Above are a pair of Crosley Bandboxes. Along with many of the metal-box radios that Crosley built they suffer from almost universal pot-metal component failures. There are about a dozen cast parts that are critical to the radio's  operation, so much so that a single failure will stop most restoration efforts.

I have salvaged a few of these unfortunate specimens, but realized that the spare parts were only good for other unrepairable models. So why bother keeping the parts?

The metal-box radio pile also had 4 AK 40s and a pair of AK 37s, also among the restoration challenged. These will be discussed at greater length below.

Above, the stator found in the Bandbox. This one has had it. The cracking/swelling pot-metal has caused the stator plates to contact the rotor plates. People have tried bending the plates so they don't touch but the linearity is  lost in doing so especially since this is true for all 3 of the variable caps. The best that can be expected form such an effort is the ability to tune one or two stations with the rest of the tuning range, useless. Even if such a repair is quasi-successful, time will eventually lead to further expansion of the metal and failure.

Below, the pot metal bracket, through which the rotor control shaft must pass, is also deformed and binding. Most of these look much worse than this one.

Below is a collection of these pot metal parts as well as the proposed solution. Note that the pot metal on this stator is in much better shape. Chances are good that one day this too shall degrade but I am going to use this one as is. The bracket(s) were not so fortunate.

At the bottom of the picture are 2 plastic replacement brackets and one has been installed in the assembly (center).

While I was already on the path to design replacement parts, I had not settled on a method.  I was moving towards recasting the components in resin when I found an old article showing the parts being made from old plastic decking. This article seems to be missing now, or I would post a link.

Since I had a pile of old deck material out on the "back 40" it seemed like a reasonable  idea to give it a try. The old material that I had was an inch thick (newer material is only 3/4" thick and has a laminated wood-grain, not recommended). It is easy to shape on a table saw. It is easily strong enough and accepts wood screws, so the original machine screws/nuts will not be reused.

Now, from memory, the article mentioned above said that he had trouble with tracking/linearity and that is easily possible. Here are some notes to avoid that.

1. When cutting the brackets, shape the material in long strips. In other words shape the material by width and thickness, making all cuts possible prior to cutting it into equal length chunks. This will improve consistency.

2. The hole required for the rotor shaft must be drilled on a drill-press. It must be accurate and STRAIT! Do not make it over-sized, just adequate for the shaft to be pressed through the hole. Note that the hole is off-center.

3. A ground must be soldered to each of the copper retaining clips shown above.

4  Make sure that each of the mounting screw locations is identical.

Above: This is the assembly that reused the original stators. Both of the pictures below show the unit in which I had to rebuild the stators using 3" #6 bolts and stainless washers. If you use larger hardware the rotor will impact the stator at the full closed position (or earlier).

The original tuning drive gear bracket is also pot metal. I thought that this was going to be a challenge. Thanks to the ease of working with the plastic material, it was not. The shaft is pressed into the gear and will require a few gentle taps to remove and reinstall. I shaped the rounded nose (passes through the escutcheon) with my Dremmel tool.

There are 3 more parts that must be addressed. And here is where the AK-40s come into the picture. The pulleys used on the Crosley were also made of pot metal as well as those used on the early AKs. Fortunately AK began to make them from brass at some point. So, below, you see that the outer 2 pullies have been replaced with brass AK parts. Note that the center pulley is the original with 3 screw hole used to mount the dial/gear. Great, right? No. Again tracking will be affected by this lash-up since that original part is slightly larger in circumference than the brass units.

The solution to the tracking issue is to drill mounting holes into the center brass AK pulley and use it as well. The holes will have to be tapped to use the original hardware. Luckily the original Crosley bands are adjustable enough to accommodate the slightly smaller pulleys.

At this point I should note that the Crosley is a good candidate for this "mod" since it's original "one dial" construction incorporated 2 additional trimmers used to compensate for tracking errors in the original 3 tuning cap assembly. These trimmers/padders are the 2 levers located on the far lower right and left.

For some reason I found it easier to use these trimmers in association with the far right and left caps rather than the left and center as originally built. This only required moving one wire.

A couple of more notes on this radio.

Shields must be in place for alignment. There is a lot of gain in this radio. Stage coupling is an issue. Mine work best with low value grid leaks ~ 1m or even less. The first tube is mostly used to decouple the antenna/ broadband RF amp. You might find that the radio works just as well with this tube removed. Not suggesting that you do that, just an operational note. I found that on strong stations I was running the filaments well below 5V. It also works well with B+ at about 65V and audio final  B+ at about 90V so you can lower your C voltages as well.

Now, About those AKs. You might ask why I borrowed parts from one to rebuild the Bandbox. After all the AK was probably a better radio. I think it also looks better. It is AC powered rather than running on batteries like the Bandbox. The early AK metal box radios also had pot metal pulleys, but that was not an issue here.

It seems that there is a radio-myth regarding the potted power supply that says that for some reason the filter caps are often good. This is just a fantasy. The effort needed to resolve this issue is beyond what most people want to invest in these rather common radios so it is easy to adopt this mistaken philosophy. The result is a radio with melted tar in the bottom and a failed power transformer - which leads to the second myth - AK power transformers are weak, which is also wrong. This, however, is a good way to end up with a parts chassis as was the case with several of the ones I had.

