Say it isn't so!

This is a follow-up to the chassis restorations presented below:
​https://www.russoldradios.com/blog/back-on-the-farm-radio-again-zenith-5-f-134

In that post we discussed differences in the 5516 chassis - and replated a couple of them.

Obviously, each cabinet is different and this chassis was placed into 6 different models. Production changes are expected and were not particular to Zenith.  Philco was notorious for dozens of changes in some 1930's models as were many smaller manufactures.

​What is unusual are the undocumented changes to this chassis in that the published schematic represents a version that had a significant flaw and most radios found do not comply.

Pictured above is the 5-S-127 chassis that I replated and restored in the previously mentioned post. This layout is what is typically found.

But , take a look at the schematic. Many restorers have come to this point and then spent days trying to figure out why their radio is significantly different. And it appears that the largest fraction of chassis produced DO NOT conform to this schematic or parts list, BUT their radio seems to work fine.

What is worse is that if you try to follow this schematic the result is a radio that works - poorly.

Most noticeable is the difference in the field coil impedance, most as-found with 1000 ohm field coils. In these radios the power transformer is significantly larger. In the second picture (from the top) you can see both the size difference in the PTs and different speakers.

The "spec" field coil is 2125 ohms (or 2150).

When you dig deeper a person finds that R5 and R10 are way off from spec - not that they drifted, it was built that way! R10 is most often 490k ohms rather than 990k ohms and R5 is 240k ohms rather than 190k ohms.

I have heard it said that these differences were to accommodate the different field coil values and that is probably true since you would need to change these parts to accommodate the larger field coil impedance. 

​Well, then why doesn't it work? Or,  why does the radio with the 1k ohm F.C. work so well with the wrong resistor values?

I should note at this point that there are several other differences, like band switches that are different enough to require different knobs in order to point to "A", "B" and "C" and a lot of minor stuff.

Above, as found - as most are found not conforming to the parts list. This radio would have (does have) a speaker with 1K ohm F.C.

Above, conforms to the schematic, has a 2150 field coil and works poorly.

So what is the deal?

Most people speculate that parts availability explains the need to "redesign" the radio in mid production, but here is the problem:
​
A radio with the 2125K F.C. and the non-spec resistors (R10 240K, R5 490K) will have about 285V on the 6F6G plate and -37V bias on the grid. This is almost twice the allowable bias according to the RCA tube manual which shows -20V on the grid.

A radio with the 2125 F.C. and the resistors on the schematic (R10 190K, R5 990K) will have 167V on the 6F6G plate and -27V on pin 5, the grid. This is better but the audio is still limited and settings in the upper third of the vol. cont. range are distorted.

A radio with the 2125 F.C. and the resistors on the schematic (R10 190K, R5 990K) and the 1.5K ohm resistor placed in parallel with the F.C. will have 255V on the 6F6G plate, 265V on the screen and -21V  on the Grid. The radio will work normally and the volume is good through the range.

A  radio built with the " non-spec" resistors (R10 240K, R5 490k)) but with a 1000 ohm F.C. (49-165) will work just fine as-is..

Note that:
Higher line voltages today will also raise these voltages somewhat. 
The speaker F.C., though in the return leg, was designed to avoid the typical candohm used to generate a negative bias voltage and provide some ripple filtering on the B+..
A resistor in parallel with the F.C. does not offer the same inductance so some hum might appear, though this was not the case on mine.
I checked both 5-S-119 and 5-S-126 radios on display in the museum and they were the 1000 ohm F.C. variety.
I checked as many radio pictures  as I could find on-line and they were consistent though I don't know their history and a lot of pictured radios had owners/restorers that I referred to earlier (WTH is going on here???) so my first hand observations of original and mostly original radios is the basis of my conclusions. Input is invited.
B+ on the detector was also high. Spec. is 75V and it was as high as 150V in some configurations. B+ was high everywhere do to the decreased load presented by the 2125 ohm F.C.
​

There would be better ways to "fix" this problem but most would result in several visible changes to the layout. What I chose to do was use the parts as speced in the schematic and add a 1.5k ohm 3W resistor in parallel to the 1K field coil. This increases the current draw on the B+ by 20ma and does not seem to cause a noticeable temperature rise in the stock (smaller) P.T.. I partially offset the total draw on the P.T. by using LED lamps for dial lights. (small light green WW resistor above)

Above is my 5-S-151 console who's chassis is described by this schematic. It calls out another 2125 F.C. speaker, 49-144, a 10 inch model.

