Wireless Set No. 52 Canadian - Project

[David Dunlop]

It was very helpful that I switched over to work on the Negative Connectors Cable while waiting for the first coat of red shoe cream to set up on the positive cable. With the negative cable all cleaned up, I now had a reference point to match to regarding the overall look of both cables. I had not thought of it earlier, but there was a likely chance I could have over restored the look of the positive cable and had to try and redo it.

As it was, with the negative cable looking the way I wanted it, I rubbed back the excess polish on the positive cable and then applied a lighter second coat where needed of the red shoe cream and let it set up before a careful buffing.

Then came an application of the Neutral Boot Polish to cut the potpourri scent and help hold the arrived at red colour I wanted in the cotton loom, Yesterday, when I was giving the positive cable another buffing, it was still shedding far more colour than I liked, or expected. After thinking about it for a bit, I realized that with the wax base of the polishes in the cotton now, the only thing that could bind the colour to the cotton was a lacquer. Anything water based was not going to work at all. As it turned out, I had a can of Rust-oleum Painters Touch Flat Matte Clear Lacquer (#268390) on the shelf, so the positive cable got a light coat of that yesterday afternoon.

Checking the cable with a white cloth this morning showed the colour transfer is all but non-existent now and the outer surface of the cotton loom still looks and feels like cotton.

Next step will be to redo the cotton cording on the battery terminal ends of both cables.


David

[David Dunlop]

Today’s little adventure was to redo the cotton cording on the battery terminal ends of both Connectors Cables. I started with the negative cable as that cording had already started to unravel.

The first step was to determine the original length of the cording. This worked out well as a good shadow line had survived on both copper terminals. The length was found to be one inch. I then marked the start point for the cording on the cotton loom with a wrap of masking tape.

I did not realize the significance of the observation when I redid the negative cable cording, but a noticeable portion of the factory cotton twine appeared stuffed into the gap between the end of the cable covering and the end of the copper terminal fitting. I just assumed that had been a simple place to put the unravelling twine to keep it out of the way.

As I unwound the original twine, I came across a knot and then worked my way back down the loom to the tape. It was interesting to see how the cotton cording twine had cut into the cotton loom on the cable over time, and also how nicely the new cotton twine fit right into those grooves as I redid the cording. I did wonder, however, how I was going to deal with the gap between the covering and the terminal fitting. One often finds a wrap of the old cloth electrical tape covering such gaps but no sign of any at all in this application. So I went with what I had on hand and cut a length of twine, which I wound tightly into the gap to fill it in level as best I could, tied it off and trimmed it. I then proceeded to do the cording. The last time I had done this I was annoyed by the large spool of twine bouncing around the work desk while using it, so this time I rigged a temporary spool holder off to the side, which worked a treat! The final transition from cable to fitting was not as smooth as I had hoped but liveable. The big problem to me was the cotton twine was far too white.

Since the twine was going to get an acrylic top coat when finished, I thought I would use a bit of stale tea and brush it on to the twine to colour it up a bit. Two light coats gave it a nice light beige colour I was happy with and also helped tighten up the twine a bit as it dried. It then got a good top coat of satin Urethane finish to seal it in place.

Things got interesting when I started working on the positive cable. I found the end of the twine tucked under the battery terminal end of the twine, freed it up and started unwinding it. It unwound right passed the gap and continued on towards the marker masking tape I had placed at the starting point for this cording. When I got to the tape, at the last band of twine, it jumped back to the gap again and stopped at a knot. I was able to lift the knot just enough to cut the twine behind it and unravel the section that had been wrapped into the gap. In the second photo you can see the two pieces of original twine. The negative piece is on top and the positive one below it.

So now I realize how they dealt with the cable gap when cording these cables. They started by carefully infilling the gap tightly with twine. When they got to the top, they tied the infill off and then brought the twine down the loom to the required start point for the cording and started the wrapping process back down the cable to the battery fitting. In the process, all the twine leading to the gap, and in the gap, disappears. Armed with that newfound knowledge, I carefully duplicated the process when cording the positive cable and was quite pleased with the transition point and final look. That cording also got the tea stain treatment (coffee would probably work just as well) and the top coast of satin acrylic.

Both cables should be fully cured by tomorrow so I can reassemble the CONNECTORS, Twin, No. 17 and plug the Main 52-Set back in. I have actually missed listening to it over the last week or so.

By the way, in the last photo, no matter how I tried, the camera wanted to make the new cording look ‘camera white’. In real life, it is very much a nice cream colour.


David

[David Dunlop]

One small detail I decided to add to the Connectors Cable Assembly was a replica C-Broad Arrow Stamp to the cording at the battery terminal end of the negative cable. These markings have been on my mind for a number of years as legitimate, historical marking for Canadian Military equipment, but it has only been in the last year, or so, that I have been able to satisfy myself the markings are truly defunct and no longer in use with modern equipment. It also did not hurt to get a positive boost into working with these markings after seeing the great job Jordan Baker did with replicating the canvas cover for his FFW 15-cwt.

I have several other battery cables made by Canadian Marconi Company for use with the 52-Set, these being the short interconnection cables between the sets of two 6-Volt Wireless Batteries. They had the luxury of a rubber stamp for their work, but the ribbed surface of the cording means the stamp only reaches the outer edges of the ribs and the C-Broad Arrow is not as well defined as it would be on a flat surface. The cables I have were marked in blue ink.