So, rather than hoping for the best, how can you judge the viability of one of these power supplies? As seen above a simple measurement is the best way to start. There should be more than 200V on the B+ when the radio is in operation. Much less and your radio is headed for the parts-bin. Even if the B+ is only a little less, say 180 - 190V this indicates excessive draw which is likely leakage in one or all of the filter caps.

Below, you can see what is inside of the "can". The best way to service the filters is to gently warm the entire power supply can in an inverted position allowing the tar to run out into a metal container. Other methods usually result in damaged components. Only enough heat is required to melt the tar. This temperature is not high enough to damage the paint on the can.

The added benefit of rebuilding the supply is the ability to replace the original wire which, by now has become brittle and unsafe.

Below you can see the components, rewired and repositioned in the can prior to replacing the tar. The 2 studs in the center are the ground. Sometimes it is best to bend these tabs upward to allow for easier passage of the components. It is always beneficial to remove the 2 nuts/bolts.

Another tip is to cut all of the wires as short as possible prior to melting out the tar. This is especially true of the wires leading to the rectifier socket. Also remove the cork found there.

Below is the underside of the rectifier socket. Cut these wires as short as possible to prevent binding as the tar is removed.

Don't forget to service the 2 glass-tube resistors on the B+ and detector B+ while you have the supply apart.

It is easy to forget about the bypass cap that goes between contacts 3 and 9 since it is the only one that does not have a leg going to ground (and is not one of the filters).

Above: repotted prior to reestablishing the connections on the power supply board.

Now, you will have to find parts for your Crosley elsewhere - - -

Four or five years ago the hard drive on my HP Media Center desk-top was dying along with Win XP support. It seemed wasteful to throw it out after all it was only 10 years old (ancient). So it sat in the garage until it got in the way.

Surely there must be something useful in all of those drives, memory and processors. Na, not really, except maybe the 300W power supply.  These supplies provide 3.3, 5, 12 and -12 volts, well filtered with lots of current available. Do any of these voltages seem familiar? Well for me I quickly realized that this would make a great supply for those old 1920's tube radio filaments. Fifteen amps at 5V. You can run a lot of 01As off of that and a few (dozen) more 199s from the 3.3V. Too bad that the supply is not isolated and has no HV output.

Still it looked like an interesting project so I removed the supply and scrapped the rest. It took about an hour to replace the electrolytic caps which are usually the cause for failure in these devices.

If you traveled to Europe in the 1960's, you might have carried one of these adaptors with you - just to run your US electric shaver. Not so necessary now and likely to put a dent in your airline weight allowance - or anything it crushes in your suitcase - but great to convert to an isolation transformer (left of the PS).

So now I had isolation.

I should mention that both of these parts/assemblies could add a significant cost to this project IF you have to buy them, but, they should be relatively easy to scrounge.

NOT! Now I needed to hit the internet, since, I could have built the HV supplies and the metering, but why spend a week on a $3 part?

Most of what I needed was available on E-Pay or Mouser and when all was done it is interesting to note that the meters and inverter supplies cost about the same as the connectors. The banana plugs and alligator clips all came from Mouser, quick and easy. Trying to figure out what to buy on E-P was a bit more challenging.

I needed A, B and C voltages. The A and C were already available from my old computer supply but B+ would need inverters. I had plenty of 12V, so an inverter that would give me up to 200V running off of a 12V source was needed. There are plenty of cheap, mostly Chinese, supplies on E-Pay. None of them have schematics or specs beyond absolute ratings. The same can be said for metering.

I needed meters suitable to monitor the B+ (200V). It would be nice if they could be used for the A and C voltages as well. For about $3, inc. shipping, I found these. They also incorporated an amp meter good to 10A.

The 3 inverter supplies I chose could produce about 5W output. So as voltage-out increases current must decrease. At 180V that is about 27ma. Good enough for several 171As and 110ma at 45V, good for a lot of 01As or 199s. Fortunately they can protect themselves from over-current. UNFORTUNATLY both the meters and the inverters are common ground.

I was also going to need a cabinet. Something resembling a 20's radio would be great. Something with a small footprint would be better. The top is screwed on so it can be removed for service and the front panel is only held by friction/fit so it too can be popped out for service.

I bought a rough, 1' thick mahogany plank. I needed about 2 board feet for this project at a cost of about $6 per BF. I saved the rest. I thought that the slanted panel look would be accommodating on the bench and used a piece of 1/4 inch plastic for the panel with the back side painted black.

Cutting all of the holes in the plastic panel was a pain - probably the hardest part of this project. But, I managed to get it close enough on the first try.

As mentioned, the PS was going to be common ground whether I liked it or not. Really not to big a deal but issues include:

Current metering - since the meters measure amps through a shunt to ground (return), the current must be added if more than one ground is used UNLESS the device has separate isolated return(s). If each A, B or C voltage is being supplied to a separate, isolated, device no problem using each meter to monitor current consumption. SEE the video in which I use the A supply to monitor all current consumption. A meter with the shunt on the + side would have been much better allowing metering on each source. Also, the meters require 4V - 28V for their own supply, which is also common ground.

