Wireless Set No. 52 Canadian - Project

[David Dunlop]

Thanks, Tim. I will check it out.

David

[David Dunlop]

Well I have found another receiver this past week that will be serving as a parts doner for my Main Set and Remote Receivers. It is complete but has been in a humid location somewhere just long enough to build a bit more surface rust on the chassis than is worth dealing with. Also, a number of key decals on the front have been badly damaged/chipped away. Not a choice I take lightly, but other events this week led me to conclude it was a wise decision.

I started to clean and visually check the valves on the Remote Receiver, starting with V2B, the 12Y4G Noise Limiter. I chose that one as it was missing it's shield cap and I now had a replacement from the doner receiver. You can see this valve in Post 37, horizontally mounted, mid rear chassis.

First thing I discovered was this valve is the only receiver valve that does not have any physical locking means to keep its shield assembly in place. Consequently, Marconi sweat soldered the base of the shield to the valve socket and coated the solder seam with clear red lacquer. Marconi appears to have used this lacquered solder technique throughout the 52-Set Receiver chassis. This valve is the most difficult to get at on the chassis and it takes a bit of wiggle to remove it from the shield. When it was out, I realized the top of this particular shield was different from others I have encountered. The top edge is straight cut, not rolled in, The rolled in approach makes for a very firm shield top that a cap can be pushed over very easily. Not so the straight cut edge as a close look showed several dents and bumps around it. Which explained why the cap was missing. Back to Debbie's jewellery supplies for her small, smooth faced, needle nose pliers. After nearly 45 minutes of bending, tweaking and muttering, I finally had the edge of the shield smooth enough to accept the cap. Then the second problem smiled at me.

The 12Y4G has no central key post on its base. It relies on proper seating in the socket by the pattern of spacings of the pins, No big deal for a vertical installation with no shield to deal with. Very big deal in a horizontal mount with a fixed shield obscuring any observation of the process. I ended up staring at the bottom of the socket at the back of the chassis, with a flashlight in one hand while the other twiddles the valve, which I hoped was at least starting out in somewhat correct orientation. Only took 10 minutes.

Extra valves on hand are going to be a definite asset with this project!

David

[David Dunlop]

I joined the wireless-set-no19 Group in the UK at the beginning of the year, on the suggestion of Chris Suslowicz. They have a very good reference library members can download from.

Found the 52-Set Modifications. Only 6 issued. The first one, of course, was where and how to install the Mod Card Holder on all the 52-Set components. Number four was also interesting. How to prepare the set for Arctic operations. And the fifth mod was for the removal of the pocket watch holders which were to be thrown out as the watch had become a redundant item.

David

[David Dunlop]

In January of 1945, the Canadian Army published their EME Instructions (Telecommunications F254/3 ) for the Wireless Set Canadian No. 19 Mk III. This is a very lengthy tome, which goes into beautiful, well illustrated, procedures for the complete testing, disassembly, repair and reassembly of the Cdn 19-Set Mk III. It even lists all of the test equipment required to do the work.

I would like to determine if the Canadian Army every produced an equivalent publication for the Wireless Set No. 52 Canadian. Has anyone ever seen a copy over the years?

I am planning to contact the Signals Museum in Kingston to see what they might have in their archives. It would be a great help, (if the publication actually exists) to know its Telecommunications Reference Number and when it was first published. Would not be a surprise if updates came out in the 1950's as well. They certainly did for the aforementioned 19-Set Instructions.

Thanks,

David

[David Dunlop]

Another week. Another adventure.

As I had mentioned earlier, I want to first focus on getting the Remote Receiver back up and running. There do not appear (so far) to be any electrical issues. Most work will be cosmetic and physical in nature. However, at some point I am going to have to chase electrons into it and see what they get up to. Towards that end, a huge piece of the project arrived last week…a ZE 11 Remote Supply Unit.

I had known about this item for a while, but was also aware it related to the Wireless Set No. 9 Mk. I Cdn. The ‘correct’ Remote Supply for the WS-52 is actually the ZE 12. Then I learned from Jacques Fortin, out Quebec way, that there are only a few minor component variations between the two supplies and in fact Marconi had shipped ZE 11’s with initial production of the WS-52, until production of the ZE 12 was ramped up. So I bought this ZE 11.

Externally, the supply shows the usual dirt and nicotine accumulations for its age, but overall the original wrinkle green paint and white silk screened markings are in excellent condition. The underside of the cover assembly is finished in a very fine textured silver/grey metallic paint. I am curious now if this finish was also applied to the interior of the main set carriers and the remote receiver case.

The OZ4 looks a bit scruffy and has not yet been tested. The Serial Number (3892) has been stamped on a small metal plate which was then riveted to the top of the Choke cover, over top of the white stencil that notes a location for a serial number. I am wondering if initially these supplies just had a painted on serial number and then later Marconi switched to a metal plate format to extend the life expectancy of the identification?

The outside top of the cover has the number ‘3820’ hand written in white on it in two separate locations. Possibly a cover from a doner supply.

