The Masterpiece V receiver chassis. Note the chrome grid-cap shields on metal tubes. This radio has 5 bands with a range up to around 65mhz. It has 20 tubes counting the eye tube. There is a BFO designed for CW. The audio output is two 6L6s into what was the 18" Jensen, gone now but I am using two Jensen A12s like in the Masterpiece VI, and added a separate tweeter.

What is under all of those chromed shields? Better take a look if you are going to do a restoration - a lot of paper caps.

The underside of the chassis resembles a communications receiver such as a Hallicrafters.

Almost all of the original resistors were well within spec. This was a big contrast with the Strat chassis that I was working on simultaneously in which almost all of the carbon comp resistors were way out of spec.

The power/amp chassis is also chromed. Not quite as nice as the main chassis but still presentable.

Back side

The 2 Jensen A 12 speakers were not original equipment (according to my friend Norman B.) but were included in the exchange as was the Oxford cabinet. This cabinet is most often seen with the later 15-17 model but since all cabinets were optional, any cabinet that fits is appropriate. A note, that it has been reported that the Masterpiece V will not fit in cabinets made for the 15-17 without removing the chromed cover is puzzling since the chassis fits very well in this example.

The shelf was drilled for a pedestal mount speaker, probably also an A12. The front baffle is new and all 3 speakers are mounted to it.

The two Jensen A 12s have different FC DCR. One being about 250 ohms and the other being 5K ohms. This is good and similar to the FC values on the original Jensen Super Giant. An additional 50W 1K ohm resistor is placed inline with the two field coils which drops the B+ to just the right value and keeps the FCs from passing too much current and getting hot. A pair of Jensens with 800 ohm and 7 or 8K ohm field coils would be better but very hard to find. A pair like these is still a challenge to locate and not cheap.

I  think that the Masterpiece V is one of the best radios sold prior to WWII. Especially among those that were available to the general public (omitting some of the high tube count Scotts).

It will receive up to 65mhz, a real advantage over the Strat. This is probably a credit to the tube choices and the fact that the metal tubes were superior for RF circuits to the G type glass tubes in the Strat.

I set the 0-beat on the BFO while adjusting the IFs. It is very useful for CW signals. While the level of the BFO is not adjustable, a little careful tuning will allow SSB signals to be demodulated. This is also an option the Strat does not have.

The audio is good, really good for 1935, yet in a comparison with the 25 tube Zenith it is not quite as impressive. It does have separate bass and treble controls (tone only on the Strat) but the treble is not quite as crisp and max bass is not quite as strong as the Strat.. In this respect the 8 45 triodes with separate bass and treble interstage transformers works well for the Zenith. Keep in mind that the 18 inch Jensen would probably have helped the bass somewhat, but I am comparing apples to apples since the Zenith was stock with two A12s and a tweeter - the same configuration I am using in the MSM-V.

Tuning is always on the fast ratio until you reach the desired spot and then you can slow tune back, using the same knob. Fast and slow tuning are  separate controls or manually switched on most other radios.

There is an audio expander circuit. I'm sure it ads dome dynamic range to some music, but speech is a little weird with the volume going up and down. The expander can be switched off.

The same control will give you narrow and wide IF control. The wide IF setting would probably be used on strong broadcast stations whereas the additional 2 stages of IF selectivity are a real gain for shortwave listening.

The dial is easy to read and fairly accurate if aligned properly.

I would rather have the on of switch on either the tone or volume control but McMurdo used a separate switch mounted on the side of the cabinet.

If there is any interest, I could do a more complete comparison between the MSM V and the Zenith Strat and maybe the Scott 16 and/or the Philco 37/116 (though it is 2 year newer) and the GE M-125 (also from 1935) just for fun.

Well I couldn't wait for the tubes to get here, so I substituted some used ones in both chassis and began testing. It WORKED on the first try. Yeah, even I would not have bet on that but I'll take it.

My bench is not all that large so it take a few additional carts and such to hold all of the parts.

I did not get off with no issues though. Actually there were two.

Below you see the control/signal cable that runs between the chassis. There are three conductors that carry line voltage. Depending on the plug polarity (it is not polarized) and whether the set is on or off 120V can be on any - or 2 of the three wires. These 3 wires are twisted within the armored cable. Over years of rubbing and becoming brittle, there were many abrasions on these wires. The result could have been a short but what I saw was 120V AC on the chassis intermittently.