No output can be arranged in series. For example 100V + 100V = a short since the + can't be wired in series to the next source ground.

Issues for isolation to earth ground. Note that I added a green ground connection, which works for me since the shop is the only building on the ground and electric co's transformer. Performance elsewhere might be noisy - at best. Isolation transformer required.

C voltage is available from the computer supply but care must be observed in wiring. From my supply I can generate up to -12V but the meters will not measure - voltage. This means that the + side of the meter must be to common ground and   4V to 28V must be provided to run the meter without causing a short. An additional C voltage could be added using another variable. No current will be indicated by the meter since the C connection on your old radio draws almost no current. The C source needs a load resistor - about 100K, just to keep the associated rheostat within a reasonable range. My control is 5K to 25K. If your control is 0 - 25K, add a series 5k resistor.

Schematic for the Freed Eisemann test subject showing the power connection color code used on the PS.

The Freed Eisemann 50 is a 6 tube TRF with 01As in all positions except the AF output being a 171A.
All of the metering really help in trouble-shooting 20's radios.

There is a small amount of hum but it is coming from my part 95 transmitter rather than this supply.

Note that the B+ current indicated on the 5V supply meter is about 15ma (1,242 B+ off to 1.257 B+ on).

ONE MORE NOTE on these meters - One reason that they may be so cheap is that the 3rd decimal point never lights - 99V reads 99.00 but 100V reads 1000.

Also, cool in the dark - see video.

Russ

UPDATE: In a related discussion on ARF there was some desire to raise the voltage on the 5V supply to  near 6V.  A simple modification to the 5V metering will raise the 5V supply to 5.6V and the 12V supply to 12.8V. This is accomplished by dropping the voltage on the pink wire by connecting a 2K resistor from that conductor to ground (any of the black wires). It is likely that 6V or higher can be achieved through other modifications, but, using a resistor smaller than 1.5K will cause the supply to shut-down.

5.6V is more than enough to power 01As and the like, allowing for some attenuation through the radio's filament control.

 - - "Just throw away the turkey." YUM!!

Speaking of turkey, take a look at this one.

This is a 1946 Zenith "Universal" or "Wavemagnet" set that is a close relative to the TOs discussed below. It is the YX version (6G001YX) which is black vinyl covering an aluminum cabinet. The majority of these came with a wooden cabinet which I prefer, but, none the less, this is an unusual model deserving restoration.

Above: As Found
This chassis worked but the audio was low, there was an intermittent crackling in the audio and the antenna seemed to be ineffective at best (loss of gain in RF stage). It had been about 1/2 recapped.

The repair incorporated a lot of these twisty-splices. They are similar to some splice/repair aids sold around the same time as the radio's manufacture, though these are home-spun. The idea was OK if "getting it working" is the primary concern, but, the one above, and many of the others could have used some more solder. Mostly, they just add to the unoriginality advertised by the "yellow caps".

Note the Zenith cap barrels on the bench to the right. They were pulled from my replacement stock and will be used to replace the yellow caps.

The filter(s) can had been restuffed, but incorporated more twisties and rather than making a direct connection to the posts, the electrolytic caps had been spliced to an insulated wire and protruded through a hole in the center of the base. This made for an ugly, busy, repair which also included a new ceramic resistor (5W wire wound, original was 2W).

Most Zenith Chassis are full of orange "Zenith" paper dielectric caps. I would suppose that shortages drove the factory to use non-Zenith labeled caps at times. I would say that there is about a 99.9% chance that these are original since lead dress was exactly like the Zenith labeled caps.

I can almost visualize the meeting where engineers at Solar concluded that burying their paper dielectric caps DEEP in a wax body would prevent moisture from intruding into the paper, which caused failures. It didn't help. They still fail at about the same rate as the orange caps though the leakage might be a little less.

What is for sure is that restuffing one of these is a challenge. There is a paper label but it is not strong enough to be used like the cardboard tube of the orange ones. In earlier restorations, like the Westinghouse refrigerator, I carefully cut and extracted the original cap from the wax, but only succeeded about half of the time. There has to be an easier way, and there is - -

Above: the first step - remove the original label. About 3/4 of them will slide off with no trouble.

Below: Use 2-part molding putty to make a mold from the original cap (paper label removed first).

When the putty sets-up, pull out the original cap body. Throw it away. The wax used on the original is hard to melt to a liquid state and cools way too fast. I used some wax from another project. The only complaint is that I would have preferred it to be a bit darker brown.

Unseen is the small hole at the base of the mold from which the wire lead emerged. To fill the mold first place the new cap so that it's lead penetrates this hole, but allows an opening to pour the new wax. (trying to locate the hole with the tube full of hardening wax is a bad idea) Melt the wax - I set a metal pan on the shop wood-stove for a minute.

Don't use bee's wax. It is likely to break apart.