This is the speaker that is actually in the console - a 1000 ohm unit, (49-118AB).  I have never seen a console with the 2125 ohm field coil speaker, (49-144). I do not know if they exist.

So what percentage of chassis/speaker combinations are compliant with the schematic - I do not know. At this time, I have the one pictured. From my files I found one that was sold about 10 years ago to a local fellow that used it at night to drown the high pitched whine caused by tinnitus. I don't recall much more about that unit though it was a "looker" (cabinets really do vary a lot). If he was to read this post, I would like to do a check-up on that radio too.

In conclusion, for what ever reason, Zenith built quite a few of these chassis/speaker combinations that worked poorly. The change was probably to correct this error. The power transformer change was probably called for by a slightly increased B+ load. The error is well documented. It would make sense that the error was in early production. In mine it appears on the plated chassis rather than the painted chassis though I am not certain if this is always true.

​See also: https://www.antiqueradios.com/forums/viewtopic.php?f=1&t=401068

Has anyone ever seen a schematic with the proper parts?

Russ

P.S. I want to tell you about the lighter colored 5-S-127 cabinet with the replated chassis. I really like those veneer choices. So many of them are really dark.

And what is it with the 1937 Zenith band switch drawings - in particular the antenna switch section on the multiband radios? It seems to be in an impossible position. Those connections - the one connection alone - never occurs in any of the switched positions - maybe in radios with an X-band, but still that would have been specified. Best I can tell it was drawn with the contact rotating from the wrong direction BUT this is not the only contact on the wafer, those are correct.

AND have you checked a 6A8 on your Hickok tester lately. I found the settings on my roll chart ARE WRONG, particularly for the bias which is 30-something on the chart but only 11 on the trusted Consolidated Test Data For Hickok Model 533A-600A-605A Tube Testers. No wonder I've seen so many sales of "low testing" tubes.

​I am still looking for 5516 chassis to further study (any variety) and complete projects. I also need period correct Zenith tubes. Thanks to all who have helped.

IN a previous post I mentioned that one of my favorite Zeniths is the 1937 5-S-127. It was far from top-of-the-line, in fact,, closer to the bottom. I suppose that the real attraction is the cabinet design, though the radio is not bad for only having 5 tubes.

The Crosley 6H2 is probably my favorite Crosley. Like the Zenith, it is the cabinet design with a not-too-bad radio that appeals to me. And, like the zenith, it seemed to have been popular at the time of sale. Far from the WLW (or stratosphere), it has good performance in a 6-tube chassis.

There is some confusion over the number of this model. Instead of giving it a name, like Buddy Boy, Crosley used a model number. 6H2 was assigned to the chassis and this is usually the "Model" on the tag, though there are certainly variations of this chassis. In some cases the model is called the 61 which seems to refer to the radio/cabinet configuration. Confusion is amplified by the question of model-year. I call the radio above a 1934 model, but there were likely to have been versions of this radio sold several years later

I did replace the broken pointer after this picture was taken..

So, the real mystery, for me, is  - Why did they change this popular cabinet during its production run?

I have always wondered why Crosley slapped the hardwood panel over the top of the scroll work.. Possibly more to the point, why did they do the scroll work in the first place? It was not a common feature of radio cabinets at the time. It would have cost production time/money (which Crosley was famous for conserving). Was the original  appearance so objectionable (to somebody) that it needed to be covered by the panel which would have cost more time and money?

The radio cabinet without the enhancements appears to be produced later than the more common version. Did they finally run out of cabinets with the panel and just decide to skip the whole thing? Or was the change made simply to save production costs?

What do you think?

​Russ

Tired of being locked-up. Me too.

Just as we were seeing signs that the SARS-CoV-2 thing might be coming to an end, it appears that our county is going to move back into the "extreme" category.