I knew that this cable was a problem. I had hoped that some repair to the end was going to suffice since an exact reproduction was going to be hard to produce. But now I have given into that reality.

The other issue was less significant. In the comments on the earlier Strat post below John mentioned a problem with the "Q" relay not working. Well this one - the one I rewound - didn't work either. So -

I resisted the urge to take it apart and rather measured the source voltage. It was around 300V with a short warm-up. I measured the connection to the plates of the 85 tube. It was at around 280V. So I had continuity across the relay coil and an expected voltage drop meaning that the 85 was conducting.

I then checked the grid voltage generated by the AVC tube. Something close to 0 volts allows the 85 to conduct. A signal as high as 10V will switch the 85 off, deenergising the relay. I was seeing from -.4V to about -7V. So my AVC signal was good. (when the relay is energized the closure shorts the secondary of the high frequency interstage transformer which mutes the audio until another strong signal is tuned).

So what was the issue? Checking the less than deluxe relay (see pictures in the earlier post) I found that a little nudge closed the relay. The simple solutions would be to lessen the spring tension or move the stop so that the magnetic coil was closer to the throw. I chose the latter approach and all was well.


Below is a short video after alignment. The radio is only on a short antenna so short wave reception is limited. However, when I switched on the upper band I did receive several stations, WWV and even CB transmissions. This is notable since the oscillator section of this receiver is a bit challenged above 22mhz. So I was pleased.

So this concludes the chassis restoration. Once the NIB tubes arrive (42, 5Z3 and 45s) the chassis will be reinstalled into the cabinet.

Since this project was a trade, labor less parts for a unrestored McMurdo Silver Masterpiece V, I had declined the cabinet work, instead preferring to do the fun part. The cabinet was refinished by a friend, Gary, who lives a bit north of here. The cabinet is finished, but I have only seen pictures, so far. Probably within the next two weeks you can expect to see pictures of the reassembled 1000Z.

While this project was running I was also restoring  the MPV. It is also finished - a very impressive 20 tube radio in itself. When I get some time I will post some pictures of it in the next blog.

Russ

While waiting for the arrival of the NIB replacement tubes for the Stratosphere project I have had time to work on the Atwater Kent 768Q first mentioned two posts below.

I had been lucky enough to have completed the AK 559N project a short time ago. This radio is also of that vintage with similar cabinet design as well as chassis design along with the associated common issues.

The  768Q is a 8 tube "farm" radio meaning that it was battery powered. In most circumstances, this was an effort to provide radio receivers to a large portion of the country that had yet to acquire commercial electric service in the mid 1930s.

This radio shares a cabinet with other AK models such as the AK 447. Other than the power source, significant differences between these models include  - tube count, the lack of a shadow meter and the use of a pin-type speaker using a natural magnet rather than a field coil. Most of these differences reflect the considerations that must be made to improve battery use economy. The addition of an additional tube also reflects this consideration. The 8th tube is in the audio output, the 768Q having push-pull 30s driving the speaker directly through a center tapped "magnetic" coil. This coil energizes the speaker accomplishing cone movement as compared to the voice coil in a dynamic speaker such as in the 447.

I had to use 3 separate power supplies to generate the necessary voltages. 2V for the tube filaments, 180V for the plate voltages and -22V for a C voltage (bias). I did experiment with lower plate voltages. Except for a slight decrease in volume the radio performed well down to about 135V. (decreasing the C voltage accordingly).

Above, the before and after view, noting that the cabinet had been stripped by one of the previous owners and had incurred damage including the loss of veneer as well as some structural damage.

Besides restuffing all of the capacitors and building 3 replacement resistors (note the metallic end caps of a slightly different grey/silver color) most of the rubber insulated wire was also replaced. See pile at bottom of picture above.

This chassis had survived storage very well, maybe better than any other AK of the period that I have worked on. Most of the original resistors were OK and the rubber wire was remarkably well preserved - estimating that only around 1/3 was cracked or had hardened insulation. None the less, I replaced all of the wire on the IF and RF transformers and the interstage transformer even if it appeared ok. Having the radio apart for service made replacement of the wire more practical now rather than waiting for it to fail and I did not want to take the transformers off again later. So all in all , I replace about 90% of the original rubber insulated wire with new neoprene rubber insulated wire of the same colors - or at least close.

