Wireless Set No. 52 Canadian - Project

[David Dunlop]

I was just going through some old notes on this part and rediscovered an oddity.

Every so often, one sees one of these HOLDERS with a thin disc of grey felt, or perhaps cork, placed at the back of it, over the three mounting screws.

Were these thin pads an actual production/supply item, or were these just ‘local level fabrications’, to reduce rattle of the pocket watch in the HOLDERS?

David

[Bruce Parker (RIP)]

Originally Posted by David Dunlop

I was just going through some old notes on this part and rediscovered an oddity.

Every so often, one sees one of these HOLDERS with a thin disc of grey felt, or perhaps cork, placed at the back of it, over the three mounting screws.

Were these thin pads an actual production/supply item, or were these just ‘local level fabrications’, to reduce rattle of the pocket watch in the HOLDERS?

David

I think there had to be a felt or cork backing. Otherwise the watch flops about in the case no doubt straining and ultimately chipping the socket at the top. My question is whether the watch was removed to wind it...which would be a very often occurrence. If so the fragile threads on the case would no doubt cause trouble very quickly (and it's not an easy item to remove and replace). On the other hand it is very difficult to pull up the knob and wind the watch while in its case. The 52 set probably would not be that bad but the watch and winder (not to mention the case itself) is not very accessible on Mk.II 19 sets.

[Bruce MacMillan]

Originally Posted by David Dunlop

I was just going through some old notes on this part and rediscovered an oddity.

Were these thin pads an actual production/supply item, or were these just ‘local level fabrications’, to reduce rattle of the pocket watch in the HOLDERS?

David

My 2P worth thinks it was local. I had bought an unopened box of 6 watch holders and upon opening there were just the holders, no extra bits. I've found no documentation on field changes with the holders or stores numbers for the backing. Looking at the many photos on google where the holder is visible none have padding. I think the solution (has been verified) was to remove the offending watch and store safely in a padded pocket.

[Chris Suslowicz]

Originally Posted by Bruce MacMillan

My 2P worth thinks it was local. I had bought an unopened box of 6 watch holders and upon opening there were just the holders, no extra bits. I've found no documentation on field changes with the holders or stores numbers for the backing. Looking at the many photos on google where the holder is visible none have padding. I think the solution (has been verified) was to remove the offending watch and store safely in a padded pocket.

I'd agree with "added by the user to stop it rattling". The GS/TP (General Service/Trade Pattern) watches that were probably used later on came in a variety of case thicknesses (also stem lengths) and would have needed some sort of packing to avoid vibration affecting the movement.

The original watch was the "Watch, W/T, Non-Magnetic" in a chrome plated iron case (to reduce any effects of the magnetic field from the power supply dynamotor(s) on its timekeeping), and was actually cheaper than the standard pocket watch. Later they used 'B' series watches (both of these types were manufactured without bows (specifically for use in holders), and I think to a specified overall size (the ones I have are reasonably consistent in terms of thickness).

The original watch holders were plated brass, but volume requirements led to the introduction of the bakelite version (which retained the same designation and stores code).

Long-stemmed watches probably won't fit the WS19 Mk.3 (fouling the power input connector), which is almost certainly why the holder was fitted to the front of the supply unit (where it is much easier to wind and set the watch without having to remove it from the holder) on the Canadian set. (I know my W/T Non Magnetic won't fit in the holder between the connectors on a British WS19 Mk.3, other watches are fine.)

(My father commented that the issued watch did not keep good time and that he used his own (a gift from an uncle - and quite how he managed to hang onto it given all the forced migration to Russia and then travel to Iraq is something of a mystery) that watch would have stayed in a pocket.)

Best regards,
Chris.

[Mike K]

The Aust. W.S. 101 has a brass watch holder which is finished in a very dark non-reflective blackish colour. These holders have a very fine threaded cap that requires some care when fitting the cap onto the base, it would be so easy to cross thread if too much force is applied.

