Wireless Set No. 52 Canadian - Project

[Bruce Parker (RIP)]

Originally Posted by David Dunlop

A quick update photo of the Carriers No. 4 after a good wash, brushing, air gun blow and vacuum. Quite a difference now from its first arrival as per the first photo in Post 218.

David

Just asking….

Is the bed on the left what your wife insists you sleep on when you get too worked up on your project? My wife demanded one too...so just asking....

[Grant Bowker]

I think it looks like a mock-up of the Diefenbunker. Not the PM's office but some of the work spaces where a duty person would nap by the work, expected to spring to life as required. I know the feeling - expected to do that at work on occasion.

[David Dunlop]

Truth be told, folks, napping has happened from time to time while working on this project.

Debbie has been very supportive. she knows how much I have dreamed of putting one of these wireless sets back together and on the air, and I have managed to hold up my end of the project by keeping the costs out of the realm of the household budget.

She has even volunteered to help me with hauling the Carriers No. 4 up onto the wireless bench in the background, into its designated resting place. Hope to get that done this weekend.

David

[David Dunlop]

Weighing in at 110 pounds, the Carriers No. 4 is the heaviest piece in the 52-Set wireless. It consists of two main parts, joined together at the sides by means of three rubber Bridge units, each side.

The lower portion of the Carriers No. 4 consists of heavy steel stock, formed and welded together to create essentially a long, U-shaped cradle mount, which is secured to a wireless table by means of two large steel clamp and bolt sets, each side.

The upper section of the Carriers No. 4 is essentially a long steel box with two inner partitions that holds the Receiver, Supply Unit and Sender components of the 52-Set. The basic box is made of one large folded, heavy gauge piece of sheet steel making up the top, rear and bottom of the wireless case. Two separate pieces, mirror images form the ends and two inner pieces form the partitions, each side of the Supply Unit. All four of these pieces, and the two end pieces of the Remote Receiver case, start out the same, but have slightly different stampings and/or holes drilled in them.

On the upper rear portion of the Carriers No. 4, a long, rectangular opening has been punched, with eight equally spaces holes top and bottom, to mount the PLUG, Assemblies, Multi and its corresponding COVERS, Metal No. C1. It is this Plug Assemblies that provides all the interconnections, but one, between the Receiver, Supply Unit and Sender.

The Cover is a single piece stamping out of the same gauge sheet steel as the case portion of the Carriers No. 4.

When removing the screws from the Cover, I was unsure of where to start. The Cover looked heavy and I wanted to be sure when down to the last screw, it stayed accessible if the Cover swung downward. Turned out to be an unnecessary concern. When the last screw was removed, the Cover stayed put. I assumed the fibre gaskets around its edge (GASKETS, Fibre, No. C1 ZA/CAN 4251) had stuck to the paint so gently started to pull backwards on the Cover. It came back about one quarter inch and still stayed put. A close look revealed a pair of retaining brackets screwed to the back of the Carriers No. 4, one at each end of the Plugs opening. Clearly, Canadian Marconi had been aware of the weight of this Cover and how difficult if could be to install it for any reason in tight quarters. Love it! A further steady pull brought the Cover completely free of the two retaining brackets, with the Plug Assemblies Multi tucked safely inside the Cover.

David

[David Dunlop]

Once I had removed the COVERS, Metal, No. C1 from its retaining brackets on the rear of the Carriers No. 4, things suddenly started to make much more sense in the Instruction Manual for the 52-Set. In particular, Section 6.11 starting on Page 137. This section explains the correct procedure for reinstalling the Receiver, Supply Unit and Sender into the Carriers No. 4, if all three have had to be removed at the same time for any reason.

The only thing that holds the PLUG, Assemblies, Multi to the 52-Set are the five individual Bakelite plugs themselves, once they are pressed into the five corresponding sockets fitted to the back of the three set components. If none of the three components are present, the PLUG, Assemblies, Multi becomes a free-floating object inside the Covers, Metal, No. C1. As a unit, this PLUG, Assemblies is heavy and the vertical wiggle room within the Covers is not enough to prevent the Plug and component sockets from lining up with each other. Same for the lateral movement to either side of the set. With the Cover screwed in place, the two Cover Retaining Brackets either side minimize the side-to-side wiggle of the Plus Assembly to acceptable limits. The exception is the depth of the Covers. See the first photo.

The internal depth of the Covers, Metal, No. C1 is twice that of the Plug Assemblies, Multi. If all three set components have been removed from the Carriers at the same time, as soon as you attempt to replace the first component, it will simply push the Plug, Assemblies, Multi to the back of its Covers, out of reach. You will have no choice at that point, other than to read up on Section 6.11 of the Manual and perform a ‘by the book’ reinstall.