As is often the case, the rubber insulation on the black wire was always bad and failure of other colors also tended to be similar in all examples. It seems that the pigment has something to do with the failure rate. Also degradation by mold/fungus seems to be a factor so wire that is isolated in a can or elsewhere  usually is in better shape than the mass under the chassis.

The original speaker had been removed - unplugged. It probably went to some hi-fi project, for which it would not work (well) or maybe another radio since the original owner had some interest in restoring this radio and probably had other projects as well.

Other than the cabinet being stripped/sanded, it looked like somebody had done a bit of poking around under the chassis, cutting a few wires, but nothing else.

Above: The radio in operation on the bench. Note the dial lamp. Dial lamps were often omitted from farm radios to reduce A battery consumption. It is nice that AK decided to include this option probably because it was a high end set, even for a farm radio. If the user wanted to conserve power he could have just removed the bulb.

The pin type speaker is of the same size as the original (there were two different models of speaker used in this radio). It is similar in appearance to one of the original speakers. It is not a dynamic speaker rather one that uses the lever action attached to a pin that exerts force on the cone. The "permanent" magnets are not permanent and often need repolarization. It can reproduce midrange frequencies pretty good but is very poor at reproducing low frequencies.

To make this speaker work  ,I had to remove the winding (coil) and rewind it with a center tap which goes to B+ with both ends going to the plate of one of the push-pull number 30 tubes. A number 30 is a triode similar to a 01A but with a 2 volt common cathode filament. They are efficient but don't produce a lot of audio, so using 2 in PP was a good option.

I had never noticed before that 2 of the 5 knobs have serrated edges, probably for better grip.

Above is a demonstration of the cool band selector. The 2-speed tuning is on the upper right. The knob on the lower left is a multiple position tone control and the one in the lower center is a local/distance switch.

The local distance switch is useful since it is easy to overdrive the front end increasing distortion. Testing using my AM transmitter required the switch to be in the local setting for best reproduction.

The radio has 3 SW bands with the upper band going to about 22.5 mhz. Reception on the shortwave bands is good.

The power/amp chassis is finished and while waiting for the return of the re-chromed receiver chassis I completed the restoration of the crossover network as well.

NOW the chassis is back. Really nice job on the chrome. Taking pictures of it is like taking pictures of a mirror - so forgive the reflections.

In the pictures above and below I have begun to rebuild the caps and install the new resistor kit. So the picture below is of the reinstalled new parts.

The only problem I have encountered (again) is with the small number of mounting holes that are drilled and tapped. Most of the fasteners are nut and bolt or rivets. These are not a problem. But the tapped holes must be cleaned of the new chrome and retapped. Since I prefer not to use a drill on a chrome chassis to avoid cracking or flaking the new chrome, I adapted a rat-tail file to my drill. This solution is less likely to incur those problems.

Reinstalling the parts that are riveted to the chassis is a real challenge. It takes some practice to set the rivet without cracking the fiber parts.

You just have to ignore the reflections.

Ono of the most difficult tasks in this reconstruction is the remounting of the band switch and the tuning cap.

These assemblies have a network of heavy gauge wire grounds associated with the IF section. Apparently the builders did not feel comfortable relying on chassis grounds.

Did I miss any connections?    ;-)

Trimmers and oscillator coils installed.

Moving on to rebuilding the box caps. There are 4 of these in various sizes.

While I had the boxes apart, I decided to make some replacements incase I ever needed one (pictured above).

Above is a "dry electrolytic" with a bypass resistor. From the style of resistor and cap, it appears that these might have been a factory repair since they both seem to be a year or two newer than the chassis.

Now to address the three open Candohm resistors in the center of the chassis. These are all part no. 63-407 with a value of 10K ohms rather than the values on the schematic of 10K, 5K and 5K. Since the part(s) appear to be original, I am replacing them with 10K  wire wound resistors.

There are some concerns about mounting a replacement resistor to a failed Candohm as shown above. See the video below for a solution.

I would rewind these resistors but I have not found a source for resistance wire ( nichrome or other) with values greater than about 60 ohms per foot which would require a lot of wire to get to 10K ohms.

I hid the replacement resistor for the top (stacked) Candohm below so it was far less visible - as a replacement.

Testing and alignment will begin soon.