[Chris Suslowicz]

Originally Posted by Mike Kelly

The Aust. W.S. 101 has a brass watch holder which is finished in a very dark non-reflective blackish colour. These holders have a very fine threaded cap that requires some care when fitting the cap onto the base, it would be so easy to cross thread if too much force is applied.

That's the equivalent of the W.S.1 (Battalion to Brigade (and Artillery) set) - in the days when wireless was big, heavy and very expensive. The holder is probably blackend brass - the British sets used nickel plating, I think, as a finish. ZA.4250 Holders, Watch - Brass, Nickelled, Dia. 2.1/4 in.; fitted on W.T. sets with which Watches, W.T. are issued; to take Watches, non-magnetic, W.T. (Priced at sixpence in 1940 VAOS.)

They would have been replaced by the Bakelite version to reduce the use of brass and simplify manufacture once the use of radio took off and the war went mobile. The stores code remained the same.

Chris.

[David Dunlop]

This is proving most informative!

For almost 50 years now, I have seen many World War Two Wireless Sets, which were equipped with a Pocket Watch Holder. The vast majority of these have been of the wartime Bakelite design, but I have seen one, or two pre-war issues done in the mentioned black finished brass. In all instances, this holder has been provided for use by the Wireless Operator to store their Pocket Watch while on duty. The Pocket Watch in question would have been the standard issue G.S.T.P. watch, built to common specifications by many manufacturers. This watch was an item that could be purchased by any service member, with cost charged to his payroll. Somewhere I have a document to that effect, giving the VAOS Number and actual charged cost, which was around $5.00 or $10.00 Canadian during the war.

These G.S.T.P. Pocket Watches were great at growing legs and running away, so the smart Wireless Operator would have it wound and set when coming on duty, place it in the HOLDERS while on duty and retrieve it when coming off duty.

I have been looking more closely at the 52-Set over the last 24 hours and, Surprise, Surprise, it is different.

The Master Parts Lists for the 52-Set provide the usual detailed illustration and the following Description:


WATCHES, Non-Magnetic, WT, similar in design to average pocket watch. VC 7563 C.M.C. 108-012


The Parts Listings in the back of the Operator’s Manual shows 1 Watch marked off under ‘ANCILLARIES’ and notes it being “Mounted In Case On Receiver Panel.”

Page 17 of the Manual holds the comment, “On the panel is fastened a watch holder which contains quite a good watch. Be sure that you do not remove it accidentally.”

Bruce Parker’s assessment of the locations of the HOLDERS, Watches on the 19-Sets is Spot On. The Mk II location is God Awful to work with and the Mk III a huge improvement.

On the Wireless Set No. 52, the HOLDERS, Watch is up high on the Receiver Top Panel. A standard G.S.T.P. Pocket Watch will fit in the HOLDERS, but not without considerable care getting it in and out. The problem is with the Ring fitted to the stem and the large round ball type Crown. They leave very little room to work with and the Ring must be oriented forward to make it all work. But once you do all that, anyone with chubby fingers will be really challenged to reach the Crown to wind the watch, should that need arise.

It would appear, Canadian Marconi Company anticipated that problem and solved it by ordering a special Pocket Watch with no Ring on the stem (the holes are still there) and a Crown that is flattened across the top, which barely reaches the mid-point diameter of the standard Pocket Watch Ball. This Pocket Watch goes in and out of the HOLDERS easily and can also be wound in situ if needed.

Rats! Another item back on my B-List.


David

[David Dunlop]

Another production detail for the Wireless Set No. 52 appears to have revealed itself this past week.

Back in Post #199, when my Supply Unit for the 52-Set had arrived, I posted a photo of it that showed an odd red circle on the left hand Drop Cord rubber Y-Socket. The circle had a blurry red bar across it. No markings at all survived on the right hand Drop Cord, which was in rough shape. Looking at working photos of the 52-Set since then, both wartime and postwar, I have noticed there is nearly always just one Headgear Assembly Type 10 ever connected to the 52-Set and it is always on the right hand Drop Cord. The left hand Drop Cord only ever seemed to get used to connect a short Jumper Cable to a Wireless Remote Control Unit No. 1 Cdn, typically situated to the left side of the set, somewhere. So, the left hand Drop Cord seems to get very little use over time.