Without a stamp, I had to improvise and what I discovered was Carters still makes black carbon paper for old fashioned typing copies and Staples sold packets of 12 sheets for $4.00 Cdn. So I bought a packet. I then photographed a C-Broad Arrow stamp on a piece of equipment and sized it to just over 3/8-inch diameter and printed out a copy. Taping down the negative Connectors Cable to keep it stable, I did a simple rubbing transfer to copy the mark over to the new cording on the battery terminal end of the negative cable and it turned out not too badly. A thin wipe of satin Urethane over top and it was done.

When reassembling the two cables into the Bakelite Connectors assembly it was really nice to see how easily they now slipped into place having been cleaned. The last two pictures show the restored Connectors, Twin, No. 17 reconnected to the Supply Unit and the 12 Volt DC Power Feed System.


David

[David Dunlop]

Sometimes I forget what I started out with.

I dug these two photos up of this Connectors assembly when it first arrived back in May, 2019.


David

[Harry Moon]

While I'm relatively new to radios and related equipment and probably will never make the commitment as you have I do want to pass on how impressed I am every time I check in on this thread. Inspirational.

[David Dunlop]

Thank you for the encouraging words, Harry. They are very much appreciated.

I find I am at a bit of a cross roads with the Project once again, in so far as what direction to take next. I am rapidly running out of things I can do to completion, and I hate partially starting something and then having to set it aside, particularly if it is in a state of disassembly.

When I look at the Main Set Assembly now, I know the Receiver is working, as it should. All of the problems I was aware of in the Sender have been fixed, the Heater circuit functions correctly, the Blower works and all the tuning circuits work, in that the Receiver responds as it should to any tuning adjustments made on the Sender. This latter point also transfers nicely over to the Coils, Aerial Tuning Unit. The Receiver now also responds correctly to any tuning adjustments made to the Coils Assembly.

Further work on the Coils is purely cosmetic now. It needs to be fully disassembled in order to get rid of the nasty NATO paint job it received, unfortunately inside and out, and restore the wood to the original Flat Olive Green Canadian Marconi had applied to all the wooden items they built for the 52-Set. While the guts of the Coils are out of the box, the two decals on the front panel need to be returned to originals. They are currently the late post-war stick on style with white painted printing and a white border around the perimeter. The originals were the same water slide transfer decals the rest of the set had – plain black with green phosphor luminous lettering. The paint on the Coils front panel is not original, but a close match and I would like to keep it. That will depend on how successful I end up being in removing the two current decals. The big catch here is I do not have a new enough computer to be able to create the necessary artwork for the water slide decals I need to make. So finishing the restoration of the Coils can logically be put on hold for the time being. Other than the wrong ‘look’ to it, it is in excellent shape and working exactly as it should.

That brings me to the Main Set Supply Unit. The front panels absolutely need a full restoration as a result of damage, sloppy work and incorrect decals. Once again the same decal issue, so that exterior work has to wait.

On the inside, there is lots to do and some strong logical reasons for getting it all done.

The Receiver Vibrator Supply section is working almost correctly. The mystery here is the disappearance of 2.0 Volts DC from the Low Tension circuits. I have 12.73 Volts arriving into the Supply Unit but only 10.75 shows up on the meter. Correspondingly, I should be getting +150 Volts DC High Tension out of the Vibrator Supply section for the Receiver and I am only getting between +130 and +135 Volts DC. Most, or that entire drop, is likely related to the lower than normal Low Tension feed getting to the Vibrator Supply. My current thought is there are one or more bad soldering joints along the Low Tension path that are pulling the voltage down. So I need to find and fix that problem.

Second problem I am aware of with the Supply Unit also relates to the Receiver Vibrator Supply Section.

When I undo the two Cowl Fasteners and pull the Vibrator Supply out, all that comes out is the chassis. There is a sheet metal case that fits over the entire chassis that is supposed to be removable, but it stays firmly stuck inside the Supply Unit. Not good because it needs to be out of the way to access the mounting hardware for the two Dynamotors. The two Dynamotors are my biggest concern with the entire 52-Set.

I am fortunate the two in this Supply Unit are the upgraded 1945 issue ones that solved the overheating problems of the originals. From the outside they look to be in good shape, but it is the innards that are going to need some TLC before I can even consider firing them back up. The end bearings on both need to be cleaned of 1966 grease and repacked. This is the type of grease that looks like golden honey when you scoop chunks of it out of a can fresh new, so I can only imagine what it has turned into now. Adding to the fun, the original grease is no longer made so I need to find a modern equivalent.

All the brushes on both Dynamotors also need to be carefully removed, inspected and cleaned and put back in exactly the same position as they came out. And while out, the armatures of the dynamotors need to be turned by hand and carefully cleaned. If that work is not exciting enough, I have to be able to do it knowing there are no known replacement parts for any of this stuff, should anything end up needing to be replaced. Hence my reservations at the moment about diving into the guts of the Supply Unit.

Countering all that, the ‘Plus Side’ of getting the internal work on the Supply Unit completed, will allow me to finally test the actual transmitting circuits in the Sender. I can check the individual components for effectiveness until the cows come home, but still at some point have to hit them all with high voltages and see what happens.

I will keep you all posted.


David

[Harry Moon]

at some point I do want to get the 19 set up and running, Bruce McMillan moved away from being local to somewhere in Kent England. If anybody knows of a knowledgable person near my home in Burnaby BC that would be great to know. Close to my house is relative, I think we will be able to get out on the highways once they are all rebuilt.