P.S. If you find these posts interesting please LIKE or post your comments below. This is the only reason to continue posting these projects.      Thanks.

With the receiver chassis sent off to the chrome shop it's time to move on to the power/amp chassis.

Below is the sort-of before picture. Work was started on this chassis prior to my involvement. It is  shiny metal since the paint has been partially removed by wire brush. The filter caps were removed and cut open. The power/signal cable to the receiver chassis has had the connector cut off. Having done one of these before, these issues should be easy to resolve with the objective being reliable operation with an original appearance.

To repaint the chassis and parts correctly all of the iron (transformers/chokes) needs to be removed.

These are the two power transformers (large) and the two chokes.

The snap rings on the tube sockets have been removed allowing the sockets to come through the top of the chassis.

The power and signal cable going to the receiver chassis has been repaired with tape prior to being cut off of the connector. This is likely to need replacing.

OH yes! Much better.

I am going to replace parts as needed before remounting any of the iron. It is easier to work on the chassis while it is 20lbs lighter.

Replacement dog-bone resistors installed.

On this chassis these cathode resistors are 2 different sizes (watt rating). On the other chassis I restored they were all 1/2 watt.



It is time to start on the filter caps.

These were all early electrolytics. The design seems to be Sprague's attempt to copy and improve on the Mershon "wet" electrolytic can. There seems to be two or more versions used in the 1000Z. First, a solid copper can with a ground  (-) lug incorporated into the isolated base. Then an evolution to the more common aluminum can without a ground lug. The ground lug is accommodated by an additional hole drilled in to the chassis. This extra hole is seen in all of the first 254 power/amp chassis BUT may have been deleted in some of the last 100 chassis produced. The RF/receiver chassis does not have these extra ground lug holes rather using the later version mounting system.

Above: The first filter.
As you can see on the can, It is rated at 600V and 4uf.

The 600V rating poses a challenge for most electrolytic capacitors (even this one failed explosively). Knowing the compromises involved in using electrolytic caps in this position, I chose to use Solen  metalized polypropylene instead. These, too, have some disadvantages, size being the most significant. They are, however, rated at 630 volts. I have been using these in place of electrolytics in all applications where they will fit for many years now and have not had a single failure. I anticipate a much longer life as compared to electrolytic caps especially when the electrolytic caps are being operated near their upper voltage rating. An additional advantage is not having to worry about polarity (electrolytic caps are polarized). The other significant disadvantage is cost. The Solens cost about 10 times what a 450V electrolytic cap costs.

The objective in rebuilding these cans is to exceed as much as possible the original voltage rating and to STUFF as much capacity into the can as possible - within the original spec narrowed to about -10% to +150%. So, This 4uf 600V cap is now rated for 6uf 630V (tested).

The larger value filter caps are more of a problem. They have slightly less volume since they were rated for 450V. (The volume of a can is generally larger as the uf rating or the V rating increases. In these caps the 600V rating increases the size more significantly than the lower uf rating decreases it. In other words, the 4uf @ 600V can is slightly larger than the 16uf @ 450V can).


Below: the ground/lug isolation base for the early caps, showing the lead that penetrates the chassis through the 2nd hole. This configuration is not unique to early 1930s radios but this particular part with the dished edges seems unique to the 1000Z.

I did not disassemble these cap cans. I would have done it slightly differently, but, working with what I had - the replacement cap is attached to the + lug with a tapped screw treated with Never Seize (RT).

On the copper can, a ground connection is easily made to the can its self. On the Aluminum cans, I feel safest in extending a ground from within the can to the mounting hardware - not trusting an aluminum solder joint. (See picture 2 above)

To accommodate the method in which these were disassembled, the can sections are rejoined with solder. Heat must be controlled since there is a new cap inside and excessive heating will destroy it.

On the can below, I cleaned up the joint and plated the solder with copper. If this was the more common unpainted version it would be finished.

These caps were originally painted black. So the repair needs to be painted.

Do not paint the lower edge/crimp on the can. It needs to make electrical contact with the mounting hardware.

I feel, that if at all possible, the original text (value/part number) should be preserved.

The cap above is now rated for 20uf @ 630V.

Yeah, I painted my thumb too. Nice!  ;-)

With all of the parts rebuilt, tested, disassembled, painted and reassembled I was able to put the amp back together.

I have decided to rebuild the cable that links the two chassis rather than risk it shorting out.