The AC cord is original, measuring about 7.5 feet. It had electrical tape wrapped around it a couple of inches above the base. At first I though this might be hiding a splice, but a closer look indicates a rodent of indeterminate size appears to have used the cord as dental floss at some point. I will have to take a closer look at that later.

In any event, it seemed the right idea to get this supply checked out and working as the first part of getting the Remote Receiver back up and running. Same initial goal, just a slightly different start point.


David

[David Dunlop]

With a bit of free time to play with this morning, I decided to dive into the AC Cord repair on the ZE-11 Remote Supply.

I assumed there would be two main parts to this work: a physical part dealing with the placement of the cord, and, an electrical part dealing with the usual desoldering and soldering of the two cord connections wherever they happened to be.

The first step was to remove the base plate from the supply. Straight forward enough. 12 small round head, slotted screws with lock washers, three per side. 11 screws were found to have the split lock washer style, the last one an internal tooth lock washer. Easy enough to eventually upgrade the latter to the correct style. Nice surprise inside the base plate. A very minty, lacquered circuit diagram for the supply.

After admiring the diagram for a few moments, I had my first reality check. Things can get quite crowded inside this equipment! It took a moment or two to confirm where the ac cord entered under the chassis. I had hoped the anti-strain devise used on this cord would be a simple knot tied into it to limit movement of the cord back out from under the chassis. Nope! This little puppy was held firm with a small ¼ inch clamp. Roughly dead center in the photo, you can see the small hex nut securing the clamp. Just to the right of the C22A Capacitor next to the ‘22’. Once you spot the nut, the clamp curve is quite evident with the two sections of heavy ac cord looping out. One lead ran straight to a pin terminal on the AC Selector Socket. The second shorter lead went up to a terminal on the 115V/230V Selector Switch.

Fine so far.

Step 1: Lets free up the AC Cord so the 4 inch damaged section outside is now inside where it can be removed and enough new, solid cord used to reconnect everything. The crowded conditions are really starting to make an impression on me now. The hex nut and visible screw securing the clamp are tucked under the C22A Cap just enough that I know removing the nut with a ¼ inch socket should be OK, but getting the nut and supporting lock washer back in place from underneath the chassis will be the tricky bit. Best check how accessible the screw is from top side. Of course. No visible screw topside!

A few careful measurements later, I discovered the screw used to secure the AC Cord Clamp is actually one of the screw posts fitted to the Transformer Cover on top of the chassis. That pleased me in so far as having figured out the transformer, choke and their respective covers must have been added to the chassis at, or just before, the AC Cord was fitted. But that did not cheer me up too much when I realized just how much more wiggle room the assembly line worker at Marconi must have had, compared to myself, when working on this part of the assembly.

In any event, out came the appropriate sized ¼ inch socket and off came the hex nut. Some careful use of a set of needle nose pliers, and out came the nut and the lock washer, followed by the clamp.

David

[David Dunlop]

Note to self: Find the stainless steel surgical clamps you bought years ago from Princess Auto. I bought them when working on my 19-Sets because they are brilliant for fishing loose bits like nuts and washers out of cramped chassis areas.

So I now had the AC Cord free to feed back down into the chassis area. I checked the Parts Listing for the ZE-11 and the factory cord is 8 feet in length. I needed to move just over 5 inches inside to get rid of all signs of rodent flossing and end up with actually more cord to work with when resoldering the two connections.

I was able to get the cord laid out and the clamp back in position easily enough and the clamp ended up on the screw post with just enough screw exposed that the lock washer would stay put on it. But how to get the hex nut back down squarely on the screw to feed it onto the screw? No finger room at all. I knew I had done this sort of thing before in working on my 19-Sets. A cup of tea later and it all came back to me.

Two options I had used in the past depending on how much access I had for a socket to fit.

If there is not enough space for a socket to safely start the hex nut home, without risk of an angled approach cross threading the nut, I used to use a pencil, piece of dowel, or similar item. Take the flat end and attached a tiny square of double sided tape. Then press the hex nut squarely on the end. Line it up square with the screw and slowly start turning. You can tell right away if the nut is threading its way home and the nut will simply twist free of the tape when the time comes. You can then safely fit the socket to the nut to finish the tightening process.

Alternatively, if you have the space to use a socket head. Pack a bit of tissue paper or paper towel into the opening of the socket head you need to use. Follow that with a small ball of plasticine, plumbers putty or that grey window putty used to seal window seams in the Winter. Then press the hex nut onto the putty. It will stay put while you turn the socket around to install the hex nut. Any putty that sticks to the nut when you are done is easily wiped away, and you can just poke a nail into the back side of the socket to push the paper plug back out. The paper cleans the putty out of the socket and away you go.

Turns out all this was the really easy bit. As I was starting to unsolder the AC Cord from the AC Selector Switch terminal, my 40+ year old soldering iron died. As it’s final farewell, it revealed just how the connections were made to this terminal and it was not what I had hoped for at all.

This will continue once I have sorted out a brand new, variable temperature soldering station and a fresh supply of desoldering braid.

David