Wireless Set No. 52 Canadian - Project

[David Dunlop]

A nice, hard, flat work surface with a 90-degree front edge can be your best friend when trying to remove the Holders assembly from the Microphone Case. Over the years, fine dust infiltrates the case and finds its way into the two grooves either side of the Holder that slot over the two side ridges in the case. Just enough to make it tricky to get the Holders free and out.

If you turn the Case upside down and hold it at the Spring Contacts end, you can give it a few good, flat whacks on the surface of your work surface and watch the Holders at the slots to see it slowly sliding up on the ridges. Eventually, you can carefully pinch the outer edges of the two Contact Spring assemblies with one hand, and hook a finger of the other hand under the Microphone Cord by the Grommet and gently lever the Holders out of the Microphone Case to work on. With this first Headgear Type 10, I was not so lucky. First off, as noted earlier, the Inset was stuck in the Holder making it difficult to access the Holder itself. The same whacking technique eventually paid off, however. The Insert slowly started to move up in the Holder and the Holder up in the Case. I was eventually able to grab the top rim of the Insert with one hand and pull up on it while pressing the top rim of the Holder back down with the other hand, and the Insert pulled free. Then I could repeat the whacking to release the Holder assembly.

To get access to the terminal posts for the wiring along the top of the Holder you have to separate the upper Holder piece from its Lower Plates. The first step in this process is to remove the two wires connected to the Upper Holder at Positions 1 (single black trace) and 7 (single red trace). Position 1 is just a Terminal Screw and lock washer. Undoing the Terminal Screw at Position 7, however, also releases the Contract Spring for the Insert Case mounted at that location. Don’t lose it.

Then you can turn the Holders assembly over and remove the two RH Screws top and bottom that hold the two parts of the assembly together. The Holder can then be lifted away from the wiring. This time, as you can, see in the photos, the Holder came away in two parts, so I had to dig out a complete replacement Holder assembly. That was annoying enough, but the real mystery was finding a Jumper Wire running from Terminal 1 up to Terminal 4, for the Relay. That made no sense as it would turn the Relay Circuit permanently on, which was what was happening with this particular Headgear. Note in the third photo, this Jumper Wire is typical white loomed with a red/black tracer, typical of 19-Set and 52-Set production.

This discovery meant I had to open up the other Headgear Type 10, that was working just fine, and see what was going on inside it. In the last two photos, you can see this particular Jumper Cable was a solid black plastic loom, more typical of late war production. This Jumper Wire connected Terminal 1 to Terminal 3, which made much more sense and actually resulted in a fully working Headgear assembly. So when I started transferring the wiring from the broken Holder to the new replacement, the Jumper Wire was repositioned to Terminal 3 at its top end. That process was started in the third photo today, with the clear view of the Jumper Wire.


David

[David Dunlop]

If you look back at the second last photo in Post #715, you will see a good view of the upper backs of the two Contact Spring Assemblies in what I am referring to as the later version of the Type 10 Headgear. Notice the complete lack of rubber pads on the upper ends of the back of the Contacts. That initially puzzled me until I spotted the upper rim of the Insert. It had a half inch wide by 1 and a half inch long piece of black plastic hanging from it, that was originally centred behind the two Contacts. When I lifted the Insert out, this plastic strip fell away completely. The Insert in the broken Holder from the ‘Earlier’ headgear with the black rubber squares showed no sign of a plastic strip ever being applied to it.

I tested all the Inserts I had on hand and found the range of resistances between the centre terminal on the bottom and the case was from 42 to 47 Ohms and they all seemed in good working order. As I noted in an earlier Post, the Insert should be a snug fit in and out of the Holders, with just enough resistance from the two case Contacts on the sides of the Holders that the Insert does not wiggle and the bottom Contact Spring resistance will still push the Insert up a bit in the Holder. There should be no wiggle laterally. If there is enough wiggle, or an Operator thinks the backs of the two vertical Contacts must touch the case of the Insert for some reason, the Insert will fail to respond, as it should when the Pressel Button is pushed down. The Insert will probably appear dead.

If the fit of the Insert in the Holders is too snug, as I discovered in mine, a whole new problem develops. When the Insert is forced down into the Holders, it will transfer a load through the side Contact Springs into the Bakelite body of the Holders. If the Microphone gets banged around or dropped, that shock will transfer directly to the Bakelite and crack it. When I looked at the crack on mine, it was full through with rust dust, so had been broken for a long time.

When I had the Side Contact out from Terminal 7 to install a new Holders Assembly, I took advantage of the opportunity to adjust it for better tension. You can do this by placing the end the Mounting Screw fits through, in the jaw flats of a pair of Needle Nose Pliers and pressing the free end back towards the pliers. A few gentle attempts and you will reach a point where the Insert snugs in and out with your fingers just nicely. I also cut a new strip of black plastic Electricians tape to the correct size and fitted it to both Insert sides to avoid any future problems. Both Headgear Type 10 now work as they should, which was a big relief!