I have accepted another Strat restoration project.

This radio belongs to Jeff, a long time local collector. He would like the chassis to remain as original in appearance as possible while still functioning like new. (Not too big of a challenge).

I believe this restoration to be critical in preserving the history of one of these iconic examples of American innovation and industrial prowess in the early years of radio. For this, I have made an exception to the "no outside projects" statement on the home page.

SO, here we go - -
This restoration may seem a little slow since I can only spend a short time over the bench on any day - getting old is a PTA, but this gives me time to accurately update this blog.

The 1000Z has 2 major chassis, The RF chassis (above) and the Power Supply/Audio Amp chassis. Additionally, the output/crossover chassis has some critical, custom, parts that must be serviced.

I have begun work on the receiver (RF) chassis and will post updates as the project progresses.

HOLD it right there - Well, after a closer examination, we have decided to replate (chrome) the receiver chassis. This is a huge amount of additional work, but it would be a shame to have the restored chassis looking like this:

Today, the documentation and removal of ALL of the components from the chassis has begun.

The dog-bone replacement resistor kit for this chassis is finished.

Updated pictures as the chassis is stripped of all parts -

Very few issues have ben found so far - which is nice.
One of the filter caps has blown the top off - will have to fix or find replacement.
The relay that enables/disables the audio in the muting circuit has an open coil (just like on mine and I suspect many others). It will be rewound.
A few of the original "paper" caps have been replaced - I will use the artwork created in the earlier restoration to build correct-looking replacements.
Chrome - as noted above.

Further deconstruction and testing reviled an issue with one of the interstage transformers.

Portion of the schematic form Nostalgia Air showing the relationship of the 2 interstage transformers
Note that two 76s drive two 42s  driving eight 45s (not shown).


Below, the deconstruction process continues.

The tube sockets are secured by a snap ring. This means that the sockets must be unwired before they can be removed from the chassis through the top.

These are the Bradley volume and tone controls. The volume control includes a section for base contour (loudness) that increases the bass level as volume decreases and decrease base as volume increases until about 3/4 volume. At this point the base boost is nil but still controllable by the tone control.

I have not seen these exact units in any other radio. It would be fair to say that replacements would be very valuable. There is no indication that these are damaged.

The trip lever on the shaft of the volume control is used to switch the radio on/off. Needing to switch 350W, I believe that a suitable combined volume on/off switch was not available.

Resistor kit for the receiver chassis below. Even though some of the original dog-bone resistors were 1/4 W the replacements are no smaller than 1W, mostly 2 & 3 W (regardless of size).

Below are pictures of the variable bandwidth IF transformers and a video showing the mechanics of their operation. Wider IF bandwidth allows the radio to detect more of  the modulation resulting in  better fidelity which is quite noticeable in the treble range. The drawback is worse adjacent channel rejection. You might also notice that a signal is slightly stronger when the IF is set to wide.

Only things left now are the tuning cap and band switch. I had left the shield on to protect the cap, but it can come off now.

The deconstruction is done. I can work on repairing the defective parts and on the power/amp chassis while the main chassis is off to the chrome shop.

Band switch and tuning cap removed.

Needed to drill out a few rivets. Above, fiber guides for the variable IF adjustment shaft. AND - NO, I didn't drill out the holes to the right. This seems to be factory. Maybe they needed to enlarge the holes after the original plating process.

Receiver chassis all ready to go off to the plater's.

QAVC relay, still needs to have the coil rewound.

Here is the QAVC relay with it's new coil.

At this point, I am going to begin work on the power/amp section and will start a new blog entry.

We had been helping sort out a collection of radios and memorabilia. Last weekend there was a sale with the proceeds to benefit OPB/Holly Theater Restoration. What is a better excuse to buy old radios than to help out a charity? Anyway it sounded good to me.

There were hundreds of items. Mostly old periodicals and the promotional trinkets and such referred to as "premiums". The sale started at 10AM which was when we got there. There were already a dozen or more people going over the tables. Since I had priced out most of the sale items there was no need  to browse. I already knew that the only things I was interested in were a little battery radio in a leatherette cabinet and a Magnavox R3 horn.

There is little information on radios sold by Wurlitzer prior to joining up with All American and Mohawk followed by the marketing of products under the name Lyric.  Since this arrangement was established in 1927 and this radio uses UV 199 tubes vintage 1923/24, it is likely to have predated Lyric.  It is still likely that it was built by All American. It is probably one of the first radios to have been sold by Wurlitzer.