Since we are not a business, anymore, we are only constrained by good sense, but, we have been adhering to the OR Governor's "gathering" guidelines. We don't want to have anything to do with making one of our radio friends sick.

Still, we remain optimistic. We hope that, by June,  we will be able to reopen the Radio Shop/Museum to visitors. If we start with small groups, maybe by the middle of summer we can accommodate larger groups and clubs.

At first we will require masks. We will also require a completed Covid vaccination card ( you show me yours and I'll show you mine). Politics are not part of this and we don't care to discuss that aspect anymore - or ever.

We still have a lot of restored radios sitting around looking for a display spot - or a new home.  By mid summer we hope to have a "Radio Shop" sale, possibly attended by other local radio collectors who also have accumulated WAY TOO MUCH STUFF over the last year (or years). Dates will depend on so much - If we have another fire season like last year - you might want to bring a fire-hose.

So - - if you would like to set up a visit, send us a message using the contact form. Or if you already have our email address, use that. Tours are still free. If you have an old radio that needs help, bring it along. Any advise (good or bad) or restoration assistance, is also free of charge.

Looking forward to "normal",

​Russ & Sue

Like most radio collectors, there is a point that a person becomes more choosy about which radios to add to the pile - I mean - collection.

For most, this limitation is applied to radios without a high number of tubes or radios that are not rare or valuable (rare does not always = value). Or radios from a certain period. Almost everyone stops buying consoles at some point.

Some collect brand-name radios. Zenith is always popular as are the high-end manufactures like Scott. Crosley is not usually considered a high end manufacture (WLW excluded). This thinking is what led to my comments about passing on Crosley "Fivers". (See posts below)

Well, the WLW is not the only high-end Crosley. In the collection of radios that was donated last year was a 9-tube Clipper which is a 915-EK. This chassis employs a shadow meter rather than an eye-tube so it would be the equivalent of a 10-tuber w/eyetube. Actually, a shadow meter is superior in that this one has lasted 85 years which is very unlikely for an eye-tube. It is a table model. It is rare. Check, check, check! Maybe I should keep this one.

It is difficult to find another picture of the Clipper though the cabinet may have been used on other models like the 1055 EK Constitution from the same year.

There was very little corrosion on the chassis and what existed was easily treated.

This is another radio that had many original components removed and replaced with modem ones. I was able to locate original parts (mostly capacitors) by original part numbers and they were rebuilt and reinstalled in the chassis. Above is an after picture.

Finding original parts to rebuild is becoming more difficult. I have used most of my Crosley-branded caps in recent projects. If anyone has a stash of old parts that were removed from any early radio, I could use them for rebuilding and that would be superior to using them to line a garbage can (clink). (You can always ID a bad paper cap because it goes "clink" when it hits the can)

It is tough to compare this radio with other manufactures products such as the Philco 116B since the small speaker that Crosley used is clearly inferior to the 10" used in the Philco (which also uses a shadow-meter)

​https://www.russoldradios.com/blog/big-philco-tombstone-116b

The cabinet was in good shape but had been refinished - so I refinished it again.

Colored dots on the band selector match band colors on the dial.

Pictures copyright Russ' Old Radios

Most mornings I spend about an hour answering radio-related emails. Many fall into the categories of :

How do I get my radio fixed?/ help with repair.
What is my radio worth?/Will you buy it?
What kind of radio do I have?

This Email falls into the last category. I found it particularly interesting, so, with permission, I am posting it here.


Thomas from Stockholm said:

Dear Russ !
 
 Our family owns this very old big radio that used to belong to king Gustav the 5th of Sweden in the 1930 ´s . Would you with your expertise now what model it is and when it was built ?! 
 
We would truly appreciate your knowledge!
​

It is a very large radio/phono combination.

I suspect that the switch, center/rightt is a radio/phono switch as you would find in a Panatrope of this vintage. (Panatrope was the name used by Brunswick a company that used RCA radios up until the time that RCA acquired Victor)

Looks like a Radiola escutcheon without the RCA/Radiola text.

It has an Electrola decal.

This was my reply:

Thomas,
 
The radio section its self appears to be a RCA Radiola 28, but that is not the model number of the whole assembly. 
 