[David Dunlop]

I hope things get back to normal quickly for you, Harry.

Having thought about it for the last day or so, I have decided to tackle the internal issues with the Supply Unit next. I think it makes the most sense to the overall progress of the project. The outside may look scruffy for a bit longer than I would like, but the performance of the set as a whole will take a quantum leap forward.

David

[David Dunlop]

And off we go, into the unknown yet again!

I have now pulled the Supply Unit from the Carriers No. 4 and it is sitting on the bench ready for a close inspection. This Supply Unit is getting interesting already.

Overall, the interior chassis assembly is remarkably pristine. Only the top surface has accumulated any significant dirt and/or surface rust and that should all clean up fairly easily. This condition looked odd, in light of the fact the Serial Number for this Supply Unit is 5792. That is early production. The other interesting bit is the Blower Cover and Receiver Vibrator Supply Cover on the front still clearly show the factory original Gloss Navy Grey paint, The discoloured varnish top coat is only on the main Supply Unit Panel that had new decals applied during the 1966 Workshop overhaul. The only reason I can think of for the replacement of the decals is that somebody assumed they were radioactive paint. That would fit nicely with the fact the Sender panel had two decals added to it stating the paint WAS radioactive. It is not. All the more reason to be happy the decals will eventually be replaced with ones patterned after the originals down the road.


The Modification Card, still in place in its holder, has proved a gold mine of useful information, which may explain a lot of the history of this, 52-Set. Modifications 1, 2 and 4 were all performed on this Supply Unit 12 June 1966, which is consistent with the 1966 Workshop Decals added to the upper left corner of the front panel. Modifications 1 and 4 are the interesting ones.

Modification 1 was for the installation of the Modification Card Holder. This Instruction was first issued 23 May 1947, when these Card Holders were first introduced and to be applied to all active wireless equipment assemblies. That strongly suggests this Supply was sitting in original packaging from whatever build date it had until it arrived at 202 Workshop, possibly as a replacement unit for the one originally in this particular 52-Set. At 202 Workshop it was unpacked for the very first time, the two Dynamotors upgraded to the improved 1945 versions, the ‘bad decals’ replaced on the front panel and the Modification Card Holder added on the top of the chassis.

Modification 2 was a simple addition of electrical tape around the right hand terminal of resister R38A at the back of the supply to prevent possible contact with the Vibrator Supply Case when it was slid into the Supply Unit Chassis.

Modification 4 gets really interesting again. This was an extensive set of modifications required to prepare the Supply Unit for operation in conditions in the high arctic. Mostly upgrades to grease and other lubricants, but a couple of valves were also swapped out for more cold tolerant ones.

So where did this 52-Set originally come from for servicing at 202 Workshop, or, where was it going to go after completion of the overhaul work, which would have been leading towards the winter of 1966-1967?


David

[Bruce MacMillan]

Harry, check out the Burnaby Amateur Radio Club. There are a few members there that also belong to the SPARC radio museum so they speak tube language. They may be able to point you in the right direction. Sadly the three people at SPARC that worked on military sets (me included) have moved away.

[Harry Moon]

Originally Posted by Bruce MacMillan

Harry, check out the Burnaby Amateur Radio Club. There are a few members there that also belong to the SPARC radio museum so they speak tube language. They may be able to point you in the right direction. Sadly the three people at SPARC that worked on military sets (me included) have moved away.

thanks Bruce

[David Dunlop]

First off, I am stunned at how pristine the interior chassis of this Supply Unit is to look at. Photos will eventually follow.

I took some time to explore the disappearing 2.0 Volts DC from the Low Tension side and discovered absolutely nothing is wrong with this part of the Supply. Whatever I feed into it, shows up perfectly on the +12 Volt Receiver Pin on the rear Connector of the Supply. So!

I have a Main Set Receiver that reports spot on accurate voltages on its meter when fed by the Remote Receiver Supply. When in the Carriers No. 4 and fed with the Supply Unit, the 2 Volts disappears. When the Supply Unit is out of the Carriers No. 4 is shows perfect LT operation. In the Carriers No. 4, 2 Volts disappears. That points to a fault, probably a poor solder joint, in the PLUG ASSEMBLIES, Multi running along the back of the Carriers No. 4. Not exactly the nicest part to have to work on, but at least I know the Supply Unit is looking really good in that circuit.

David

[David Dunlop]

In this post, I want to simply highlight the physical damage this Supply Unit has received. None of it looks even remotely Military Service related and I suspect at least three quarters of it all took place at the same time.

The three common bits of damage are in the first three photos.

Photo 1 is a view of the top edge of the front main panel where somebody took a hammer to it, or a piece of round bar. At first glance, it looked like the work of a small diameter grinding tool, but when you look closer, you can see the effects of an impact force coming downwards and towards the front of the panel. The paint has chipped away from the front face and this impact edge is smooth. The inside edge of the panel, on the other hand has mushroomed in towards the chassis frame. Also, the force of the impact on the left most dent caught the eye screw and crimped it enough the aerial connector cable between the Receiver and Sender can no longer fir through it. Easy enough to restore the eye screw and I think it may be possible to run a simple weld bead along the edge of the panel metal at each dent and dress them down to remove any sign of the dents before I get around to refinishing the front panel. It is interesting to note just how clean the Blower Motor assembly and its related capacitor are compared to the one in the Sender last year. Even better, the dirt on this blower wipes away with a finger.

