Wireless Set No. 52 Canadian - Project

[David Dunlop]

It pays to keep detailed notes during a restoration project. It pays dividends to actually review them!

I have been trying to wrap my head around the reason why the Supply Unit would have such a significant voltage drop feeding the Main Set Receiver, assuming that simply because the Supply Unit is the new kid on the block, the problem must reside with it. I decided over the weekend to confirm that theory by pulling the Main Set Receiver from the Carriers No. 4 and firing it up with the ZE-11 Remote Supply Unit.

Surprise! Surprise! Same poor readings with the ZE-11 running the show. So out came the Remote Receiver and I hooked it up to the ZE-11. Perfect Meter Readings on the Remote Receiver and the signals came booming in over my 134-foot dipole. I had both the RF and AF controls at maximum and had to quickly dial the AF back about half way to get a nice listening level. Even the built in Crystal Calibrator signals were easily heard. No signals of any kind to be heard on the Main Set Receiver. Then the cobwebs slowly began to fall away and I remembered my notes.

I started working full time restoring both receivers exactly two years ago today and was working on them regularly up until near the end of July, early August 2019 when word of a possible complete 52-Set surfaced somewhere in Montreal, and the rest was history.

Digging a little more deeply into my notes I remembered I had finally got the Remote Receiver up and running very nicely, and the next step for it was going to be an actual alignment and calibration. The Main Set Receiver, on the other hand, had only reached to point of taking electrons through it completely, but not very well. The biggest issue with it was poor HT and LT voltage readings in it. My plan at that time was to start a detailed trace of the circuits starting at the incoming 8-Pin Connector and tracing what went on, using the Remote Receiver as the ‘Benchmark’.

So the odds are now saying the Supply Unit in the carriers No. 4 is probably in good working order, but needing a good cleaning up. A quick check of the +12 and +150 voltages at the Receiver Connector in back of the Carriers No. 4 next time I pull the Receiver, should confirm that point. My thought is the Main Set Receiver now needs to be brought back to good working order. Once it is able to pull in good clear signals, especially its own Crystal Calibrator, I can eventually use it with confidence when time comes to try tuning the Sender to it.

David

[David Dunlop]

I just noticed this variation this afternoon.

The first photo attached was taken from the 52-Set Manual, so it was very likely taken sometime in 1943 from an early (pre) production Carriers No. 4. Notice the bottom of the mounting rails at the side of the Carriers for the Coils, Aerial Tuning to be fitted The end is cut back at an angle upwards where it sits just in front of the hole for the Mounting Clamp to be installed. Improved access perhaps?

The second photo is the same rails on my Carriers No. 4. It has straight cut 90-degree ends.

Does this mean there might be early and late production versions of these mounting rails for the Coils, Aerial Tuning?

Another possibility is the angled cut never made it into production. Same reason applying in either case: Production Line efficiency and streamlining removed a step deemed unnecessary.

David

[David Dunlop]

It has been a while since I last worked this little sub-project, but I need to get back to it now since I will be needing a completed replica of this particular Connector soon enough. It helps the Receiver and Sender communicate with one another and it will have to be ready to go when I get the Main Set Receiver fully up and running.

By means of a recap, I last worked this sub-topic back on Page 16, Post #476 of this thread.

Note to Self: It would be a good idea to keep a ‘topic log’ handy so even I can readily find information I might need to refer back to at a later date.

When I left off this work, the central pin assemblies just filled the brass sleeves, so there was no room at all to insert any HT Cable. First new step was to trim the black insulation back to just ¼-inch in length and trim it square. This will now allow one half inch of cable to fit into the sleeve

The next step will be to trim one end of the HT Cable I nave to expose enough of the central, braided copper core wire to pass completely out the end of the central pin when the cable is fully seated in the sleeve. This should work out to be about 1-1/2 inches. I will also need to pick up a small assortment of yellow heat shrink tubing and replenish my stocks of black heat shrink. The plan is for this first end of the Connector to be the insulated end located at the Receiver, and this end also bears the yellow ID Sleeve for the Connector.