Later in Post #213, I added a photo from the Operator’s Manual showing the factory look of the Supply Unit, in which you can see both Drop Cords have this circular marking, though still not readable.

While trying to keep busy with something related to the 52-Set Project this last week, I decided to take a closer look at my two Head Gear Assemblies Type 10 and related bits I had accumulated. The two assemblies are in good shape, but have the usual NATO Green Goop slathered all over the metal Mic Cases. Then I remembered I had found some NOS No. 2 Brown Mic Cases and cordage and dug them out. Glad I did!

In the attached photo, you can see the backs of both Mic Cases sport a yellow Circle with R.C.A. across the middle of them. The rubber Y-Plug on the cord has a silver circle on it with R.C.A. across it. So it looks like R.C.A. was supplying the Drop Cords and Head Gear Assemblies to Canadian Marconi Company for production of the 52-Set.

Not totally surprising considering the two companies were already partners in the shared ownership of the Radiotron Tube Company, but it is another detail I will have to try and preserve while restoring this set.


David

[David Dunlop]

Back in 2019, while still searching for a 52-Set, I was in touch with Richard Hankins in England regarding his Remote Receiver which up for sale at the time. It was very original with early style decals for the Tuning Dial that had the white centre rectangle with red and blue lettering and a nice No. 2 Brown finish on the case.

We corresponded briefly about it but I passed on purchasing it due to the alarming shipping costs, and then forgot about it.

While cleaning up some files today, I ran across the attached photo of the Remote Receiver Case. Note the hardware. It appears to be a slotted, thin head 1/4-inch hex bolt. I had no idea these were ever made!


David

[Chris Suslowicz]

I think the R107 used bolts like that to fix the set into the case. (Including a very long one that went from front to rear and had a tendency to shear off.)

(I can't get at my R107 to check at the moment, but I'm fairly sure they were thin headed bolts with screwdriver slots - presumably so the operator didn't need a spanner to change the valves, fuses, or vibrator.)

Chris.

[David Dunlop]

Chris.

That is fantastic news on so many levels! At the very least, it reaffirms my reputation as an Eccentric, Detail Mad Goof!

Very early on in this Project, I could not wrap my head around the data related to the hardware Canadian Marconi Company used to mount the 52-Set components into either the Carriers No. 4, or the Remote Receiver Case. All good, available photos from its time in service indicated hex head fasteners were in place. When the actual components started to arrive, sure enough, ¼-inch, 20 hex nuts and bolts were in place in all the expected locations, in different lengths.

The problem was, none of these hard facts lined up with the information in the Operators Manual, or in fact, the Tool Kit issued for the 52-Set. There is no 7/16-inch spanner or wrench provided to deal with hex bolts quickly and easily, and no complaints in this regard ever surfaced from the British during their trials of the set. Odd.

Second, in the Operators Manual, CMC points out in several locations that the set is reliable enough the Operator will never likely ever have to pull individual components for servicing, and all routine maintenance can be performed via the various removable panels and doors. The British Trials confirmed this. Where the Operator might run into conditions requiring removal of more than one component from the Carriers No. 4, CMC does warn the Operator it will be necessary to pull all three components and remove the Connector Assembly across the back of the Carriers to reinstall all components. This is a highly unusual circumstance, and yet, still no warning from CMC about any lack of proper tools for the Operator to do the job. Odd again.

Recently, I discovered that the upper hardware on my Remote Receiver was installed backwards according to a number of photos I had seen. Photos showed bolt heads to the outside, mine were reversed. When I flipped them around, I could not remove the upper receiver panel. The hex nuts and split washers stuck too far out on the inside of the case. One more thing that did not add up.