Pour the hot wax into he mold then insert the new cap so that the wax flows aroud it resulting in the new cap being centered in the new wax body. Take care that you do not force a stream of hot wax from the mold. This is likely to happen as the diameter of the new cap approaches the diameter of the tube. SO USE CAUTION.
Needles to say, don't try inserting a new cap that is larger than the tube. 400V caps might be desirable as compared to the larger 630V ones. I have asked a couple of the bulk vendors for availability of the smaller 400V caps. I will update as I get more information. The lower voltage caps are available through some of the large jobbers but have a prohibitively high cost.

Let the wax cool and pull out the new cap. Trim any flashing.

Install the old label.

The restuffed filter can was rebuilt again and all of the twisties were removed along with the unnecessary wiring. Most of the original rubber insulated wiring was in good shape.

Chassis reinstalled, aligned and ATP.

The Zenith TO is a Classic regardless of model. The black vinyl covered box is not particularly attractive. You never hear of them being described in terms used for 1930s wooden cabinet radios. I don't think I have ever heard one described as Art-Deco or any of the other common (if still incorrect) terms used in for-sale ads.

No, the attraction to this radio is much more utilitarian. First it was truly portable containing both batteries and adequate antennas.  It was compact for the time. And, most of all, It worked well, really well considering that later models used only 5 tubes. To me, this attraction is more like that associated with some of the early tube testers and other test equipment. This is not the kind of radio that looks good displayed on the fireplace mantel, yet, no collection is complete without one.

What?! Did I just say that no collection is complete without one? Well , I guess that I am going to have to figure out what to do with these.

Above is a G500, the first model to use 5 miniature tubes

Black-Beauties/Bumblebees, probably one of the worst mass-produced capacitors of all time, are a common issue for post-war radios. It is a generally accepted belief that they can not be re-stuffed (rebuilt) and therefore any restored radio that had been constructed using them will inevitably turn out looking like the "before"  example, two pics below.

After: Restoration including the rebuilding of numerous Black-beauty capacitors.

Before: A previous repair which used twisties to avoid cleaning posts, filters mounted under the chassis, rather than restuffing the electrolytic can(s), flying connections (at least 1 miswired),  several varieties of modern capacitors and resistors, and a lot of singed/burnt plastic insulation on wiring.

Having said all of the above, this is still a pretty standard repair ("restoration").

This is why these radios have been sitting around for so long. Even though this example was working, I had considered giving it away or just throwing it out since it did not meet the standards set for the rest of the collection. Selling it to some unsuspecting CL buyer was out of the question. Note as well, that both locating original parts and correct placement was going to be a real challenge.

What I needed was a way to restuff existing, original caps or create new replacements with that vintage look. Above you will see option 1 - restuff the original Black-Beauty caps.

No special tools are required. All you have to do is line-bore the original cap. You can do this with a drill press or just a hand-held drill. What's important is:

Holding the cap securely without crushing it (it becomes weaker as the material inside is removed).

Drill speed, so it does not bind or get too hot.

Maintaining the Z axis (in a strait line).

Making the hole big enough to accommodate the new cap.

Any failure to maintain the 4 conditions listed above will result in a broken/crushed housing, which, if minor, can be repaired with super glue, but further machining will be difficult if the integrity of the tube is compromised. EASY!

An H500 TO looks very similar to the G500 though one uses a  5-tube chassis and the other uses the 8-tube chassis.

OH NOOO!! There are at least three ways to do this!

Which way is easiest? Using the glass tubes.

Which way is cheapest? Drilling out the original caps.

If the original caps are missing, such as in my G500, you must either find originals (I'll bet you have thrown many away), or make some. If you choose the mold method, which is the most difficult to get started, you will need to build a form. I have built several sizes that can be reused. The one you see above has an adjustable base so that thickness can vary depending on the part being made. You can use silicone from the hobby store but it results in a mold that is flimsy and probably will not stand up to more than a few uses. Build your forms sturdy and accurately so they can be reused and most important, so they will not leak as the compound hardens. Use mold release. You will need an accurate scale to mix the components 100/3 by weight.

Though the red stuff is expensive ($90/gal) the hobby-store stuff probably costs more for the same quantity. I am just guessing, but, the HS stuff is probably close to shore 30A, So thicker walls will be needed on the mold so it will not twist or deform.

Cast replacement above. "Sand" resistor needs new sand.

Well - OK, It is going to cost you about $10 to purchase the materials you need at WM. but you will have enough to fix 10 speakers.

SO, you have an AK Type N that somebody (you) put their finger through or Jr. poked it with a stick or whatever. Now it sounds like a nest of bees trying to put on a concert. You could save money by grabbing a roll of TP and gluing it up in a nice ridged mess that looks like a 2nd grade art project or you could fix it right with about $1 worth of materials available at Walmart.

This project requires no special tools, just a little patience. I've dome this before (a lot) so I can do it in about an hour. I would expect a first-timer would need 2 - 3 hours

If your cone is ripped or even partially missing, this job is much easier than doing the math required to calculate the shape of a flat piece of material which becomes a cone,  SO, take care to preserve as much of the original cone as possible. I will mention here that the diameter of the circular cut-out is about 11" becoming about 8" when the ends are glued forming a cone.