David

[David Dunlop]

I was able to move forward on both the Reno and this sub-project today.

The sub-project was broken down into three steps, the first step was the one completed today, and for a variety of reasons it was the most important as it put a number of assembly theories for this LEADS to the test. All have passed so far.

The first thing was to measure off 1-1/2 inches back from one end of my piece of 7mm rubber sheathed, braided copper core HT Cable, and tape that point off. This is the start of the process to get that measured length of the central copper core exposed to pass through the tip assembly of the LEADS.

Once measured off, I used a thin. Blade cutter to slice through the outer rubber sheath of the cable at the edge of the tape. I then made a longitudinal cut from the circumference cut at the tape to the end of the cable and peeled off the rubber sheath to expose the inner insulation.

I was lucky the inner insulation was a soft clear plastic product that when cut into carefully, the insulation could be carefully bent at the cut and it would slowly split by itself to the inner copper core. I removed the insulation in two sections as shown to make it easier to slide the insulation off the copper core. As I removed the second section of insulation, I slowly twisted the insulation in the direction of the stranding on the copper core to tighten up the core wires as much as possible. I wanted to do this so it would all easily clear the pin assembly as it passed through it.

The next step was to insert this end of the cable all the way into the pin terminal I had fabricated.

David

[David Dunlop]

Once the cable was in the pin terminal assembly, I pulled it all snug with my fingers and then bend the copper core 90 degrees over the tip of the pin to secure the cable at the inner end of the pin terminal assembly. The pin is a nicely rolled tube and I made certain the core was bend 180 degrees away from this rolled seam. I wanted to take advantage of that seam for solder to wick down the full length of the pin to ensure a solid bond between the copper core wire and the inner wall of the pin. You can see that slot facing the camera in the first photo.

I then placed a small ring of solder round the base of the pin at the front end of the sleeve with the cable held vertically in a small bench vice. My plan was to use a propane torch for the soldering rather than an iron, to avoid any lateral load on the pin from holding an iron to it to heat the pin. I did not want the pin ending up on an angle. I also had to ensure the base of the pin was firmly soldered to the metal sleeve assembly for maximum pin stability. This would also make the pin terminal ‘hot’ electrically, just like the originals were.

When I heated the tip of the pin with the propane torch, I could watch the small solder ring at the base, as soon as it melted, I could remove the flame from the pin and add solder to the tip of the pin to secure the copper wire core inside it. I could also then go back and add more solder to the base joint, if necessary. It worked out pretty slick.

Once the pin had cooled, I snipped off the excess copper wire core from the tip of the pin and filed down any excess solder from the pin and base of the terminal assembly.

The final part of this work was sorting out the insulating sheath to be applied over the Pin Terminal Assembly, as per the original. Once the insulating sheath is applied to this end, by default, it becomes the Receiver end of this LEADS Assembly, as it will no longer fit through the eye screws along the top front of the three 52-Set Components in the Carriers No. 4. The manual makes note that the Operator must always insert this cable, exposed Pin Terminal first, from the Receiver side of the setup. The illustrations and photos in the 52-Set manuals are not that detailed for this information, but I had a similar Aerial Lead for my 19-Set I used for reference. I also had a section of the right, thick walled heat shrink tubing that just slipped over the Pin Terminal Sleeve. Once cut to a suitable length, slipped into place and given a shot from a heat gun, I was done.

This Sub Project will continue.

David

[David Dunlop]

As mentioned in Post #543, there are three main parts to this Sub-Project. The first part, now completed, was to fabricate the Receiver end of the LEADS, as it was the most complex.

The second part will be to add an Identification Sleeve to the LEADS.

From what I have seen from available photographs, this sleeve is between one and two inches in length (closer to the two end) and in most instances is yellow in colour with black lettering. A few photos suggest there might also be a version out there with a brown resin impregnated sleeve. The yellow one, I think, is early production as the illustrations in the manuals show it with “ No. C7” just legible. The 1948 Update to the Master Parts List shows this illustration but notes the wording on it is early production and should be ignored.