In the video above the radio is driving an RCA 100B cone speaker with plenty of audio on the local stations. I was running the UV 199 filaments at about 2.9V.




The following is from a post on ARF:

Russ, it's odd that you brought this up. I've been looking into early Wurlitzer radios recently and have documented quite a few. I don't know who made your set yet, but I had a Deforest with a similar leatherette finish once. Wurlitzer had 20 stores in Chicago during the mid 20's. I'm uncertain how many stores they had in total, but it must have approached 100 or so. They advertised "coast to coast" in their ad copy. They were like the Best Buy of the 1920's and 30's and must have sold a lot of radios. They were big enough they very well might have sold different private labeled models in different regions of the country depending on what deals came along.

I have identified these mfgrs making Wurlitzer branded radios beginning about 1925:
Apex Super Five
Buckingham Radio
Mohawk Corp of Illinois

Apex was likely a one time deal due to the massive over production of the Super Five.

Buckingham never made any of their own cabinets. They made radio chassis only and promoted private label business to large retailers, dept stores, auto stores, etc so their models might be found in numerous cabinets depending on how the end customer chose to market the set. They went bankrupt in 1930. The little info I have on the early Buckingham branded sets suggests Wurlitzer made the cabinets. I am developing a history on Buckingham that I will update soon at the Radiomuseum. Buckingham's president was an interesting character. He found himself locked up overnight at the Cook County jail on two different occasions.

It's a shame Mohawk merged with Rauland because it distorts the history. Mohawk and All American should be evaluated at the time the set was made and what label it carries because these were two completely independent companies for most of their existence. I hear people calling All American sets Mohawk and vice versa which drives me nuts .

Wurlitzer sold Mohawk radios under both the Mohawk brand and also under the Wurlitzer brand. Some of the 1927-28 models were made with a completely different escutcheon plate instead of the traditional arrowhead. The knob layouts were the same. This was done no doubt to disguise them from the models being sold by Mohawk's independent dealers. Mohawk like Buckingham sold both under their own name to a dealer network and also took on private label business at least for Wurlitzer and as I've already mentioned I believe both companies relied on Wurlitzer to supply their cabinets. Mohawk made horizontal mounted exposed tube phonograph radio units for Wurlitzer and others. I'm 100% convinced Chieftan was Mohawk's attempt to dump their remaining inventory of 1st generation one-dial phonograph radio units. Chieftan was listed in one of the radio publications as being located at Diversey and the bridge. That is the exact location of where the Mohawk factory was. Alan D once argued with me that Chieftan wasn't the same, but he was wrong and I didn't know what I do today. Mohawk introduced a 6 tube "H" layout horizontal mounted exposed tube phono set that was offered in Wurlitzer's phono combo console units. This new 6 tube model would have obsoleted their old stock of phono units so I believe they made up some "Chieftan" labels and got rid of them that way. BTW, there is a Chieftan set on ebay currently. I don't want to cause any trouble with ebay sellers, but that radio has had some serious cabinet modifications.

Matt

The AK 559N is a 9 tube radio with an RF amp and a signal meter. Push pull 2A5s provide audio power to a single 10.5" field coil speaker. The cabinet is small by 1930s standards.

Earlier I had said that I had reached the bottom of the radio pile given to my by Jerry. Well, that was true. Of the 40 or so radios several were in such bad shape that restoration was either going to be nearly impossible or very time consuming. Several of the early AC powered "bread box" radios had both poor cabinets and failing pot-metal parts. There are some models where failure of the pot-metal castings is so common that it is unlikely that a good replacement could ever be found. These radios may still be desirable for display but if the cabinets are shot then there is no really good reason to work on them.

Some of Jerry's radios had the unfortunate luck of being exposed to moisture when a fir tree limb punctured the roof of his two-story shop. I believe that this AK 559N was among them.

As you can see from the BEFORE picture (above left) there was significant damage to the cabinet. This added to the fact that restoration of most 1934 Atwater Kent chassis is always a big job pushed this project towards the parts pile. But I also knew how nice it could be.