Photo 2 is the Modification Card Holder mounted to the upper chassis support plate. Note the two dents in it roughly at the midline. They look like the ball end of a hammer was active here. This holder can be removed, straightened and cleaned easily enough, and if needs be a quick zinc plating will restore if nicely.

Photo 3 is the ball end of the hammer at work on the right end of the upper rear chassis frame. Not much I can do about this damage. Most if it is right on the angle edge of the frame piece and pretty much impossible to get at. But the dirt should clean up from around it OK.

It is these three bits of damage I suspect all took place around the same time when this Supply Unit had been pulled out of the Carriers No. 4 for some reason.

Photo 4 is the last bit of physical damage that I have found that makes no sense to have happened in Military Service. It looks very much like somebody wanted to have a look inside this 5-Pin Connector. The body of the connector shows signs of being held in either a vise, or vise grips, while another set of pliers went to work attempting to pull the central core out of the connector. Clearly they did not succeed, but the connector is distorted beyond use now. Fortunately I have an NOS spare on hand I can swap out once the front panel comes off for restoration.

There are a few other physical oddities that have shown up, but I am pretty certain they are part of the Military Service History of this Supply Unit and I will cover them later.

David

[David Dunlop]

A bit of an ‘Errands Day’ today, but I have managed to remove the Vibrator Supply from the Supply Unit. A simple enough task as one just removes the two drop leads from the front clips, unlocks the two Cowl Fasteners and pulls on the handle.

In Photo 1, you can see the two side flanges of the inner sheet metal case for the chassis of the Vibrator Supply and at the back bottom, the small square cut-out in the case that allows the three banana plugs to connect with their sockets. These are the +12 Volt and Ground Input Feeds and the +150 Volts and Common Ground outputs.

In Photo 2 you have a side view of the Vibrator Supply Cover stuck in position where it blocks access to the right side upper and lower Rotary Transformer Mounting Hardware quite effectively. Note, however, the delightfully clean look of the chassis. Apart from the heavier staining/dirt at the very front and top surface of the chassis , the rest is just upper surface dust. I am being spoiled!


David

[David Dunlop]

Not actually knowing what the problem was, I probably erred excessively on the side of caution when it came to attempting to remove the Cases, Metal C1 from its tray in the Supply Unit. After carefully looking in all the usual places for signs of rust, varnish, or even soldering/welding, and finding none, I decided the best approach was to use a small block of wood against the central outer edges of the case at the exposed back of it, and start tapping with a rubber mallet.

The fist couple of taps got the Case to back out about an eighth of an inch, which was a very good sign. About 5 minutes of alternated taps from side to side eventually got the Case out until just over an inch was still in the Supply Unit. At that point, a quick, straight out tug, with hands on each side of the Case, brought it out, for what I now realize, was the first time since June 1966.

In the first photo it is now sitting free beside the Supply Unit.

The second photo shows the Case sitting on its right side with the front facing to the right of the image. You can see the slight oxidation along the lower edge of the side where it sat in its tray. Note the interesting patch mark in the upper left rear corner of the side. I did not realize the significance of this right away.

The last photo is the top of the Case, again with the front facing to the right of the image. At the back of the case, about an inch or so in, you can just see traces of a line running perpendicular to the longitudinal axis of the Case. This is a good thing. The long line running the length of the Case, and the other shorter ones, are not.

The Canadian Marconi Part Number stamped onto the top of the Case was also a surprise. This is the first time I have ever seen a CMC Part Number using a ‘Forward Slash’ between the two parts of the number. Every other CMC Part Number I have seen to date has used a ‘Dash’.


David

[David Dunlop]

The first thing I noticed once I had successfully removed the Cases, Metal C1 from the Supply Unit was a small piece of manila sheet sitting near the back of the tray the Cases rests in, with one side of the manila heavily varnished. The piece of manila is 1-3/4 inch x 2.0 inches. As I was lifting it out of the tray, I spotted a small machine screw sitting in the right, rearmost depression of four stamped into the floor of the tray, in the back half of it. These four depressions form legs, which are spot-welded to the chassis frame of the Supply Unit to secure the tray in place. This screw is a 6-32 x 3/8-inch machine screw. As I was removing it, I spotted straight away that it had come from the right rear end of the tray assembly. The back part of this tray is stamped from a thicker piece of sheet steel and forms the mounting bracket for the brown phenolic plate the holds the three Banana Sockets that accept the corresponding three Banana Plug Power Connectors from the Receiver Vibrator Supply. The sockets are designed as a loose fit on the phenolic board to allow them to easily line up with the plugs when the Vibrator Supply is slid into the Supply Unit and locked in place.

There was no sign of the hex nut or internal tooth lock washer for the loose 6-32 machine screw, and I do not recall ever finding them in the Carriers No. 4. The washer fits under the head of the screw at the front of the tray assembly, but the only way I can see to get the hex nut installed is to slide it in place in a thin was wrench, like those used for working in ignition timing points. Access is completely hidden by the right rear Supply Unit chassis angle. That ought to be fun.

Turned out the manila sheet came from the upper left side corner of the Cases, Metal C1 as seen in the photo I posted previously. It was varnished in place there to prevent any possible shorting contact between the Cases and the Negative Low Tension Brush Holder assembly of High Power Rotary Transformer MG-2A, when the Cases, Metal is in place.