Now, two years after receiving Richards photo of his original Remote Receiver, I finally see the hardware used was a thin head, slotted hex bolt. That fits perfectly into the puzzle. In the 1930’s and 1940’s the slotted screwdriver was supreme in the average toolbox, spanners and wrenches were typically for working on things more robust than a wireless set.

A similar concept applies to the hardware used in wireless sets. Split washers seem very rare to none existent in British wireless equipment. They nearly always use a much thinner, internal toothed Shakeproof washer to lock things down. They take up less space.

The final interesting thing I have noticed with the larger hex hardware used on wartime wireless equipment is that the hex nuts are a lot thinner than their modern equivalents today.

My thought on all this latter stuff is that post war, spanners, wrenches and drive sets of various sizes became very popular tools everywhere, very rapidly, for two big reasons: speed of use and the massive increase in torque one can apply to the hardware. That probably spelled the end to the wartime, thinner hex nuts and bolts. It would become extremely easy to over torque this older hardware, rounding off the corners on the nuts and bolts and probably even shearing off a lot of bolt heads.

Consequently, here in Canada at least, whenever the 52-Sets went in for servicing, or maintenance of any kind, it probably became standard practise to simply remove and toss the factory original hardware and replace it with the more robust, modern stuff designed for use with modern, high torque tools.

Nice that Richards Remote Receiver survived in England all these years with little change.

Not so nice I now have to find a bolt shop somewhere that still stocks old style, thin head slotted hex bolts and old style thin hex nuts.



David

[Grant Bowker]

Not directly suitable but indicates that at least someone wants slots and hex heads on the same fastener...
https://www.mcmaster.com/screws/hex-...slotted-drive/
Were fasteners on the 52 set like those on the 19, often BA threads?

[David Dunlop]

Hello Grant.

Yes, a quick glance at the Web yesterday suggested there were a number of companies making modern slot head hex bolts. I fear the trick will be finding a company still making the vintage thin head versions.

The hardware mix on the 52-Set is consistent with that found on the 19-Set and very likely all other wireless sets of British origins, used by the Canadian Military. The BA Thread generally tends to be found, however, in just a few particular components. The Pocket Watch Holder mounting hardware is a classic, along with bits of the Tuning/Flick Drive Assemblies.

What I have noticed is the BA Threads are common enough they are listed in the Standard Hardware Lists compiled by the Ordnance Supply System. Interestingly, these slot head hex bolts do not show up on the Standard Hardware List at all for the 52-Set, so they must have been placed elsewhere in the system.

One thing I did find this morning is the ¼-inch ID split lock washers typically found on the ¼-inch mounting hardware today on the 52-Set Components, do not exist on the original Standard Hardware List. The much thinner, Shakeproof, ¼-inch ID internal toothed lock washer is the only one listed. That would be consistent with the idea the original hardware was beefed up with modern replacements post war, for convenience in servicing.


David

[David Dunlop]

It certainly is easy with large projects like this to lose track of what you have actually accomplished. There is a tendency to fixate on the things that still need to be done.

I have decided to step away from the major components for a while, for several reasons, not the least of which is to clear my head a bit and deal with something entirely different. Towards that end, I am going to tackle restoration of one of the Microphone and Receivers Headgear Assemblies, Cdn, Type 10 that I have for the set, One is complete and in very good shape, though yet untested. The second one is all there, also untested, but has issues, so I shall tackle it first.

The Illustrated Parts List for the Wireless Set No. 52 is helpful in that it shows the major pieces for the Canadian Headgear Type 10 and provides good written descriptions of them, but that is as far as it goes.

On the bright side, however, the FZ 256 Illustrated Parts List for the Wireless Set Cdn No. 19 Mk III and Ancillary Equipment, has very detailed exploded view illustrations of all the parts of the Canadian Headgear Type 10 covering virtually all of the little bits and pieces. You can see clearly where everything goes, and even better, all the hardware is shown, with relevant descriptions and part numbers.

The four photos posted today show the complete headgear assembly that requires restoration, and the three reasons why.