Anyone visiting the shop/museum has seen the "wood shed". Not used for fire wood (mostly), rather for wood and veneers used in cabinet repair and for parts chassis. The shed keeps the clutter down in the shop. There is room in the shed to keep a couple of cabinets. I usually decide right away if there is a future for most radios but sometimes a radio like the 559 gets disassembled, the speaker/chassis stored and the cabinet placed in this area. If it gets in the way, well, at least the veneer is salvaged. But sometimes (seldom) there will be a break in the demands of shop/house/tree farm and the project will be revived.

These AK chassis are outstanding for a mid-rage radio manufacture of the mid 1930s. I think that they attempted to use very good parts in the assemblies. I doubt that any consideration was given to the ability to survive a century. We are lucky that some have survived - more or less.

I really was not looking forward to working on the delaminated cabinet so I started on the chassis restoration, a good project for the cold winter months.

Above is the before and after shot of the underside of the 559 chassis. As always the objective was to repair damage/deterioration and find/replace missing original parts. The result should look like the chassis did a year or two after manufacture. (to look new most of these chassis would need to be replated, something that is done for high-end radios)

Unfortunately nearly every part and wire needed some restoration or replacement.

I usually move through a chassis like this servicing or replacing all of the parts hooked to a lug at one time. Often this will result in a lot of parts being pulled out at once. I have a good memory and schematics help a lot but it is highly advisable to take a lot of pictures before and during the process. Most radios work upon completion. Once in a while there will be a miss-wired connection but this is so seldom that upon completion I just plug the radio in and begin alignment.

This radio has a modular RF/IF section. Since all of the wire and most of the components needed to be serviced or replaced this sub-chassis must be removed.

Above is the before and after of the rf/if chassis. At this point someone should ask if I know where all of those wires go.

In addition to the point to point wiring all of the RF, IF, Power and audio transformers need to be rewired. This also includes the filter chokes in the power supply. AK liked to put tar all over most coils and windings (potted). The connections need to be located inside of the cans and housings so that all new "rubber" wire can be added.

Above is the original wire. Some techs look at this and say that this wire is serviceable. Well some of it isn't. and one day soon, none of it will be. I have never had an AK power transformer fail after it has been rewired. I believe that the general consensus that they are "weak" is derived from the likelihood that shorted rubber wire is involved in the failures.

Above is a "restuffed" AK paper capacitor. It is tough to preserve the rather flimsy paper label and barrel along with the leads that exit through the side, rather than the ends. AK did not make it any easier for the restorer/tech having used a part number rather than a value on the label. For this a schematic/parts list is necessary to assure the proper replacement.

Resistors in the chassis are a real problem. For the most part, they are all bad. To make things worse for the restoration, the construction does not lend it's self to easy reproduction/replacement.

The styles of resistors used are either an early "dog-bone" or various wire wound types. In many radios the wire wound resistors, built on some form of substrate, have survived. AK built their WW resistors in the form of a flexible attachment that looks like a heavy gauge wire (right above). Many of these have not survived or have become intermittent. Unlike the types built with visible wire these corrode badly.

The dog-bone style types rely on a carbon rod inside of a ceramic holder with lead ends that make a mechanical contact with the carbon rod. This connection becomes intermittent over time.

The two examples above have been rebuilt. In the case of the WW resistor 4 or 5W modern resistors are hidden in the ends - usually in both ends - and the original cloth cover is slipped over a new wire connected to the new components. The old dog bones need to be drilled. A hole in the center of both ends allows the carbon rod and the ceramic to be driven out of the end. Care must be exercised so as to not damage the soft metal ends. A new 2 or 3 W resistor is covered with high temp spaghetti and soldered to the ends.

The AK all wave is what most collectors call a robot dial or shutter dial (as with Zenith). The dial displays slide up and down allowing only the selected band to be displayed. There is also a shadow meter used to display signal strength. These shadow meters often become less sensitive due to  depolarization of the needle (movement).

Well, with the chassis completed I needed to roundup my glue and brushes. While the grill cloth is intact, the baffle board it is mounted on is just a pile of delaminated plywood.

Most of the veneers is still present though much of it is loose.

Here we have a piece of elm burl that can be used for replacement (not bird's eye maple).

Above is the brother of the 559, the 7 tube 447 table model. It's construction is very similar as are is the veneers used in the cabinet.

I'm glad the 559 did not become spare parts.

This is the last of the radios given to me by Jerry: See posts below.