Photo 1 shows the manila sheet and machine screw as found.

Photo 2 is a shot looking directly down the tray assembly from the front of the Supply Unit. It is a pretty good view of the rear phenolic panel holding the three Banana Plug Sockets and you can see the hole on the rear right end where the machine screw fell out. Also, on the tray floor at the very back you can just see the shadow in the dust where the manila sheet was resting, and the four, stamped depressions/feet for the tray can be made out just forward from that shadow.

The final Photo shows the Negative Low Tension Brush Holder of the HP Rotary Transformer, which would be at risk of shorting without the manila sheet on the left side of the Cases, Metal C1. And also in this photo is a good view of the modification to the resister terminal I mentioned earlier, where it had to be wrapped in electrical tape to better insulate it.

David

[David Dunlop]

This simple little part is similar in purpose, though slightly larger than the plates spot-welded into the upper rear sections of the Carriers No. 4 and the Cases, Remote Receiver. They all ensure adequate ground is maintained with the component chassis mounted inside each compartment.

There is probably the additional benefit for this particular Plates in the Supply Unit as it would also ensure the normally loose fitting Cases, Metal C1 that protects and shields the Receiver Vibrator Supply stays quiet and in place.

Space is extremely limited inside the Supply Unit, so as much access as possible needs to be available for servicing. Directly above where this Plates needs to be mounted on the mid-level shelf sits S-11A, the Dynamotor Input On/Off Switch relay. Canadian Marconi used the front two mounting screws for S-11A to mount the Plates. Metal Spring on the underside of the shelf. This means the open front end of the Plates now covers the rear two sets of S-11A mounting hardware, but everything is still accessible for servicing. That would not have been the case if the Plates had been spot welded in place.

In the photo, you will see a small BA screw sitting roughly between the two Plates mounting pan head screws, and to the left. I will refer back to this screw later.


David

[David Dunlop]

The mid-level shelf plays into this saga at this point so I thought I would start there with a photo of the three components mounted to it. While taking this photo, I noticed through the lens, the trace of part numbers along the face of the shelf, directly below the middle and rear components. A check of the photos Jerry Proctor posted of the 52-Set Supply Unit on his website confirmed these numbers should have been there, along with similar numbers stamped onto the side of the front component and the one directly above the middle one. Large black Roman Font with a heavy overcoat of varnish. All these had been very carefully cleaned away. Why, I wonder.

From left to right, these three components on the shelf are:

L28A, the AF Choke (Smoothing Filter) for the MG1A LP Rotary Transformer.

L26A, the RF Choke (Smoothing Filter) for the MG1A LP Rotary Transformer.

S11A, the Dynamotor Input On/Off Switch relay again.

The second photo goes back to the underside and the shelf again and the visible hardware. Note the small BA screw securing the L26A RF Choke above it. This screw, and two others in the entire Supply Unit, are the only ones I can find that still retain their factory original internal toothed Shakeproof washers. Virtually every other Shakeproof washer has been replaced with much larger thickness external toothed washers. I checked both editions of the Parts Listings for the 52-Set and these heavy-duty external toothed washers are not listed at all. They do not show up in any of the other 52-Set components either.

One might think that is no big concern, but take a look at the third photo today. I have slid the Cases, Metal C1 for the Receiver Vibrator Supply back onto its tray in the Supply unit, carefully levelled it and slid it in as far as it can go. It hits the front left hex nut securing the large L28A AF Choke on the shelf above and stops dead! That external toothed lock washer is far too thick. If you look carefully at the hole in the hex nut, you can see the end of the machine screw is set back in the threads of the hex nut. It is not flush with the face of the nut. In fact, the setback is suspiciously similar in depth as the amount of space needed for the Cases to clear the hardware completely. The only way you can get the Cases to go all the way down its tray is to apply a lot of downward force on it to flex the front section of the tray down far enough to get the leading upper edge of the Cases under the hex nut. As soon as you release that downward force, the Cases is stuck and the only way to get it all the way into the Supply Unit is to block the front of it with a piece of wood and pound it home with a mallet. Remember the big long gouge along the top of the Cases in the last photo of Post #765?

I know that the upgrade kits for the two Rotary Transformers in 1945 included new sections of wiring harness. This new harness was all done in solid colour plastic sheathed wire, as opposed to the factory original white cotton and trace style of harness. Most of the Supply Unit would have to have been disassembled to do all that replacement work and from the wiring part, it was done very well. The looms that had to be disassembled were all very neatly relaced when finished. You can see a mix of all original, all new and blended throughout the Supply Unit. What I do not understand is why they replaced all the Shakeproof washers that had a great international reputation for being very reliable electronics hardware, with these big, external toothed washers that did not fit properly, when all the original hardware was right there in front of them in the first place?!? Crazy!

Time for some Egg Nog!


David

[David Dunlop]

Here is the photo from Jerry Proctors website. It is actually the right hand side of a Supply Unit owned by Denis Chouinard.

David

[David Dunlop]

Well, it looks as if Philco Canada was not only involved with the headgear manufacturing with RCA Canada for the 52-Set, but they also had the contract to build the Vibrator Unit Power Transformer T7A (CMC 97703), ZA/CAN 4413.

Another few discoveries when I flipped the Vibrator Unit over and at first thought the interior had been horribly rusted somehow, and then realized it was actually copper plated.

Then the odd stuff showed up again.

