 

I've cleaned the contacts multiple times, and used the AC with a light bulb in series trick, but it doesn't change the suck down siginificantly. Probably just a worn out mechanical vibrator. I am on track to get another mechanical one, but that too will be a shot in the dark. Most likely a  PEKO SS unit might be where I am heading; problem here is I have heard that these aren't very robust,and I could burn it out (as the radio still has problems.)

 

I've burned two out before, so, I'll keep my fingers (very) crossed!

[EmTee]

6 hours ago, Drakeule said:

Finally, I got back to some output on the B+ voltage (about half of what the radio needs: 120 vs 265 V.)

As if you're looking at half vs. full-wave rectifier output?

[Drakeule]

B+ is DC. I'm pretty sure that the rectified wave shouldn't get greater in voltage just because it's been rectified. However, I'll investigate. Time to break out the O scope!

 

Thanks,

CD

[Kenneth Carr]

The vibrator on the 1941 Buick is of the synchronous type. It has one set of contacts that chop the DC to simulate AC and thus activate the step up transformer to create high voltage B+. It has a second set of contacts that act as the rectifier, thus eliminating the need for a rectifier tube. See discussion here: http://www.nostalgiaair.org/Forums/t1581.htm

I was able to get the proper high value buffer capacitors from justradios.com . He is a reputable dealer who sells quality capacitors and resistors.

Here is one method that sometimes restores a vibrator by burning off residue from old foam: http://www.skywaves.ar88.net/commrx/Maintenance/Waking Up.doc.pdf

Another method uses diamond files to renew the contacts.

There is also a video on You-Tube that shows how to repair a vibrator. If I find the link I will post it here.

 

[Kenneth Carr]

Restoration of a vibrator: 

 

[Drakeule]

Ken:

Thanks, but I have used the AC trick and, as I said, I still get a voltage drop when I connect the vibrator to the car battery.

 

And yes, I have watched the stentorian voiced guy's video that you attached. I even have a vibrator tester plug in for my tube tester; but it's only for 2 or 3 pin types, not 5 pin ones!

 

Like I said before, my understanding is that some vibrator's contacts just get worn out,and there's nothing you can do about it. I think that's what I have here.

I did order a burnishing tool on line, and am going to try that on the contacts, but I don't hold out much hope. Another mechanical vibrator (or a SS mock up) might be the way to go.

 

Thanks,

CD

[EmTee]

14 minutes ago, Drakeule said:

And yes, I have watched the stentorian voiced guy's video that you attached.

I learned another new word today -- thanks! 

[Drakeule]

Some significant progress here, albeit slowly.

 

Today, Oscar Leary (instructor at the NCRTVM) and I worked further on the SS.After replacing a few other capacitors, we teased out and confirmed that the final audio stage was working, then injected a modulated signal through the 2 intermediate frequency (IF stages), confirming that they indeed were doing their jobs. Working back, we encountered a few problems at the oscillator stage,which is working ,but intermittantly. This took about 3 hours!

 

So, what does all this mean? Without going through the theory that explains how a heterodyne radio functions , you move backwards through all the stages of a receiver from where the sound comes out, to the place where the radio waves come in (i.e., antenna), to find out where your problem(s) are.

 

Back at it on Friday; more then.

[drhach]

Have you checked your turb encabulator?

 

 

 

 

 

Edited August 2, 2023 by drhach (see edit history)

[EmTee]

[drhach]

All of the radio terminology made me think of that video. My Father in-law is an electrical engineer from the 50's-60's I was commenting about my concern with the radio in my 1942 and how I would need to align it and generally sort it out. He said, "it's just an old Heterodyne radio, what's the big deal?" I get mechanical things. But radio stuff is like voodoo to me. 

[EmTee]

Ha, I understood why you posted that video.  I wonder how many takes it took for that guy to get through the whole schpeel without laughing out loud.  My guess is it was either done in one take, or it took more than 30... 

[Drakeule]

All:

 

A pause here; my understanding is that, due to the War, Buick (upon instruction from the Government) "asked" all owners of cars with Super Sonomatics to bring in their cars and that they would swap out the SS radio for regular Sonomatics.

 

Now, I wonder what happened to all those SS radios sitting on the shelves of said dealers? Many religated to the scrap heap?

 

When I get this radio sorted, I might make a trip to the AACA Archives to do some detective work!

[EmTee]

2 hours ago, Drakeule said:

Now, I wonder what happened to all those SS radios sitting on the shelves of said dealers?

[Drakeule]

Prolly!

[Frank DuVal]

Are you all aware of the US government asking radio repairmen to disable the shortwave bands of radios owned by European nationals/immigrants during WWII?

 

https://www.antiqueradios.com/forums/viewtopic.php?f=1&t=84205

[Kenneth Carr]

6 hours ago, Frank DuVal said:

Are you all aware of the US government asking radio repairmen to disable the shortwave bands of radios owned by European nationals/immigrants during WWII?

 

https://www.antiqueradios.com/forums/viewtopic.php?f=1&t=84205

They did this to my grandfather’s Zenith console. The shortwave bands were disabled. Nobody ever returned to fix the radio after the war. This was done because he was born in Italy. My grandfather, Andrea Calise, earned his US citizenship in early 1941 when he took his test in front of a local judge. Upon approaching the judge he told him that he had left his glasses at home and so could not read the test. The judge read the test to him and grandpa passed. Glasses were not the issue,my grandfather could not read or write. After coming to this country he eventually brought over his mother and his 10 brothers and sisters. There was a temporary home and a job waiting for each. And during the war his future son-in-law, my dad, served in Paton’s army. Hopefully we never treat our citizens this way again. The photos show gramps (original and colorized) and my parents.

Edited August 4, 2023 by Kenneth Carr (see edit history)