In 1928 Sparton (Sparks Withington) was still at odds with RCA over radio pattents. Without rehashing information that can be found elsewhere: http://spartonequasonne.webs.com/models.htm
I will give you some breif highlights of this Equasonne version.

First, I consider it a true Equasonne and by that I mean that it does not incorporate the RF stage added to later units - which really was an attempt to improve on the shortcommings of the Equasonne design and really was consideration for the possible infringement of the TRF design that Sparks was trying to skirt. And it also lacked the first AF stage that was added to some models, like my 930 (mentioned on the web page above). This modification basicly added a 484 or 485 triode to boost input to the audio final(s).

On this note it is important to consider the tubes that were used in these radios. Again, trying to dodge RCAs pattents, Sparks used their own tubes which were really only slightly different than RCA's with the significant difference being filament voltages.

So the 69 is an AC powered table-top radio, very similar or exactly like the chassis used in consoles. This makes the chassis a tight fit. Especially when you consider how the modules are connected.

There are 3 basic modules in all Equasonnes with the rare addition of the audio stage mentioned above. In the back is the power supply/audio amp, front left, the passive tuner (no RF amplification) and then, on the front right, the RF/detector module.

As mentioned, and a serious consideration prior to undertaking any sparton Equasonne restoration is the fact that the cost of the radio is little compaired to the cost of the stock, Sparton/Cordon tubes. This version uses a Sparton 585 as the only audio stage following the detector. Now, for all practical pourposes a 585 is the same as a 250 which only slightly improves on the chances/cost of finding one if yours is missing. The other triodes are 485 (or 484s) which were easy to find and cheap but that is changing too. For practical pourposes a 56 can be used, NOT a 27, though this can affect the tuning of the already finicky RF stage. Read more on the site above on Sparton's suggestion for strong or weak tube placement.

The most significant issure with this radio, other than the fact that all of the tubes were missing or wrong (27s), was the failure of the power transformer. At some time three of the 484s were replaced with 27s. This could have lead to, or at least contributed to the failure. Anyway one half of the HV winding was shorted.

I found a replacement on E-Blah. It had the same problem. The nice fellow refunded it;s cost. Having two inspired me to attempt a rewind. Replacements are few since the wierd filament voltages, 5, 7.5 and 3 are not standard on any other manufacture's radios.

The transformer I got off of the auction site had been heated so much that the windings has seperated since the tar and bee's wax had all melted out. It was easy to remove the HV from the center of the stack, inspect the primary and filament windings and then replace the HV with one I made. Well I measured the wire size and ohmed out the good side of the center tapped HV winding and got 324 ohms. A little consultation of the magnet wire chart got me going on a new one. This worked BUT I must have misjudged the wire size by one gague and ended up with a 450-0-450 volt B+ winding.

It would have worked. It needed about a 16k resistor but at about 50W - really big! So I moved on to the original transformer, knowing now what I did wrong. To make it a short story, I was sucessfull, though this one required some time in the oven to take apart. It was now at 325-0-325 volts for the HV prior to loading.

I could now move on to recaping the unit.

The biggest challenge in recaping the RF section is the odd construction of the original capicators and as usual, I wanted to keep the factory look. In the photo - 2 above - you see the tubular like things on the RF board. All but one of them is a 1uf cap. On the Equasonne page listed above he has a process that can be used. It was adapted for restuffing because a single replacement cap would not fit inside of the original.

I found that it was much easier to use two .47uf caps allowing me to leave the support rod intact. This also made the part much sturdier.

Fortunatly all of the other "iron" was still good.

There is one other thing I should mention for all Equasonnes, especially this model. That is the grounding of the modules which most might assume is accomplished by the multiconductor cable - but no!

Above is sparton's ground system for later Equasonne models which was not used on the 69.

On this radio the most convenient way to ground all three modules togeather (required) is to strap them togeather at the mounting bolts.

Though there were reminents of this type of connection prior to disassembly, I can't be sure that this is what the factory did - but I think that it is correct.

The design of the cabinet keeps these bolts and wire off of the table top. So unless something is dragged across the bottom the ground is rather safe. Opperation of the unit whithout this ground results in motorboating and other undesireable noises.

In conclusion, I find this radio to be an average/acceptable performer. Considering the design it is acctually superior to what you might expect and better than most of the 5 tube screen-grid models that drive a 245 by resistance coupling to the 224 detector.