A very careful look confirmed virtually all of the components and wiring are factory original, but every original Shakeproof washer had been removed and most replaced with those ugly, oversized external toothed washers. Some screws were even found to have had Shakeproof washers under them at one time but they were removed and replaced with nothing at all.

When you look at all the hex nut hardware, you find it was originally given a coat of varnish at the factory, but several hex nuts and open screw ends now have an additional overcoat of a thick yellow ‘paint’ that is probably some form of Loctite.

The last two photos in this Post highlight yet again the very sloppy, indifferent workmanship performed by whoever worked on this Supply Unit. The pan head screw at the very lower, right rear corner never properly meshed with both pieces of metal to pull them in together. I have experienced this phenomenon myself many times over the years. The screw threads into the first piece of metal just fine, but with not enough pressure applied to the face of the first piece of metal as the screw tried to grab the second piece, the screw just spins against the second piece but continues to thread into the first, pushing the two pieces apart. Usually you can back the screw out and apply correct pressure and try again with success. Sometimes you might have to back other screws off a bit to allow for better alignment of the two pieces of metal for the last screw. The point is, it is easily fixable. Clearly, nobody bothered here, slopped some yellow goop on the end of the screw and walked away. Adding confirmation to the indifference, about halfway forward on the same side, a bulkhead plate is mounted across the width of the assembly using the same pan head screws. As noted in the last photo, the same problem occurred with the same indifferent response. What you cannot see here because it is out of camera range is the second, upper screw showing the same effects.

So a Supply Unit component that required no component upgrades at all, was torn apart to have perfectly good hardware replaced by the wrong hardware as part of an assigned task somebody clearly did not want to do. Could have been worse I suppose, but one more reason to track down a good supply of Shakeproof washers.


David

[James D Teel II]

That sounds like it might have been a school house unit; one that was taken apart and repeatedly put back together. My own army is known for things like that.

[David Dunlop]

It certainly has that look about it, James, though I don’t think 202 Workshop was a training facility, beyond the possible monitoring of recent Trade School Graduates til they came up to speed.

I think most Canadian Military Trade Training takes place at CFB Borden, north of Toronto. Anything new arriving into Military Service that needed maintenance/servicing, would likely see examples of the equipment going to Borden early in the acquisition process so the various schools could gear up appropriate training courses. However, there are others here on MLU better qualified than I am who might be able to confirm if Wireless Maintenance was taught at Borden and if so, if they maintained a supply of the various sets up there for training purposes.

David

[David Dunlop]

I have been looking closely at the Supply Unit lately, a bit nervously at first, but the more I study it, the better idea I have for developing a logical game plan in place for restoring it. The biggest part of that plan is going to be getting all the parts and things required on hand and ready to go before I start.

The Supply Unit will have to be fully disassembled in order to get everything done. So far, that process appears to only involve unsoldering one electrical connection, to the Blower Motor mounted to the front panel. I think (subject to further study) all other soldered connections can remain intact, provided I sort out the best sequence for unbolting all the other components for removal. The most challenging bit I can see so far is the removal of the front panel. It will be captive on the two drop cords until I can move it far enough away from the chassis of the Supply Unit to access the phenolic panel terminal board all the Drop Cord wires are screwed on to, directly behind the panel.

One of the things I have needed to sort out has been the types/sizes of Shakeproof Washers used in the Supply Unit, since as I already found, very few original internal toothed washers survived the 1966 Overhaul at 202 Workshop. This has been quite a challenge.

I started by listing the Shakeproof Washers from the Hardware List for the Wireless Set No. 52, taken from the 1945 Issue of the Master Parts List. This list of washers was only 10 items long and no data references were provided at all, just a 4-digit part code that could have been Canadian Army, or Shakeproof in origin. To get more data to play with, I went to the Illustrated Parts List for the Wireless Set No. 19 Mk III Cdn and added all the Shakeproof Washers from it to my list. That gave me 20 washers overall to play with, along with their related VAOS Numbers.

The other valuable thing about the 19-Set Parts List is that it is stuffed full of exploded illustrations showing the exact relationships for all the parts, including the hardware. It took a few days, but I was able to search each diagram, find the Shakeproof Washer and link it to a specific type and size of screw, or hex nut either American Standard, or British Association. That gave me 17 bits of data for 40 possible machine screw sizes, with a grey area for shouldered screws when the washer was fitted to the shoulder and not the main shank of the screw.

For the 14 American Standard Size Gauges I could identify, it started to look like the last two digits of the Parts List Shakeproof Washer Numbers related to the Gauge Size of the Machine Screw. That led me to suspect the first two digits probably held additional useful information, but there were just too many options. So yesterday morning I decided to call in the experts at Shakeproof in Wisconsin, USA and ask if they could help. I have now received a reply back from the Shakeproof Sales Team that I was indeed on the right track.

Shakeproof did have a ‘smart number part number system’. It is geared towards the American Standard Size Gauge and the last two digits of the part number for the washers identify the machine screw size up to #12. At ‘14’ it switches to standard inch fractions, more or less logically. More on that will follow shortly.

The first two numbers on the part numbers for the washers identify the tooth pattern and the material used in the washers.

I am currently updating the spreadsheet I have created to sort this all out and when completed will post a copy of it here for future reference, and include a discussion of how the BA Machine Screws fit in.


David

[David Dunlop]

A little tiny bit pf progress over the Xmas Holiday.