If the spider (metal thing in the center of the cone) or the voice coil (see pic. below) is damage or missing it must be repaired or replaced. This article does not cover VC rewinding or fabricating a new spider. 

Begin by unsoldering the magnet wire leads going to the voice coil. Then remove the screw holding the spider and the screws holding the metal ring (3 pieces) around the outside edge of the suspension (pictured 2 and 3 below).

Use a scraper to separate the suspension from the basket (speaker frame). Don't worry about keeping the old material intact, but do keep a piece for reference later when you cut out the new suspension.

The cone should now be lifted out of the basket with the spider and VC still attached.

Sometimes the VC attachment to the cone is so loose that they fall apart - sometimes not. Again, the object here is to separate the VC and the spider from the old paper cone while keeping the old cone as intact as possible since you are going to use it as a pattern for the new cone.

I have found that brushing on a little lacquer thinner around the edge of the spider can loosen the glue. Basically this is a metal ring pressed into the VC that captures the inner edge of the paper cone between the spider and the VC. Caution: too much solvent (thinner) leaking onto the VC will break down the adhesive holding the coil to the former (round tube). So be careful. In the end you will probably have to scrape some of the old cone material off of the edge of the spider since these areas need to be clean before reattachment.

Next, cut the old cone along the original seam allowing the paper to lay flat. Observe the original overlap and allow for the same overlap on the new cone so that the cone can be formed by gluing the edges together.

Above, left to right: Spider, Voice coil and the new cone assembly

Now - or sometime - run down to WalMart and get a folder of black greeting card material from the craft department (about $6). It will have many 12" X 12" sheets of card material that is nearly perfect for early speaker cones. In the same department find a yard of black canvas material (about $4). Make sure that the canvas is cloth, not plastic that looks like canvas. If you can't find black, you can dye or paint other colors (if paint is used, go lightly with black lacquer NOT enamel, which can become ridged). The material should be about the thickness/flexible as your jeans (real jeans not "stretchy" jeans). You might even be able to make the surround out of old jeans.

Lay the old paper cone on top of the new card-paper and draw around the edge. If pieces are missing from the original cone you are going to have to extrapolate the missing circumference from what you have. This can be done simply by rotating the piece that you have around a FIXED center. For this it may be easier to tape the old cone to the new paper and locate the center of the circle and MARK it. This might take some 8th grade geometry and a compass, but you can do it with out the compass. Hint: use the radius - 1/2 the diameter - and make arcs in the center with one leg of the compass - stick - ruler fixed on the outer edge. Three or more arcs will intersect at the center of the circle..

You can lay the metal spider on the marked center and draw around the circumference. Then make a mark about 3/16" inside of the spider circumference since this material must be captured between the spider and the voice coil. Make another circle and cut it out.

The pie-shaped chunk that must be removed so a cone can be formed should be guesstimated from the original. Keep in mind the edges of the cut need to overlap about 1/4 inch so they can be glued.



Now cut the new suspension from the canvas. You can cut out 3 pieces like the original had or just use one. If you use 3 pieces they must overlap about 1/4 of an inch and be glued together to form a ring. These attachment areas can become stiff especially if too much glue is used, so one piece is a lot easier.

You can use a piece of the old surround or the outer lip of the basket to draw a circle on the canvas. If the basket is used, when you make your cut remember that the material will fit inside of the lip so the cut should be made about  1/8" inside of the mark. You will now have a circle of canvas about 11" in diameter.

Use your compass - ruler - stick - whatever, to mark the inside edge of the material. Finding the center as described above might be useful. Use a piece of the old surround material to check the width of this material. There must be enough to reach the outer lip of the basket and have enough to overlap the new cone about 1/4 of an inch. When you are done you should have a ring. The outer edge will not be visible but attention to the inner edge will pay off since it is visible and uneven cuts will look bad.

Glue the edges of the pie-shaped cut-out together forming a cone with the center missing (cut-out for spider/VC)

Lay your new cone on top of the new surround material. Check that there is about 1/4 inch of material overlapping the paper ALL THE WAY AROUND the outer edge of the cone. Use a small paint-brush to spread yellow wood glue on the outer edge of the paper cone and the inner edge of the cloth surround. You can use a contact cement but I have found cones attached using it will fall apart later. Let the assembly dry for about 1/2 hr. If the overlap of the material is uneven it will be difficult to center the cone assembly, so take care.

Now the cone is set on top of the voice coil former (tube) and the spider is pressed into the former capturing the inner edge of the cone between them. Like with the surround, care must be taken to center the components or the cone will be impossible to align and the VC will rub on the pole piece (center of the magnet structure). Make sure that you are attaching the cone to the proper end of the VC former since the voice coil is closer to one end and an error will move it out of the magnetic gap. This is usually a tight fit - be careful not to damage the cone. A little bit of glue will both lubricate the spider/cone/VC connection for assembly and secure the finished product.

Allow the glue to dry for a few minutes.