In 1927 and 1928 RCA was in the process of acquiring the Victor Talking Machine Co. That is where the RCA Victor name came from. This is an Electrola, a name denoting the electric phonograph as opposed to a wind-up model. It is likely to say Victor talking Machine Co somewhere on it. The gold escutcheon near the roller knobs would have said “Radiola 28 Super-Heterodyne Radio Corporation of America had it not been made to be put into the Electrola (Victor) cabinet.
 
I do not know the model of the whole RCA Victor cabinet/assembly Which may have been a very limited production or even a custom assembly.
 
If you were to send larger pictures I might be able to tell more.
 
If you like I could post your pictures and story on my blog. Other people might know more about it and reply.
 
Russ

Radiolas are not my specialty. I can tell you about the many versions that I have worked on - This is not one of them. The radio is in storage so no additional pictures are available at this time.

Thomas is going to monitor this blog for comments, which are invited.


Steve, on ARF Said:

​That looks like a Victor Hyperion. That is quite a radio/phonograph!

https://www.radiomuseum.org/r/rca_hyperion.html

-Steve


Fran, on the Philco Phorum said:

​Greetings,
What the king had there was a Victor Hyperion (Victor model Fifteen-One).  !926 to 1928 which listed for $900.)) US.  The radio was an RCA Radiola 28.  This was Victor's first all electric Orthophonic Radio - Record player combination.  It is described on page 222 of Robert Baumbach's book - Look for the Dog (first edition).
There should be a plate within the record compartment (to the rear of the compartment on  or adjacent to the motor board) with the Victor model name and number.
It was impressive at 57.25" High, 47" Wide and 19.5" deep.
The cabinet styling was Italian in nature, using walnut and maple.


Michael, posted this on ARF:

Here's some info on the Hyperion: http://www.victor-victrola.com/Hyperion.ht
​

https://books.google.com/books?id=Ck9IG ... or&f=false

Vintage Hyperion Upgrade: hhttps://forum.talkingmachine.info/view ... 9&start=10

You Tube: https://www.youtube.com/watch?v=v1LdVTMcBTE

​Buster Keaton

Thomas has provided a history of the radio:


 Briefly ….   :  my granddad ( founder of Centrum radio )  Bertil Gylling senior delivered his famous ” Centrum royal map radio" 1933 to King Gustav the fifth, 
in return from the royal castle he got the Victor Hyperion to store or just take care of . The Hyperion has been kept in its ”BOX”  since then. 
The "Centrum royal map radio" came about from a joint venture between the King and my Grandfather.  A map over Europe was displayed on the ” lock ” over  the radio & gramophone ”   and  when one  of  33 european stations
was reached a light showed where on the map the station was situated   ,  for example  Wienna or Copenhagen    .    ( se pic  )    ….  high tech in those days. There are  only 3 left in the world of this radiorarity . 
My father Bertil Gylling ( 92 ) is still around to tell the story .
 
If you want to se what the factory of Centrum looked like in the 30 / 40 ´s     check this  film  (  in Swedish  ……  ;)  )   the part about Centrum start after ca 3 min after an episode about Violins .  very old school cinema reportage style …
 
https://www.filmarkivet.se/movies/den-underbara-tonen/
​

at the royal castle in the 30 ´s   more or less every day  a  sort of  ”   Lord Chamberlain ”   played records  mostly classical music to the King &   entourage,   you see the  Centrum royal map radio and how its placed +    stacks  of 78 records  in special  shelfs  :
​

We all appreciate Thomas and his family for sharing this history with us.

Don't miss the radio assembly video (link) that Thomas provided. It is one of the best that I have seen. Makes me feel old when I see that young woman throw the big table-top into its box - I have a hard time lifting those onto the bench.
​https://www.filmarkivet.se/movies/den-underbara-tonen/

​Russ

Meissner was mostly a radio parts supplier who also produced "kit" radios to be assembled by the user. They were part of Maguire Industries Inc.

I believe that, like many manufacturers in the radio business, they wanted to show what they could do and the result was the 2961. 

Produced around 1947, the radio is AM-FM-SW with a Webster phonograph and 29 tubes.