I would also strongly advise you carefully clean the connecting surfaces of both the Bakelite plugs and sockets on the 52-Set. They are a snug fit to start with and it will not take much in the way of fine dirt or dust building up on the surfaces to cause them to bind against each other when being connected or disconnected. They are all black Bakelite and all of mine looked fine at first, but it is amazing how dirty a damp cloth and toothbrush gets when you start cleaning.

It is also a good idea when connecting, or disconnecting these Bakelite connectors, to apply the force you are using perpendicular to the faces of the connectors. In other words, push straight in and pull straight out. If the force you are applying gets too far off the perpendicular, the connecting faces of the plugs and sockets will bind against each other. Bakelite was never a forgiving material at the best of times and these parts are additionally, now 75+ years old. Be nice. The last picture posted here shows the damage that can happen to the Plugs if not treated carefully. Four out of the five in my Carriers No. 4 have this type of damage present.

The nice find was that the paper terminal labels inside the five plugs are minty originals.

The other photo I posted is of the back of the Plug, Assemblies, Multi. Again, a one piece sheet steel stamping, satin nickel plated. The metal gauge seems to be the same as used for the Covers and Carriers.

I have been thinking about the design of the Plug, Assemblies, Multi when it comes to all three components of the wireless set being removed from the Carriers. I have not yet seen any documentation from Canadian Marconi, or the Military end users of the 52-Set flagging this topic as an issue or problem. No revised Covers. No apparent modifications. The logic of the design may be difficult to grasp today, but it would seem to have been a valid design. The same style of connectors system was used by Marconi on wireless sets built for use by the Navy during the war and no concerns appear at that end either.

Two possible justifications for the design come to mind. When mounted on the back of the Carriers No. 4, the Plug Assemblies are open to the inner case of the Carriers. When the fans in the Supply Unit and Sender were operating, warm air would certainly be capable of circulation around the Plug Assemblies so they would stay dry. Secondly, as mentioned earlier, Bakelite is not the most forgiving substance. If the Covers were snugged up against the Plug Assemblies firmly, it is possible the shock of any blow to the surface of the Covers could transfer to the Bakelite connectors and crack them.

That’s all I’ve got on this topic at the moment.

David

[David Dunlop]

Well, it was an interesting and productive day today.

Debbie and I got the Carriers No. 4 up onto its intended resting place on the wireless bench to start with. I then took the opportunity, while the Plug Assemblies was out in the open to check the continuity of all the circuits therein. They checked out just fine. Then the individual plugs got a cleaning.

Finally, I slid the three main set components into the Carriers No. 4 and reconnected the Plug Assemblies and Cover. That is one challenging task, and I much more fully appreciate Marconi's warnings in the manual about such work, having now gone through it. It did not help that the lower bank of screws on the Cover had to be reinstalled blind because there was only seven inches of clearance between the back of the Carriers No. 4 and the basement wall. Not thrilled about eventually having to do it again when it comes time to repaint the Carriers No. 4, but at least I now know more fully what to expect.

The attached photo shows the 52-Set in its place of honour on the bench. The set from Montreal did not have the Coil, Aerial Tuning assembly with it, so I wonder when the last time was that this set actually had one fitted to the top of it?

Hard to believe I am now just two small connector cables away from having a fully integrated 52-Set. I don't think the progress on this project has fully sunk in yet!

David

[David Dunlop]

This part of the project is a ‘Planning Ahead’ segment, more than anything.

I will eventually be doing a restoration of the Supply Unit for my 52-Set, which is going to bring the two dynamotors into the picture. The main concerns with them will be the inspection and cleaning of the brushes and armatures, which is a relatively straightforward process. Where it will get interesting, however, is the cleaning and regreasing of the bearings.

This 52-Set was very likely last operated sometime in the 1970’s, and when the dynamotor bearings were last cleaned and lubricated prior to that is anyone’s guess.

Version 2 of the Parts Listings for the 52-Set, issued July 1948, identifies the grease used as GREASE, Lubricating, Andoc and it was available in 1-pound tins.

In 1954, Modification Order No. 4 was issued dealing with changing the original grease to one identified as 3-GP-683a, which was an Arctic tolerant grease, if the 52-Sets were being deployed there.

While checking the web today, it appears Andoc grease was an Exxon Product and version ‘Andoc C’ was discontinued in 2001. I have no idea what the qualities of this particular grease were, to be able to match it to a modern substitute, so I am very much open to suggestions for an appropriate substitute. I would like to track down suitable grease ahead of time, rather than have the project grind to a halt, when it reaches the point of restoring the Supply Unit.

David