Put the cone assembly back inside of the speaker basket sliding the voice coil into the magnetic gap around the pole piece. The 2 wires leading to the voice coil should end up at the correct place in the basket which is CLOSEST to the original atachemet points. Not observing this precaution will make hooking up th VC wires correctly - impossible.

At this point the surround should be sitting near the correct position around the circumference of the basket.

The next step is critical - The object is to align the cone/VC so that it does not rub on the pole piece or magnet structure.

This is sort of a three-handed maneuver so before you start, grow another hand or, possibly, ask for help (only required on the first attempt).

What I do is to put the screw back into the center of the spider, screwing it to the pole BUT leave it loose enough to move the spider around. By this point you will be able to estimate the quality of the rebuild by observing the fit of the VC inside of the magnetic gap. It should be loose and free to move BUT it may still rub.

Now, if everything is symmetrical the surround should be laying evenly inside of the outer lip of the basket. Using your soldering iron, Holes for the screws can be punched/burned through the canvas surround. Or you can use a blade or punch but I have found the hot iron easier. The three metal clamps are lined up over the surround capturing it between them and the basket. With the screw holes burnt/cut attach the 3 pieces but leave the screws loose so that the surround can be adjusted slightly.

Placing slight pressure on the inner cone area/spider will allow you to observe the fit of the VC inside of the gap. IT MUST NOT RUB on the pole or the magnet structure. Assuming that the VC former has not been damaged/bent and that the VC wire is still bound to it, slide the spider around on the center screw until the coil is centered in the gap - no longer rubs. Tighten the screw.

If you are having trouble centering the VC slight adjustment of the surround can be made but not enough adjustment can be made to compensate for a cone that is not symmetrical. Glue can be applied around the edge of the basket to secure the surround but this will make further adjustment impossible. Tightening the screws holding the  3 metal clamps is usually enough to secure the cone.

Reconnect (solder) the VC leads to the attachment points.  Use your ohm meter to check the continuity of the VC.

The speaker is ready to test.

If you have any interest in the battery-powered supers of the 1921 - 1928 era, be sure to check out:
https://www.russoldradios.com/1920s-superheterodyne.html
Caution, the page is large, probably too large for dial-up connections.

The Apex Microdyne Superheterodyne from 1925 is an 8-tube battery powered super that was sold as a kit. It has a stenciled panel. All of the transformers are labeled Apex and are comprised of 2 IFs, 1 IF filter, and 2 audio interstage transformers.

There have been a few of these for sale lately and a few more in collections on the net. After examination of the pictures there is one thing that is notable in that every radio is very similar. This is a departure from the typical kit-build that usually incorporates parts and wiring added by the builder. This leads me to believe that either a complete kit that was mostly pre-assembled was being sold or that the radios were completely assembled prior to delivery to the customer.

The ad above is from Radio Digest of Aug 26, 1925. Note the price of $97.50.

As found above. Or rather, fresh out of the box.

The second audio interstage was open. It had leaked quite a bit of the potting material - bee's wax - all over the place. The other transformers had leaked a bit of wax as well. Since the parts of the transformer housing are held together with 2 pins  the seal is poor enough to allow leakage especially if the radio is stored in a warm environment. Cleaning off all of the hardened, sticky wax was the biggest task in restoring the chassis - well - and fixing the open 2nd audio - below.

The buss wiring on all of these kits is very similar. One reason to believe this was built by a radio shop is the remains of a shop claim tag, torn into chunks and used as an insulator/spacer to prevent shorts - Above.

This really wasn't necessary unless the chassis was going to be handled roughly. Possibly in shipping? Which would also lead one to believe that this was a pre-delivery addition by the builder.

Soldering joints, though corroded, are good and no buss wire broke free in transit.

2nd audio interstage taken apart showing potting material - wax.

With the wax removed the transformer is loose. Since it is so similar and not visible I just inserted a standard (156) replacement and wired it up.

The power is wired through a 7 conductor plug (center rear). The 2 black wires connect to a ~4.5V C battery which was located on the chassis.

Even though the cabinet looked pretty good, it was made of mostly solid walnut and the finish was mostly gone leading to warping (the issue with "solid" wood). Sine the panels were several boards that had been joined the warping had split the joints apart as well as twisting them somewhat.

The only way to make it right was to not only bust the cabinet apart but to also break apart the panels and rejoin the individual pieces after making minor cuts to remove the stress that broke the glue joints. Note the lighter new piece grafted to the rt. side panel. This piece was missing. (center right)

Never enough clamps - or hands.

Ta-Da. Sue holds reassembled cabinet less lid.

The finish is med. walnut DYE (not toner) topped with several coats of clear shellac.

This radio does not have an antenna coil like the Victoreen (previous post) so it needs a loop antenna. My test loop is shown above.

Above is a video with the radio in use.

