Wireless Set No. 52 Canadian - Project

[David Dunlop]

After thinking about the repair process for the damaged Headgear Assemblies Type 10 for a while, the task began to make less and less sense, in regards to salvaging/repairing the cut Receiver Lead. Apart from not having any equivalent terminals for the original brass staple terminals that had been cut off, more importantly, I would have to trim back that lead a good inch or more to get enough free wire from the two conductors with which to work. That whole process would have ended up pulling the entire cord assembly off to one side of the headgear, which would have looked very odd. So I felt a bit bummed for a while until I remembered finding an NOS headgear cord many years ago at a flea market. A half-hour of foraging through boxes and bins and I found it.

And what a nice surprise! It turned out to be a complete replacement cord assembly for the Type 10 Headgear and the loom was a perfect colour match for the two drop cords on the Main Set Supply Unit.

The other Type 10 Headgear Assemblies I have will become my spare. It has a lighter colour loom, very close in appearance to standard wartime 1937 Pattern webbing. So this is starting to work out rather nicely. The service photos I have seen of the 52-Set, wartime and postwar, all show the single Operator’s headgear connected to the right drop cord on the Supply Unit. I suspect the Cypher Clerk took advantage of the speaker in the 52-Set Receiver to monitor traffic for coding purposes. Most photos show the left drop cord connected to a Jumper Cable feeding over to a Wireless Remote Control Unit No. 1 and from there, probably off to a Land Line connection. If the left cord is not in use in this manner, it is sitting empty on its Supply Unit clip.

The first two photos today show the complete NOS CORDS and a close-up of the terminal fittings. The microphone fittings are at the top – the small brass ring terminals. The two receiver leads are below showing the plain brass staple end terminals.

The second photo also nicely details the larger brass crimp that secures the end of the cotton loom from moving, or unravelling. The outer end of this particular crimp has a loop pressed into it and you will see a small S-Ring fitted to each of these loops. This is the Anti-Strain that takes the weight load of the entire headgear assembly off the electrical terminals on the receivers and transfers it to the Bakelite body of the receivers themselves. More on this in a later Post.

The third photo illustrates the Grip & Clamp Assemblies fitted at the main wiring junction of the CORDS. I always assumed this assembly contained all the terminal connections between the Y-Plug, microphone and receivers. Turns out it is merely a two-piece fitting that fits over the pre-existing junction already woven into the CORDS loom.

The two parts of this item are PLATES, Phenolic, Front & Back, Grip & Clamp Assemblies. Front – ZA/CAN 5244, and Back – ZA/CAN 5245. The two parts are held together by four sets of brass hardware (screws, flat washers and internal toothed lock washers). ANC, Brass, RH, 4-40 x ½ inch.

The back of the Grip & Clamp Assemblies has a large spring clip fitted to it. The Operator uses this to attach the CORDS to the front flap of his Battle Blouse in order to take the weight of the entire headgear assembly off his neck.


David

[David Dunlop]

When RCA Canada developed the Headgear Assemblies, Cdn, Type 10 for the Wireless Set No. 52, they incorporated the pre-existing Receivers, Watch, MC 50-Ohm (ZA/CAN 0842), which had been used on some of the headgear made for the Wireless Set No. 19. They did so, however, with a couple of interesting changes.

They took advantage of the push in connection feature of these receivers, rather than using the terminal screws to mount into ring terminals on the leads. This may have solved a couple of related problems in the field. The screws no longer have to be completely removed to replace a defective Receivers Watch MC, so the screws are less likely to be lost. Additionally, placing the lead connections inside the Receivers, Watch MC gets them out of the way of excessive moisture/rain, which may have been causing difficulties.

The second change RCA made was in adopting the small metal S-Rings for the Anti-Strain devices on the Receivers, Watch MC. On the Wireless Set No. 19 headgear using the Receivers, Watch MC, a smaller metal crimp clip was used to secure the loom on the Cord up by the Receiver leads. Woven into the loom at these two ends was a length of what looks very much like a length of thin, brown or black, shoelace. When the Cord is fitted to the Receivers, this lace is looped through the Bakelite Anti-Strain loop cast into the side of the Receivers below the terminals and then woven around the leads to transfer the weight of the Cord off the terminal connections. The excess lace is then trimmed away leaving a telltale little stub about ½-inch long sticking out.