David

[David Dunlop]

The full description of this Gasket is as follows:

GASKETS, Cork, 1 & 55/64-inch OD, 25/32-inch ID, .031 inch thick ZA/CAN 5247

It fits between the upper face of the Insert and the back of the Microphone Cover to insulate the Insert from making any contact with the aluminum Cover that might cause the Insert to stop operating.

The attached photo shows the remains of one of these gaskets that is actually made of cork. The others I have are all either automotive gasket paper, or thin manila and one was actually made from a Canadian Armed Forces Shipping Tag, you can still read some of the sections of it on one side.

It can be a bit tricky getting this gasket to stay in place while you screw down the Cover and Rubber Gasket. I found the best way was to put everything in place and then run the four Cover Mounting Screws home about half way. Then, while pulling up on the cover with my left hand, I used a wooden toothpick through the Mouthpiece hole in the cover to move the gasket around until it was centred at the hole, lower the Cover and hold it in place while tightening the four Cover Screws. Job Done!


David

[James D Teel II]

Reference post 716. You say they both work as they should. Do you get side tone? As I said previously, mine seem to work with the exception that I can’t hear myself transmit. I’m curious if “working as they should” means a full transmission test.

[David Dunlop]

Morning James.

Yes, I can pick up the sidetone of my voice in the receivers when transmitting via the A-Set and/or IC Mode on my Mk III.

I must admit I have been away from it for a few years and my ears need some serious retraining in the art of working a classic set like the 19 or 52, but I can hear myself. Wasn’t at all certain initially, but did find it.

Make certain you don’t treat the 19-Sets Microphones like modern ones. The rubber mouthpiece has to be in full contact with your face and surrounding your mouth, and then talk normally. Try blowing into the Mic, softly at first and slowly increase the air volume while holding the Pressel Button down. Your ear should pick up the sound of the air passing across the screen face of the Insert. Once your ear is ‘tuned in ‘ you should then be able to find your voice.

It can be a bit of a challenge listening passed the Dynamotor when you transmit, but it is doable. Tens of thousands of servicemen did it for many years with their lives on the line.

My 19-Set is currently on the Wireless Bench right beside a doorway with a barn door, so I stepped into the other room initially for a quieter background. When I was satisfied I was hearing what I needed to, I walked back around to the set and my ears could still monitor my voice.

A friend and I are going to try a cross town net with our 19-Sets on the 11th, so I will need some more practice. What I really like, however, is the fact that after nearly 80 years since these sets had their time in the Sunlight, I can still turn one on and work it, with all its strengths and weaknesses, and it is behaving exactly like it did for all our Service Men and Women so long ago. Gives me chills.

David

[David Dunlop]

These are the last parts of the Type 10 Headgear I wanted to document.

All of the ones I have were fitted to Type 10 Headgear and all were made by Philco and stamped as such on the rear bodies. It is interesting, however, that two distinct versions exist when one looks at the front cover plates fitted to them.

Some of these receivers have a thin, brown phenolic front cover fitted. All but one of these I have on hand show some degree of bulging out of this cover from the front of the receiver. It is almost as if some degree of moisture worked its way into the brown phenolic and caused it to expand. Because the entire rim of the phenolic is crimped in place, the expanding material had nowhere to go but bulge outwards in one or more locations. It does not seem to have any negative impact on the performance of the Receivers. It is just…noticeable.

The other Receivers, Watch, LR I have are all fitted with a thin black cover that is either Bakelite, or black anodized metal. All are dead flat smooth and all work as intended.

Where this all gets interesting in my mind is when I start grouping the oddities in the Type 10 Headgear together. What I find is:

Some of the headgear all have, brown, phenolic Receiver, Watch LR covers, a classic cloth loomed with tracer Jumper Wire fitted to the Insert Holder in the Mic and rubber coated Contact Spring backs across from the Insert rim.

The second bunch of headgear have smooth, black covers on their Receivers, Watch LR assemblies, a black vinyl covered Jumper Wire fitted to the Insert Holder and the backs of the Contact Springs are clean with the Insert Rim opposite them sporting a black strip of tape.

I cannot help but think these two sets of differences probably reflect the start and end points in production of the Type 10 Headgear. There are probably headgear out there with just one or two of these changes evident, but they would all fit a linear trend of problem solving throughout the production run of these headgear.

David

[James D Teel II]

David,

You’re correct in that I’m used to “modern” 1985-present military radios. I’ll put my “listening ears” on and try again.

James