A couple of notes:
Hand capacitance is an issue in tuning. The tuning caps could use some more shielding. The big, brass dial of the Apex vernier is electrically connected to the rotor so it probably makes this worse than when a plastic dial (knob) is used.
The little switch (knob) on the lower left enables the user to select either one or both stages of audio amplification - using 6 tubes or 7 tubes total.  Using the 2nd audio while tuning has some advantages and tone is better (this may be somewhat related to the new audio trans installed in the interstage), But the audio level is adequate using only the first audio stage.
When the radio is "tuned" for the most conservative use of the batteries = lowest A voltage, the oscillator can stop. Turning up the A voltage will prevent this but run the tube filaments hotter.

THIS is, a Superheterodyne kit from Victory Products/ Victoreen.

As with most of the other 1920's superhet radio in the collection, this was a 'kit". Sold as a kit to try to avoid legal complications with RCA.

I am almost certain that this was constructed by the end user rather than a radio shop or other professional and the proof of that resides in the wiring error resulting in a missing meter. More on that below.

This is a rather typical early 20's 8-tube super which uses UX201As. It does have an antenna coil giving it some flexibility as compared to those designs that require a loop antenna, There is even a switch/jack that allows switching between a loop for improved directionality over a long-wire.

This was a stress-inducing purchase from Pay-Bay. The seller is a nice person. She tried to pack it well and maintain a reasonable shipping cost. But even on this short trip, the nature of these 20's cabinets allows a lot of movement of the chassis. The result was a broken cabinet.

All of the cabinet was constructed from solid walnut, which sounds good, but a veneered plywood cabinet would probably broken at the seams rather than splitting the wood. There were split/broken pieces on both sides. Also, plywood is far less likely to warp.

Well, this did make one decision easier. The cabinet was going to have to be refinished caus' no amount of Go-Joe is going to rub out that split.

The decorative trim on the right was broken long ago. Having the trim intact on the other side made it easy to construct a mold and new trim was made (above)

The rough ride broke loose several pieces of the square buss wire used in the original construction. The second audio interstage transformer had open windings, possibly because someone had tried to take it apart. Otherwise, all of the parts were here, less the already mentioned volt meter.

For the most part, the builder used high quality parts. Some probably came with the kit, others might have been purchased separately.

Above is the failed interstage trans. They were produced by a company I have never seen before and in a fashion that is very unusual for an audio transformer. The core was solid iron rather than the usual laminated stack. This solid core was shaped like a spool on which the primary and secondary were scramble/bulk wound. Then the spool was inserted into a iron pipe, held in place with the machine screw (above). Both windings were open so I just wound on enough #38 to fill the spool with a 3 to 1 ratio.

This transformer design is probably not the best for audio quality since the unlamented core is going to generate a lot of eddy currents. This might be the cause of some of the raspyness when using both audio stages in the video (below).

All of the Victory Products transformers were in good shape. This label would seem to indicate an early production date, possibly late 1924.

The original builder did a good job. The positioning of the transformer is slightly different than the later drawings and he used 5 of the 1A glass regulator/resistors rather than a 3rd and possibly , 4th rheostat for filament control. But in my testing the loss of these controls simply made tuning easier with no apparent downside.

Unfortunately it appears that the builder was following a diagram similar to the one below, which is found on several locations on the net. I have made a mark near the volt meter (in red) to note the connection of B+ to the meter. (Above) is one of the buss wires that fell out when the radio was unpacked. As with the diagram it appears to run from B+ to the meter location resulting in 3 conductors/connections for the meter. Now, most meters only have 2 connections, + and -. And I can not recall a meter of this vintage that needed 100V DC for anything. I suspect that at some point high voltage damaged the original meter which is why it is missing.  I used a meter from a Radiola to fill the holes for pictures but it is wrong.

Cleaned up, rewired, resoldered, polished and repaired (below).

After checking the A circuit, I brought up the B+ and there was a station playing LOUD and clear (Faux Sports). I cant recall this ever happening before, at least SOME tuning had been required.

This radio has such good gain that the 2nd audio really isn't necessary AND it appears that the builder also knew this since he incorporated a slight mod to the last audio jack that turns the filament off when the 2nd audio (201A) is not used, saving some A battery life. To commemorate the builder, I left this mod in place.

Below is a video I shot just after powering the super up for the first time (for me). The meter would be reverse polarized with the original wiring so it is for looks - now. The fateful B+ conductor was omitted in the reconstruction.

The drawings for this radio in Rider's vol. 1 do not show the meter to have a B+ connection and are very useful to a person needing to do some reconstruction on one of these radios.

Duane had said that the meter might have been a switchable unit allowing the user to check/set both A+ and B+ voltages. I knew that such a meter would have to have had an integrated switch since there was no facility for an outboard switch on the front panel.

Harry was digging through a listing for a group of old meters and located the one pictured above. Not only does it work, but, this Jewel meter matches exactly the buss wire connection/position of the original construction. That makes it likely that this was the type of meter original used.

Thanks Harry!

Harry said "Hay, before you put away the plating equipment why don't you try to make a Radiola 18 hood?" Well - - because I don't need one. But, the challenge was there, so I did.

These parts were made using the electro-forming process described in the post below. The Radiola lamp hood was somewhat easier to make than the Neutrowound tube-shield, but still required an hour or so to cut off the flashing and attach the clips.

Above  I think that the new one is on the left.

Tabs installed on the back.