As rare as the radio is, there are even fewer with cabinets. While I have not weighed this monster, it has to check in at around 100 lbs. The cabinet is well built, but the weight probably added to the demise of many cabinets through rough handling.

​I generally don't care for late 1940's cabinets but the wood work on this one makes it stand apart even before you open the doors.

The radio incorporates a separate amp/power supply. The amp uses 4 6L6GA tubes in PPP (parallel push pull ) configuration wired for triode operation. This yields about 20 watts output which is a considerable reduction in output from what a 6L6 amp with a pentode configuration could produce. The sacrifice was made in an attempt to produce better audio quality than a pentode could (in theory).

Above:  I know this resembles the scene from Star Trek  The City on the Edge of Forever  just before the radio blows up, but let me assure you that there were no flames here.

https://lancemannion.typepad.com/.a/6a00d83451be5969e2019b00e60fea970c-pi

As fun as that would be (flames) it would also be a tragedy since the picture above is not likely to be repeated any time soon. Just  one of these amplifiers is so rare that having a pair for stereo is likely unheard of.

​It is as unlikely as having two Zenith Stratospheres on the same bench - -

 - - Well I'll be darned, two Zenith Stratospheres.

​Anyway, I did add a preamp and had a listen using the speakers in my office.

TWO Meissner 2961 amps wired for stereo.

How did they sound? OK. Like many high-powered amps, they seemed to lack a little on the top end (treble response - NOT tribble response - she can't take much more of this)

In a way I was glad that they did not sound great since they take up a lot of shelf space and I might have never put the radio back together again.

Interesting that the FM dial is "channelized" rather than reading in frequency as most modern radios do. This format was adapted from the previous FCC channel allocation (around 42 mhz.) but it was generally dropped following the war in favor of the 88 - 108mhz display format. This leads me to believe that the design was from 1946 or earlier. It probably took some time to put such a radio into production especially in such limited numbers.

​The channel numbers on this FM dial are 200 to 300.

The control area is leather and is normally protected from wear with a clear plastic sheet, removed here to reduce glare.

The upper row of push-buttons are for bass and treble control and work considerably better than the more common "tone" control. The lower row are for AM (only) station presets. The station presets are controlled by the row of knobs at the bottom. This arrangement makes setting preset stations easy. The radio drifts very little so there is no need to fiddle with the controls after selecting a station.

While the outside of the cabinet had been refinished, and, I refinished it again, the interior, including the speaker baffle, was in good shape, so it remains original - and yellowed by age. One day the new lacquer will yellow as well, but for the moment it is kind 'a two-tone. I believe in preserving as much as possible while making the project function and presentable and, hopefully, future owners will see enough value to prevent the destruction of American Technological Artifacts like the Meissner 2961.

Russ

The phonograph is a single speed, 78RPM record changer with a ceramic cartridge. Watch the demo above.

At one time there was an outfit that would paint your car for $29.95. When I was working at a Motorola S.S. in Portland we would install two-way radios into cars that became taxis. They often got painted at this place. To save time the painter would roll the windows down rather than masking them, too bad about the yellow paint on the seats. These paint-jobs did not look too bad from a distance, up close was a different story indeed.

We have always thought that an old radio would make a great bird house. We even have a radio that Sue named the "Bird House".

Airline "Bird House"

Of course, no birds are living in that one, though, at one time some other small critters might have lived in there.

Of the large group of Crosleys that were donated (see posts below) there were a few that looked real good  - from across the room. On closer inspection, the cabinets were shot. The buccaneer (on the tree) became parts for another unit that had been in the "wood shed" for several years.

Having a donor chassis was a big bonus for this restoration.

I even restuffed the candohm that had an open section. Would I do this again - well - I did on the Crosley Clipper ( 9 -tubes, rare, more later). This is kind of a pain and I would not do it for a common radio.

I am pretty sure that there is an eagle living in this one - though it might have just been a sparrow. Why don't you stick your hand in there - - - 

As mentioned previously, Bill Reid has donated  the remainder of his collection to the museum. I did not count, but it was several hundred radios in total. Bill's main interests were boat-anchors/amateur gear and radios produced by the Crosley  company, mostly from the 1930's and 1940's. (more on the big receivers later).