The first photo posted today shows the broken connection on the Type 10 Headgear I have to replace. The S-Ring is still in place on the receiver loop. The second photo is of a headgear assembly from a Wireless Set No. 19, using the same Receivers, Watch MC. You can clearly see the brown Anti-Strain lace woven around the connections. It is possible these cotton lace Anti-Strains were subject to rot, and subsequent failure, so RCA went with the metal S-Rings.

Also worth noting in the second photo is the massive amount of red lacquer used to cover the two terminal screws. Very little is evident in the first photo where the connections are now inside the Receivers, Watch MC.


David

[James D Teel II]

I’m very interested in how your restoration of the No.10 headset works out for you. I have a virtually NOS No.10 that I use to listen on my 19 set, but it won’t transmit. I think I probably still just have a series of bad voicemitters because the set keys up when I hit the pressel switch, but I get no side tone.

[David Dunlop]

Hi James.

What colour is the Mouthpiece, Rubber No. 2 on your NOS Type 10 Headgear?

In the 52-Set Manual, the one photo of this headgear shows a white rubber mouthpiece. On the other hand, virtually all illustrations indicate the colour as black. The descriptions in all the 52-Set and 19-Set Parts Lists make no mention of colour at all.

My two NOS Type 10 Mouthpieces are both equipped with black rubber mouthpieces. I actually have a white rubber mouthpiece, but oddly enough it is fitted to a No. 7 Handset on an American made 19-Set Headgear Assembly and although still quite supple, it has developed a number of ring cracks just about the Bakelite lip on the mic cover it fits over. So I am not too keen to try removing it.

I am curious why white rubber was used for some of these mouthpieces unless somebody thought it might make the mic easier to find in the dark.


David

[James D Teel II]

David,

It’s black.

[David Dunlop]

I should have had my cataract surgery done BEFORE I started this project three years ago!

I say that as a preamble to I correction I must now make to a comment in Post #705, where I said my second set of Type 10 Headgear was a lighter coloured loom than the one I am restoring. Having dug it out this morning to examine, I find both headgear will be the same colour when completed and will match the two Drop Cords on the Main Set Supply Unit perfectly. Photos attached.

The plan is to use this complete headgear to map out all the connections correctly to make life easier when restoring the damaged headgear. Turns out it was a good thing I decided to do this.

Somewhere in its lifetime, a previous owner of this Type 10 Headgear made the same incorrect assumption about the headset straps on the Receivers as I had done back in the 1980’s when starting to learn about the Wireless Set No. 19 equipment.

At first glance, I had assumed the solid metal headset strap with the black padding went over the top of one’s head and the canvas strap wrapped around the back of your neck. I learned very quickly that by doing that, it is impossible to get the two receivers centred properly over ones ears. There is no vertical height adjustment available. A good friend sorted me out on that problem. I have now discovered somebody had the same wrong assumption and switched the bands around on this Type 10 Headgear. Once might be able to get away with that error with the Type 10 because in employs oval ear cushions rather than round ones so there is a slight height fudge factor present in them. Whoever designed the oval cushions, however, must have been aware of this problem in the field because the word ‘TOP’ is cast into one end of the oval. If all the parts of the headset are assembled correctly, the ‘TOP’ does indeed indicate the top of the entire headset assembly, not just the cushion and the harness leads end up at the bottom of the two receivers. Also, the left receiver lead ends up on the left side of the Grip & Clamp Assembly and the right receiver lead on the right side of the Grip & Clamp Assembly, with the larger Microphone lead in the middle.


David

[David Dunlop]

I now have two complete RCA Type 10 Headgear Sets that are once again fully working, to put towards the 52-Set Project.

It only took nine days, five sets of headgear and a pile of NOS parts to accomplish this, along with a very elevated amount of muttering. I am still unwinding from it all, but both sets are now correct for the 52-Set, from the RCA stamps on the 5-Pin Sockets and Microphone Cases up to the ‘Philco’ stamped receivers RCA used in their production.

I have the backstory behind this bit of work to sort out yet, along with supporting photographs and will post them up as soon as possible.


David