Some of these were, or have become, darker so the one above was painted to match.

While removing the nodules created on the outer surface of the form, I noticed how attractive they could be. So I salted this one (below) while the surface was still active, that is, fresh from the copper sulfate bath.

The colors on the copper nodules are easier to see in the off-focus shot below.

There was no need to do this step, but I thought it was cool.

OK, the chemistry experiment is done - at least for the moment.

UPDATE: I have added "brightener" (Mira-lax) to the bath. We'll have to see if the formation of nodules is reduced which will reduce finishing time.

If you are new to my blog - HI. If you have read a few of my posts you already know that I have a tendency to go to extreme lengths to recreate original-looking parts for my radio restorations. and, this one has been on my mind for a while now.


Below is a picture of "Number 2" the 1926 Neutrowound receiver that almost became a "parts set".

https://www.russoldradios.com/blog/number-two

Without restating the story linked above, it was a wet, nasty, rusted mess, missing all but two of the tube shields.

These radios are expensive. Parts, particularly the shields/caps are seldom for sale and when they are tend to demand a high price. Searches for after-market replacements resulted in finding a lot of interest in finding replacements with only the slightest hint that someone might have made a few - at one time.

SO, what to do?

Yep, there were 2 remaining shields/caps when I received the radio. I borrowed one for the other example, which is on display in our museum leaving this radio short 5 caps.

The restoration turned out just fine but one of the measures of value/sales price is whether the caps are missing. A radio in similar condition might be worth twice as much as one missing the caps. The only source for replacements is scavenging them from poor examples, that, while cheaper, might still cost $200 or $300. Add to that cost the long wait for such a "parts set" to become available for sale.

So, I had to find a way to make replacements. Above is an original and the first of the ones I have made.

The originals seem to be brass, formed by stamping on a dye. There are parallel marks on the sides of the originals left by this process. Then the parts are nickel plated.  A small hole is present where the part was hung on a wire in the plating solution.

It is possible that one could convince a machine shop to construct new dyes. Then stamp out original=looking parts that would to be sent to a plating shop. It would probably be cheaper to purchase one of those expensive parts-sets from E-Pay.

There has been some discussion about making parts through a process of electroforming. This can work well, with good results on small, flat parts or parts with shallow depth. Larger parts can be a problem.

I really did not expect this to work - I'll tell you why - and tell you why it did.

First, a friend, Harry, needed some 2 watt dog-bone resistors. I had never made a form/mold for these. Construction of the form is not too complicated. Making the mold - one that works, or works more than once can be a challenge. The sturdy, fairly ridged, high-temp silicon is not cheap. But since Harry was going to buy some for his project I thought that this would be a good time to try.

The red, 2-part silicone is rated at 60 on the Shore-A hardness scale, a measurement for flexible plastics. The parts must be weighed and mixed. Then, air bubbles must be removed ( a process I wish I had invested more time, but again, I really thought this would not work). Fortunately, I had a good scale and the other necessary tools. OH(!), also, I had an example from which to make the mold. Without having one of the original caps, this would have been much more difficult.

At this point I should point out the need for a plating set-up like the ones I have used in previous projects but in this case, I wasn't plating a part but, rather making one.

The inside of the silicon mold is brush-painted with graphite powder. This stuff is worse than the silicone for getting on everything. So care must be taken or your tools and the operator will be covered with the stuff. It really does a good job of making a conductive surface which, with the buss-wire conducts the negative charge to the mold.

Throw, or the ability to plate, especially into a hole, is the challenge here. For tube-people this should not be hard to visualize. The charged particles from the solution are attracted to the negative electrode. New, replacement metal moves into solution from the anode which is a copper plate. Like in a vacuum tube, the charges move most easily between the closest points of the anode and cathode. This makes throwing into the hole difficult. As you can see, copper collects on the face of the mold and the wires. Getting it into the bottom of the hole is nearly impossible without redesigning the anode.

Below, the part removed from the mold. The small specks on the surface are caused by imperfections in the mold (bubbles) but these are easily removed in the polishing process.

Removing the flashing and polishing the part prior to the last step is probably the most time consuming.

Unlike with woodworking or painting, the part must be polished PRIOR to the last finishing step. This will result in a flat, shiny surface after the nickel is applied. Some polishing can be done to the nickel but it is way to late to remove scratches or other imperfections after the nickel is applied.

Following the removal of the flashing, the part is polished in preparation for nickel plating.

I like the looks of the polished copper. It would be cool to have a radio with polished copper shields but not very original (looking).

.

Five new caps. Can you pick out the original? It is near the middle of the radio.




So - Is it likely that I will make enough of these to sell a few - NO. It just takes too long and I have radios to work on.

Do I recommend trying this yourself? Probably not. The initial investment alone for tools and materials is way too much to build JUST these - but if you already have the equipment - possibly.

Why "possibly"? Again, time and difficulty. It is hard to make this work and failures are almost certain.

BUT, now you know that it can be done.

Additional picture of inside added by request:

Plating at or above 1A per Sq. in. will plate faster but more nodules/ferns will appear on the inside and flashing.