So when I was not playing fireman (see post below), after the soot cleared from the air, I was able to work on a few of the cabinets. I had started with the big 8, 9, and 10 tube radios first. When I came to the 5-tube radios that Crosley called Fivers  I would normally have set them aside, possibly offering them for sale as projects, but here was an almost complete collection. I saw it as a case of the total being greater than the sum of the parts, not to mention one of the fivers being a 25 Hz mains unit.

These radios were all restored as a group. The cabinets were finished with nitrocellulose lacquer that had been slightly modified for less gloss -  between gloss and semi-gloss. All of the cabinet had been refinished previously and several were missing parts, mainly base molding, which I reproduced with my table router.

The chassis had also been worked-on. Some of them did function and a few, particularly the 25 Hz mains unit (center) did not. Check out the size of that 25 Hz transformer! This thing is heavy and the chassis weight might have tested the rather simple cabinets.

The later chassis (typically 517 model) is on the left and a 515 is on the far right. The 25 Hz unit is marked 555-5. YES(!) Crosly model designation can be confusing. On the web you can find examples of the model 555 and a console model 5555 but don't confuse either with this one (555-5).

The chassis had many parts missing/replaced. So I had only a few of the correct by part #, original capacitors to rebuild. My stock ran out after the first couple of restorations so I had to improvise. I did use the correct brands - Crosley was not picky, Solar, Sprague, CD and Aerovox are a few of the original paper caps that can be found with the Crosley W-XXXXX part numbers printed on the caps. The other issue is that Crosley was fond of multi-section paper caps. These are seldom seen in other manufacture's units. Basically, you have a paper tube with 2 caps in it. This assembly has a lead exiting the center of the tube which often is soldered to a mounting clamp. This center lead is often connected to ground.

By now you are probably wondering what this has to do with Greek Muses.

Thalia is the Muse of comedy and Melpomene is the Muse of tragedy. They are often seen pictured together in the theater - one smiling face and one with a frown.

Still unclear? Well, remember when I brought you this? https://www.russoldradios.com/blog/heres-looking-at-you-hes-looking-at-you
Too many lacquer fumes, some say.

​Had I not restored these as a group I probably would not have noticed - 

I probably would have never noticed that the later 517 looks less-happy than the early model.

Note the differences in that one uses a bezel and one doesn't. More to the point, the two router cuts on the right and left of the grill are different. The shorter ones seem to replicate a sad face while the longer ones make the cabinet look happy.

In trying to find original examples of these cabinets I noted that some seemed to have gold paint in the groves rather than black. So I did one each way.

​Too many fumes? Maybe.

The scene from our back-40 yesterday as the Worthington Fire grew quickly to over 500 acres. It is not yet fully contained today. Temps over 100 deg. F.,  humidity  in the single digits, wind gusts ~15 mph.

This post is a continuation of the "Farm Radio" post below.

When I purchased this radio off of P-Bay things were Covid-slow. So I decided to do a more in depth restoration of the chassis. Little did I know that Bill Reid was going to donate the rest of his collection - about 3 truck loads, but, more on that later.

You usually see this cabinet with chassis #5516 which would make it a model 5-S-127, one of my favorite radios. Those are not uncommon. I think that the radio was as popular at the time of manufacture as it is now. There seem to be quite a few around, but popularity has driven up the prices above comparable radios by other large manufactures. 

Above are a pair of 5-tube AC powered chassis. There was a lot of variation in this chassis construction. Even for the 60hz models, there were at least 2 transformers, at least 2 different speakers with different field coils which also created some circuit differences. So if you work on one of these be sure that you have the appropriate schematic.

Other than the components, there was also a painted and a plated chassis that often has green, rusty patches like the one above.

The battery powered chassis has a different layout than the AC versions. Somehow I failed to take a proper "before" picture prior to the removal of all of the rusty/corroded components. With everything removed it is easier to see the extent of the rust above. Note that there is no cutout for a power transformer.