The first major problem is that somebody cut the leads off one receiver assembly for some reason. There is no sign the setscrews on the receiver have been touched, which is odd. These receivers were used in a variety of headgear throughout the war. In most instances, the leads would have a small brass ring terminal stapled to the end. The staples cut into the covering and insulation of the lead and connect with the central copper core of the lead. The two small screws on the back of the receiver would be removed and the ring terminals fitted over the screw and everything reattached. With the Type 10 Headgear, the end terminals on the leads are just brass staple sleeves about ¼-inch long. These are then slid into holes in the receiver below the two brass screws. The screws are simply backed off enough to allow the end terminals of the leads to slip all the way into the holes and then the screws tightened down as grub screws.

The second problem is the typical massive coat of NATO Green paint brushed on the microphone and which is badly chipped. That needs to be dealt with somehow.

The last issue I am currently aware of is the state of the heavy-duty oilcloth neckband cover. Years of exposure to Brylcreme and being rubbed between the back of a Wireless Operator’s neck and Battle Blouse have worn the cover down to its cloth core.

So let the games begin.


David

[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

[David Dunlop]

I have not yet found any detailed wiring layouts for the Type 10 Headgear in any of the Wireless Set No. 52 documentation, other than the wiring setup for the two 5-Pin Drop Cords mounted on the Main Set Supply Unit. Fortunately, that bit of data matches similar information found in the 19=Set manuals.

So first step was to draw out the 5-Pin wiring in a larger format I could more easily reference while working on the headgear assemblies. The connections for the left and right receivers were readily visible and consistent across all headsets I had available, so I added that to this layout as well.

I knew there would be additional wiring to map out in the microphones once I got them opened up so I sketched out a diagram for the Phenolic Insert Holders & Plates Assembly ahead of time from several spares on hand, and filled it in when I got to opening up the microphone cases. I have added both of those drawings here at the start to get them out of the way.

From the Type 10 Headgear I have available, I suspect production evolved through an early and a late version related to two specific parts of the Headgear: the receivers and a Jumper Wire discovered inside the Microphone Case. Details of those will emerge in due course, but I will start with information next on what turned out to be the earlier version of the headgear.


David

[David Dunlop]

Leading up to this part of the 52-Set Project, I recently checked in with the 19-Set Group in England to get their opinion on the value of cleaning the contacts on the 5-Pin Connector Plugs and Sockets. The feedback was unanimously in favour of clean brass contacts, but to only get them that way with metal polishes, such as Brasso, or my favourite, Autosol. NEVER use files or abrasives as once too much metal is stripped away, the Connector is completely useless.

So my first step at this point was to polish the contacts on both Headgear harnesses I was going to restore: a pair with excellent original looms, 5-Pin Connector Plugs still sporting their RCA Stamps, and the Headset Receivers showing good yellow Philco Stamps and C-Broad Arrow Stamps. The Microphone Cases for both Headgear were NATO Green and there was a lot of dirt on everything and hopefully I had enough spares on hand to see me through any major surprises.

Once the Connector contacts were cleaned, I connected each Headgear in turn to an open Drop Cord on my 19-Set Mk III, warmed it up and checked to see what happened with the Type 10 Headgear.

Beyond the task at hand of restoring the two Type 10 Headgear, this little test revealed a somewhat larger issue that may prove challenging down the road.

The rubber on these Headgear Connectors, and the three Drop Cords on my 19-Set Mk III, have hardened dramatically. I could not get either Headset to fully engage with the Drop Cord. The brass ring just disappeared into its mating connector and that was it. A good quarter inch or so short of fully engaged. Discretion screamed at m not to get picky at that point. The connection established worked and it was still possible to disengage the Connector. I also made a note to myself to NEVER try disconnecting the headset on the 19-Set Mk III. It was last connected back in 1982 and is probably set in place now. I will have to think the hook-up of headgear to the 52-Set very carefully when the time comes.