The challenge I have encountered with this ID Sleeve is getting the right size of sleeve in yellow. A 9/32-inch Inside Diameter just slides nicely over the 7mm HT cable for the LEADS. I have been able to source thin wall heat shrink tubing locally in that size, but only in black. I like the idea of the thin wall heat shrink since the actual location of this sleeve in photographs varies from right up against the Receiver Pin Terminal on the LEADS to nearly at the right side partition wall on the Carriers No. 4, between the Receiver and Supply Unit. It is possible it was a lose sleeve in the first place based on the photos, so I would not have to heat it in place. This offers a second bonus. Thin wall heat shrink tubing tends to be much more flexible in its unheated state than post heating, so it would have added flexibility for the large curve the LEADS makes from the Receiver AE Terminal around to the first hole it encounters in the Receiver/ Supply Unit partition on the Carriers No. 4.

So the game plan for the sleeve is to find an appropriate shade of yellow spray paint, cut an appropriate length of black 9/32-inch ID heat shrink tubing and paint it. Once cured, it will slide easily enough onto the open end of the 7mm cable I am working with and I can move it up to the Finished Receiver Pin Terminal end. I can then take my time looking for appropriate black lettering to add to the ID Sleeve,

Once the ID Sleeve is finished and on the cable, I can measure out the correct length of cable to finish this Sub-Project and add the Sender Pin Terminal Assembly to it. The 9/32-inch ID of the heat shrink is too narrow to fit over the 8mm OD Pin Terminal Sleeve, so the heat shrink tube has to be slide in place before the cable can be fully completed at both ends.

I will keep you posted.

David

[Chris Suslowicz]

Originally Posted by David Dunlop

As mentioned in Post #543, there are three main parts to this Sub-Project. The first part, now completed, was to fabricate the Receiver end of the LEADS, as it was the most complex.

The second part will be to add an Identification Sleeve to the LEADS.

From what I have seen from available photographs, this sleeve is between one and two inches in length (closer to the two end) and in most instances is yellow in colour with black lettering. A few photos suggest there might also be a version out there with a brown resin impregnated sleeve. The yellow one, I think, is early production as the illustrations in the manuals show it with “ No. C7” just legible. The 1948 Update to the Master Parts List shows this illustration but notes the wording on it is early production and should be ignored.

The challenge I have encountered with this ID Sleeve is getting the right size of sleeve in yellow. A 9/32-inch Inside Diameter just slides nicely over the 7mm HT cable for the LEADS. I have been able to source thin wall heat shrink tubing locally in that size, but only in black.

David

Um, not wishing to rain on your parade but heat-shrink tubing is a fairly recent invention and definitely post-WW2. (From the patents it looks like a mid-1950s development at the earliest.)

The WS19 (etc.) connectors I've seen have used printed & varnished cambric sleeving, metal tab-fastened ID labels, and printed rubber tubing (usually yellow or pink), plus pasted-on paper labels for fairly early stuff not expected to be exposed to the elements. Printed (shrink-on?) plastic sleeving is mainly seen on later Larkspur and Clansman cabling.

The expandable rubber sleeving is Hellerman/Tyton and there are various hand tools for applying it (as labels or number sleeves) to cables. I bought some of the yellow variety but am not sure it's small enough for the P11 cable used for aerial leads.

I'll see if I can get a photograph of the leads included with the "Dummy Aerial No.2 & No.3" set I have, which I think will use the same construction as the WS52 aerial lead. (The pin connectors on the ends are nickel-plated turned brass and uninsulated apart from a black rubber sleeve covering the cable joint to the connector.)

Best regards (and probably apologies for not posting this earlier),
Chris.

(The 'salmon pink' rubber sleeving tended to be used on internal equipment wiring and connecting cables for test equipment - the latter probably as a distinguishing mark to prevent it leaving the workshop with the repaired kit.)