I don't like to paint chassis that were originally plated. Besides the issues with ground points being corroded and subsequently , painted, I  just  don't want a radio that has been altered in that way. SO it was time for MORE FUN WITH CHEMICALS AND ELECTRICITY!

 I had a disk brake hub that was keeping a tarp from blowing away. If you are going to de-rust steel a steel anode is necessary.  NEVER use stainless steel. 

​The white powder is washing soda, easily found at WM.

Just add water, hook your chassis to the NEGATIVE lead and suspend it in the solution, not allowing contact with the  steel plate.

I am avoiding using the term "Anode" here since it can be confusing, ESPECIALLY for a person that is accustomed to working with vacuum tubes. If you want to get it straight in your head, you will have to do some reading and I did not want to bore you here.

The result will be a stream of bubbles coming off of the rusty chassis and a nasty looking film of orange gunk will float to the surface eventually sinking to the bottom.
THE GASSES EMITTED IN THIS PROCESS ARE COMBUSTIBLE  and that is why THIS SHOULD ALWAYS BE DONE OUTSIDE. And, if you are not absolutely sure about the technique DON'T DO IT AT ALL.

Remember when Circuit City  went out of business? I went to the liquidation sale, late in the day. There I found the power supply that had been used for the car radio display and managed to acquire it for $25. I was not sure what I would use it for at the time - but now I do. You need a LARGE DC supply for rust removal. It does not need to be well regulated - or regulated at all, but you will need a few amps and 12V is a good voltage. You can use a car battery if you missed the Circuit City sale.

Then all you have to do is replate the chassis - NO, not with copper, with nickel, then with copper. Acid copper (bright copper) plating solution is too acidic to plate steel. Instead it will just turn black/nasty and corrode some more.

You might want to fill some of the pitted places with solder - easier said than done. Solder works best on the nickel plate rather than the bare steel. Use an iron - NOT a torch.

I really don't do this all that much (and for that reason, take my advice with a grain of salt - like you usually do). I was happy with the results. Kinda' PINK, but it will be the color of an old penny after a while.

Did I mention having to remove EVERYTHING from the chassis including all of the riveted components? Well, now you have to put it all back!

Some people use bolts or screws. I use rivets like the originals, besides, isn't hitting a chassis with a hammer something you have often wanted to do?

​BUT WAIT - THERE'S MORE!

Almost every metal component on these chassis are plated with something. The tuning cap is plated with nickel (not the aluminum plates) and the IF transformer cans are plated with zinc. Talk about dissimilar metals! I think that the cans needed to be plated to avoid corrosion of the base metal which seems to be aluminum. 

After dealing with the nickel plated components I moved on to a new challenge - zinc plating - which is supposed to be easy(er).

Above: IF and RF coil covers.

As found
Sanded/cleaned up
Replated

​Keep in mind that I am showing you what I did, not telling you to do it.

​Below is the configuration I used for plating zinc. The zinc foil, which is very soft/bendable, was purchased for very few $ off of Amazon. The plastic bowl I borrowed from Sue. I don't think that she will miss it - - or want it back. You must use a variable voltage power supply. So the big sucker pictured above will not do.

I easily formed the foil to the shape of the bowl insuring electrical contact for my + connection. The part was hung off of 14 ga. copper wires and the little pieces of paper insulated against shorts and subsequent explosions. (see gasses are explosive above)

At this point I should mention that I performed this process on the 5516 (AC) chassis, pictured at the top of the post, as well as well as the battery powered chassis that was going back into the cabinet. I have found that once a process is started it is easier to continue rather than restarting (and relearning) it later. So the pictures of re-plated items are a composite of both chassis.

The IF/RF transformer cans came out a dull grey, just like I expected them to be. During the plating I noticed that the zinc could appear more like a galvanized finish if I deposited less zinc on the base metal. This included the wavy lines and markings typical of a galvanized surface. So if you like that, stop sooner.

Some more notes:

I needed a dielectric to transport zinc ions and water alone will not do - maybe salty water, but I did not try that.

I saw somewhere on the internet (source of all wisdom) that a person could use the washing soda used in stripping the steel to make a solution. I tried this. One way to see if your setup is working is to monitor the amperage on your power supply and watch for the small bubbles. There were bubbles - and bubbles - and nothing else.