I was able to find a correct washer and hex nut for the 6-32 x 3/8" machine screw that fastens PL5A to the right rear end of the tray on which the Receiver Vibrator Supply Unit mounts, so that screw, as noted in Post #766 is now complete for reinstallation. I also found my set of Ignition Wrenches, of which the 5/16" one will be needed to do that work later on.

David

[David Dunlop]

I decided to have a closer look at the two Robbins & Myers Rotary Transformers in the Supply Unit today. Not that I can do anything much with them at the moment, but more to get a better understanding of how they were assembled. A challenging task at the best of times made even more so with no surviving documentation explaining the process in detail, no detailed identification of parts and no currently known source of replacement parts.

It was the lower Rotary Transformer HP, MG2A, I decided to look at today without actually trying to remove it from the Supply Unit chassis. Since repacking the armature end bearings is one of the tasks down the road, I started by removing the end cap that was readily accessible at the back of the Supply Unit; the left end one on the transformer itself when looking at its data plate.

The end cap is a simple flat plate secured with four countersunk, slot head screws. These screws turned out to be 6-32 machine screws, in two different lengths; two of each. The shorter pair were 7/16 inch and the longer ones 9/16 inch and I carefully noted where they all came from because I have no idea at all at the moment if sizes are deliberate, or not, so best return them from where they came.

My initial impression is the end cap and the screws are all brass, but I will confirm that eventually with a magnet. With the end cap off, the next part to show up was the paper gasket keeping the Andoc-C grease in place. I did not attempt to remove it this time around in case I managed to damage it. It sure was tempting, however.

I noticed the gasket is a perfect match to the end cap in diameter and the location of the four punched screw holes. It may be the factory original gasket, or probably a factory made replacement installed in 1966. I have now added to my notes to look into whether or not this type of grease gasket paper is still available and get some in stock before exploring any further.


David

[David Dunlop]

The Rotary Transformer LP started calling my name this morning after I finished clearing the snow at the front of the house from yesterdays storm. Just as I finished, it started snowing again, so I retreated to the basement with a pail of fresh tea and headed over to the Supply Unit once more.

The end cap on the left end of the Rotary Transformer LP (MG1A), mounted on the mid-level shelf is also fully accessible from the back of the Supply Unit so I decided to open it up for a quick look and see if the four countersunk machine screws holding this end cap in place were consistent with those I found yesterday in the HP unit.

There are clearly a lot of common parts shared by these two rotary transformers. The big difference is the central body/case that is about one inch longer on the lower HP unit than on the upper LP one. Overall length of MG1A is 7.5 inches compared to 8.5 inches for MG2A below it.

When the four 6-32 machine screws came out, they were all 7/16” length, so I am still guessing why the other set in MG2A are two different sizes.

This time around, the paper gasket came off with the end cap all in one piece. The thin circle of grease at the centre of the gasket is black, holding a lot of fine dust. A careful look at the bearings inside revealed they are in Very Good Plus, or better, shape. No rust evident anywhere and no pitting. The grease, however, is a dark green colour and a typical soft grease. Not at all the thick, dark amber, homogenized honey like texture Andoc-C is noted to be in the literature I have read. So that is now added to my ‘Odd List’.


David

[David Dunlop]

After taking the time for a closer look at the bend in the lower section of the front panel of this Supply, I have decided it is not as sharp a crease as I originally thought. I am now of the opinion it can be carefully tapped out with a bit of careful hammer and dolly work.

That being decided, the next task in this project will be removing the front panel and getting said task completed. The end goal, in addition to the removal of the crease, will be a new coat of Gloss Navy Grey for the panel itself and the cast zinc Handle. This will bring these two pieces back in line with the fact they never got an overcoat of varnish at the factory as no decals were involved in their assembly on the line.

It will be a simple disassembly. Only two SEMS Self Threading Screws, just below the Handle, and the Handle itself, fasten the front panel to the chassis of the Supply Units, Vibratory.

One point of caution with the Handle on this Supply Units, Vibratory. It is meant to remove this sub-assembly from the Supply Unit of the 52-Set only. The Supply Unit is a heavy bit of work, Yes! The Handle mounted centrally on the front of the Supply Unit was designed to get the complete Supply Unit out of the Carriers No. 4. If you find you need extra leverage, it is best to undo the two Cowl Fasteners holding the Supply Units, Vibratory in place and pull it and its Case out first. Then you can reach in with your hand and grab the Supply Unit Chassis to help pull it out of the Carriers No. 4. The Supply Units, Vibratory is only held into the Supply Unit by two VERY TINY pins on the ends of the Cowl Fasteners and they are sitting inside a pair of very thin, spring steel receptacles. Those receptacles are ‘unobtainium’ at the moment.



David

[David Dunlop]

With a few errands out of the way earlier this afternoon, I settled at the workbench to remove the front panel from the Supply Units, Vibratory, No. 52, which was a straightforward task.

First item to remove was the Handle which only needed the 3/8” box end wrench from my Ignition Wrench Set to hold the hex nut behind the lower chassis while I unscrewed the Handle with my other hand.

With that out of the way, the two SEMS Screws could be removed and off came the front panel assembly. Next came removing the pair of SEMS Screws securing the two Clips, Metal, U-Shaped, 2-inch long (ZA/CAN 4576) from the upper section of the front panel. These are the two clips that hold the pair of Drop Leads for the Headgear, when not in use. They appear to be nickel-plated, so should clean up quite well. If not, then I shall be following Jordan Baker this time and brewing up a batch of nickel electroplating solution to replate them both.