The first Type 10 Headgear I tested proved interesting. With the 19-Set warmed up and idling, as soon as I tried joining the headset connectors together, Pin-1 on both sides (the Pressel Relay) threw the Set into TRANSMIT Mode and fired up the Dynamotor. Not a good start. So back to the workbench to disassemble the Microphone Case and map out what was going on inside.


David

[David Dunlop]

I will start off this Post with a wee apology for the readers.

In spite of the best-laid plans and intensions, the actual physical work put into restoring the two Type 10 Headgear had no real linear flow two it once underway. I ended up having to frequently hop back and forth between the two headgear and sometimes off in completely different directions in order to sort everything out. It is taking longer than I hoped to pull all that work into a logical, understandable flow to document it all effectively. I have had to take a few more photos of things I missed originally, or take better photos and then sort them all and tie them together with hopefully sensible notes. So please bear with me.

The first two photos here show the actual Microphones Case (ZA/CAN 1557) and Covers (ZA/CAN 1564) along with the Rubber Gasket (ZA/CAN 1565) stuck to the Cover. Loose fitting Gaskets were found in most of the Microphone Assemblies I was working with, but one did show signs of being varnished in place on the Case side. Surprisingly, all of these Gaskets were still very supple. The Cover is secured by four Screws, ANC, Brass, RH, 4-40 x ½-inch and internal toothed lock washers. Once they are removed, you may be able to pull the Cover off the case, but usually I needed to gently inset the blade of a Putty Knife into the seam between the two parts and gently twist them apart. If you are careful, the gasket will simply squeeze out of the way and be just fine.

These photos also show the Buttons, Phenolic, Pressel (ZA/CAN 1556) and Springs, Steel (ZA/CAN 1569) mounted to the outer upper top of the Case by Plates Assembly (ZA/CAN 1568) on the inside. Total movement of this Button is only about1/8-inch, which closes the two Contact Spring sets nicely, assuming they are still perfectly straight and vertical.

About halfway down either inside face of the Case, you can see a set of vertical ridges cast into the aluminum. These engage slots on the outside of the Holders, Phenolic, Insert to keep it, and the Microphone Insert it holds, correctly oriented inside the Case.

The third photo shows the microphone cord Rubber Grommet and Washer factory fitted. The Washer is, in fact, the Anti-Strain for the microphone cord. The large metal crimp securing the loom at the top of the microphone cord has two small rectangular tabs 180 degrees apart, bent up from the cord 90 degrees at the top end of the crimp. The Washer and Grommet slide up against these two tabs. When the rubber grommet is slid down onto its groove on the Case, the Washer slides down the inner face of the Case and is held between the two cast columns for the Cover Mounting Screws. In doing so, it clamps the Grommet is place, making it easy to fit the Cover onto the Grommet when the Cover is reinstalled. If the Grommet has perished and fallen away as many have, the inside half will still be there protecting the cord. The only way to install a new Grommet is to split it open with a sharp razor blade or scalpel and slip the Grommet over the cord. I had to do that one of the Type 10 Headgear I restored. I thought I would explain how it all works here. Oddly, however, I can find no part number or description references at all for either this Grommet or Washer in either the 52-Set or 19-Set documents I have on hand.

The last photo in this Post shows the conditions inside the Microphone Case of what appears to be the earlier version of the Type 10 Headgear, when I first opened it up. A lot of rust dust evident and other signs of high moisture. Interestingly, the Pressel Button still functioned nicely.

Of particular note at this point, are the squares of black rubber coating the upper back portions of the two Contact Spring Assemblies. The other oddity upon opening this Microphone Case up was that the Microphone Insert was well and truly stuck in its Holder Assembly. It should have been a secure fit, but easily pulled free with ones fingers.

As you can see, the wiring is nicely tucked around the perimeter of the Holders for the Microphone Insert. In fact, the lengths of each wire to work with are very consistent with where they have to go for connection. The tracers on four of the five wires match the documentation for the 5-Pin Connector Plug. The one deviation is that a double back tracer has been substituted for the Green Tracer in the manual diagrams. At first glace, it all looks pretty normal, doesn’t it!


David

[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