So I decided to ditch the washing soda water for clean in which I deposited about 2 tablespoons (use plastic spoon) of battery acid (sulfuric acid) - - do I really need to tell you not to do this?   Anyway,  now there was some action. At first I needed to set my supply at about 15 volts . BUT, by the time I finished 4 of the cans I had dropped the plating voltage to about 1.5V.  (that is one and a half volts)

​I suspect that the process formed zinc sulfate in the dielectric which encouraged the transfer of zinc to the plated surface. Had I maintained the 15 volt initial setting, I would have destroyed the can and the foils and - you know - sparks, fire, explosion. So if a person was to try this - and I know that you won't - careful monitoring is absolutely necessary.

​Zinc sulfate is a component of fertilizer, but I would not pour this stuff on the flowers. I dispose of chemicals responsibly.

Both chassis above. I could have plated the tube shields s well but they were not in bad shape. This is a good comparison of the DC and AC powered chassis.

Above and below are the before and after pics for the AC chassis

It should be noted that it is difficult to "throw" the plating into the corners of the chassis. And that I stock the original Zenith caps for those chassis that have lost them.

Thanks to Harry L. for a lot of those old caps.

Above and below are the before and after pictures of the DC powered chassis

Now, back to specific differences between the AC and DC powered radios.

The cabinet used for the 5-F-134 is different than the one used with the AC chassis. Note the 2 wooden brackets near the top of the cabinet. These are used to slide in a vibrator power supply which would have used a 6V battery as a power source. The brackets, along with some other modifications, make the battery radio cabinet heavier than the AC chassis cabinet. 

I had always thought that a radio with the brackets and without the vibrator supply was simply missing that supply. But, no, there is another configuration for storage batteries, a setup that would be familiar to users of mid 1920s battery radios.

On this DC powered chassis there are 2 plugs on the top surface. One is to plug in the vibrator supply (right) and one is for the dry-cell batteries (left). On a radio optioned for dry-cells there are 2 heavy jumpers installed in the vibrator supply plug - see above. In this configuration a cable was provided to plug into a dry-cell assembly, A, B and C cells.  So, on this chassis, the A supply was 2 volts and 2 volt tubes are used. The radio works well with about 140V on the B supply. A C- supply could limit current consumption of the final audio output tube.

​So it is perfectly normal to have a radio that does not use the top mounted vibrator supply.

Of course, while I was having all this fun the lacquer was drying.

It looks even better in person.

I have already started on some of the radios donated by Bill and some of those will be up next. Along with the old radios is some tube-type audio equipment, which I find interesting and useful. Though I have restored a lot of tube-audio gear, I have not posted much about them. Maybe we'll get into that next time.

Russ

 - -and thanks Bill for filling up my shop ;-)

Bill Hennessey  has compiled a spreadsheet on the differences between the early model AC chassis and the later one:

In the interest of working out the differences between Chassis 5516 Var. A and Var. B (the original subject of this post) I have created a Google spreadsheet with the stated values for the two known Schematics involved. I've also put in place the values as recorded by bastardbus for the Chassis 5516 Var. B.

There are three tabs in the spreadsheet. One tab for the 5-S-127 Chassis 5516 Var. A (Rider 7-7 Schematic), the second tab for 5-S-127 Chassis 5516 Var. B (no known schematic, values from bastardbus), and the third tab for the 5-A-127 Chassis 5517A (Rider 10-15 Schematic).

Those values listed in Chassis 5516 Var. B and 5517A that substantially differ from Chassis 5516 Var. A are in Red.

https://docs.google.com/spreadsheets/d/1U_oBMYzxQR48MkZR6t7u7yo2bScMciomPMwI2XKKk8E/edit?usp=sharing

I offer this in the hope it may help us to more easily track these capacitor and resistor values and provide some additional guidance to those hoping to restore their Chassis 5517 Var. B sets.

Let me know if there are any additional values or data that should be considered for inclusion here. Right now, I've set this Google spreadsheet to allow comments, feel free to add comments on values that you have found in your own sets.

Thanks!
_________________
Michael Hennessey
mbhdesign