The front panel now just has the two Shakeproof Cowl Fasteners still attached to it. I have a bit more research to do on them before removing them. I thought there might have been some factory markings on the back of this panel but found nothing.


David

[David Dunlop]

A little, but productive, task today.

I cleaned up the heads on the two Studs, Cowl Fasteners, Shakeproof while they were still attached to the front panel of the vibrator supply. I have been very curious about these parts for some time. I will also be asking Shakeproof about these items in the New Year to see if more answers can be found and some ideas confirmed.

In general, these Wing Head Cowl Fasteners, like their larger ‘AirLoc’ cousins, which are also used on the 52-Set, come in various stud lengths. These lengths are typically number coded and I do not as yet fully understand how that coding is based. In general, I believe the larger the number, the longer the stud length and the stud length is determined by the distance, or space the stud needs to pass through in order to have the small pin at the end of it engage and lock into its spring steel receptacle.

The 1945 Issue 1 of the Illustrated Parts Manual that Canadian Marconi created is assembled in sections and that makes it very easy to find things once you become familiar with the layout. The down side to this, however, is this manual results in a lot of repetition. Any parts used in the Receiver, will also show up in the Sender Section and the Supply Unit Section and anywhere else they were used. The 1949 Issue 2 of this manual removed all that duplication so it is a smaller size, but in some circumstances more vague to work with when trying to sort parts out. These Shakeproof Cowl Fasteners are a good example.

A pair of these Shakeproof Cowl Fasteners is used on the Receiver Vibrator Supply, and another pair on the Blower Access Door on the Sender. The two sets are different sizes.

When I was working on the Sender, I found the upper cowl Fastener was a Shakeproof 18. It locked, but the pin in it was bent in a ‘V’ towards the end of the stud and it looked like only the very tips of the pin were engaging the receptacle. The lower Cowl Fastener was not a Shakeproof product at all. It was a Dot 230, noticeably smaller and flimsier in design than the Shakeproof one. One half of its pin was broken away, but it seemed to be engaging its receptacle just fine.

When I was reassembling the Sender, I had to install new pins into the two cowl fasteners in the Blower Access Door. With them installed, I discovered the upper Shakeproof fastener did not reach its receptacle at all, the pin spun freely in front of it. Initially, the lower Dot 230 cowl fastener seemed to be working, but it was only catching one half of the pin between the receptacle and its mounting plate. So again, not the correct size on a number of levels. I then started a closer look at the 1945 Parts List. It showed that Shakeproof No. 18 Cowl Fasteners were used on the Sender Blower Access Door and Shakeproof No. 21 on the Receiver Vibrator Supply in the Supply Unit. That struck me as odd since the one No. 18 on my Sender was clearly too short. Hence my heightened curiosity about the two cowl fasteners on my Supply Unit.

It is hard to see because these items are so small, but both fasteners on the Supply Unit are Shakeproof No. 18’s, and both work perfectly. In the first photo to the left of the wing head, a classic, typewriter style lower case ‘i’ (without its dot) is stamped on the stud head. To the right is stamped an ‘8’. In the second photo, ‘SHAKEPROOF IND’ is stamped across one side of the wing head.

So my conclusion in all this is that when the 1945 Illustrated Parts List was assembled, the data for the two Studs, Cowl Fasteners, Shakeproof on the Sender and Supply Unit got reversed and the proof reading did not catch the error. Hopefully, Shakeproof may still be able to provide some information on this product regarding the size codes, and perhaps more.

David

[David Dunlop]

This part of the project was starting to raise my eyebrows and heart rate more than I felt was attractive.

Andoc-C was discontinued 15 to 20 years ago and from reading between the lines of the limited documentation on line, the main reason seemed to be that by that time, most smaller, electric high speed motors had switched to sealed bearings. If they failed and the motor died, there were no bearings to repack.

I ended up contacting ExxonMobil directly, the original makers of Andoc-C to find out what replacements they could recommend and they were very helpful.

Andoc-C (ExxonMobil refer to it as ‘Andok-C’) was discontinued without a direct replacement. It was a very firm NLGI 4 grease with a sodium complex thickener and a mineral base oil with a viscosity of 93 cSt at 40 degrees C. Based on the data I provided them for the 52-Set Dynamotors, they recommended a pair of NLGI 3 grease products that are currently available, the specifications of which come pretty close to the original Andok-C.

The first is Unirex N 3. This is a grease with a lithium complex thickener, for higher speed bearing applications as in smaller electric motors, using either roller or deep race ball bearings (as are in the two Robbins & Myers Dynamotors) and if the motor is mounted in a vertical position, the grease will not leak out the seals.

The second recommendation was Mobil Polyrex EM 103. This grease comes with a urea based thickener, a slightly narrower operating and spec range than the Unirex N 3, and is designed more for much larger, industrial electric motors. This latter focus shows up when you start pricing both greases on-line. Mobil Polyrex grease is very hard to find in quantities less than 15-kilo pails. On the other hand, the Unirex N 3 is readily available in standard grease gun cartridges.

So I am going to go with the Unirex N 3 product. The one other thing ExxonMobil commented on was I need to be sure to clean out all the old grease before repacking with either new grease. The sodium based Andok-C will not be compatible at all with either current grease as far as water/moisture is concerned.

One more step closer to being able to restore the main Supply Unit assembly.


David