Wireless Set No. 52 Canadian - Project

[David Dunlop]

I received a really helpful email and set of photos this morning from Chris B. in Ottawa, who owns a working 52-Set.

I had asked him before Christmas to take photos of the data plates on his Rotary Transformers so I could compare Frame Numbers on his to mine.

Some time back I had wondered about parts for these items, in particular replacement Brushes, so the next time I was inside the Supply Unit I had taken a look at the MG1A and MG2A data plates to get Model Number information from them. There was none, just the CMC Part Numbers 108-605 for the MG1A unit and 108-606 for the MG2A unit. That was puzzling, but there were a new to me set of spaces on the data plates marked FRAME NUMBER, followed by one marked SERIAL NUMBER. My thought at the time was the Frames for given Rotary Transformers might be unique to any given design and just might serve the purpose of a Model Number for parts. With only one set of Rotary Transformers to examine, difficult to prove, so I reached out to Chris for help from his set.

His photos were consistent with my set of Rotary Transformers. Both had the following information:

MG1A:

CMC Part Number 108-605 stamped in yellow below the data plate.

Frame Number stamped in the data plate: "85"

MG2A:

CMC Part Number stamped in yellow 108-606

Frame Number stamped in the data plate: "90"

Just waiting to hear back from a couple of other 52-Set owners about their Robbins & Myers Rotary Transformers, but things look to be headed in the same direction so far. Frame Numbers will be very useful, if and when a supply of NOS Robbins & Myers Rotary Transformer parts ever turns up.


David

[David Dunlop]

Well another one of these switchboards has turned up. More on that later as communications with the owner continue, however, something else has come to mind inspired by comments from Chris S. a few weeks ago.

Chris was puzzled by the change in nomenclature from what had always been, up until 1944 " Switchboard, Charging No. C5 Canadian " as per RCA Canada production of this item, to a brand new ID under Rogers Majestic of "Switchboard, Charging No. 5C Mk I Canadian". This would suggest the Rogers Majestic production was brand new and if it was, why would it have a "Mk I" designation. Basically, what happened to all the Switchboardm Charging No. 5C Canadian production? The whole naming process seems odd.

Given what I have seen in the surviving 52-Set documentation written by Canadian Marconi Company, when they had to rush to rewrite everything after the name of their set changed from the originally planned Wireless Set No. 9 development intensions, perhaps what we are seeing on the Rojers Majestic switchboards is nothing more than a typographical error that got away on them before it could be fixed.

If you look at the fronts of the No. C5 and No. 5C Mk I Switchboards, the terminals, and switch layouts and functions are virtually identical, with the exception of the additional two new pairs of terminals. Chris also noted that instead of the expected V.A.O.S. Code "ZB/CAN/BR 0183" found printed on the No. C5 Cdn models, Rogers Majestic's No. 5C Mk I was marked with the Code, "SA 3897", which is an Air Ministry Code for Electrical Ground Lighting equipment, as would have been used by the RAF and RCAF during the war.

We as yet do not know exactly when in 1944 Rogers Majestic started production of this switchboard, but we do know war production in Canada was running flat out at this time to meet shipping deadlines. The odds are that if a new switchboard requirement/request surfaced from the Air Force side of things, Rogers Majestic got the contract because RCA Canada had no production capacity left to fit it in. Rogers was probably on a very tight schedule to fulfill the contract and rather than a full new design realized the existing No. C5 Cdn switchboard would fulfill the contract requirements with a simple modification to add the four new terminals. They could clone production equipment from RCA far more quickly than designing a complete new assembly line. In that sort of tense. deadline environment, it would be very easy for proof readers to miss the simple transposition of a "C" and a "5".

Just another thought inspired by, Chris.



David

[Chris Suslowicz]

Hi David,

My thoughts on your 5C continued... (Yes, it's 2 AM and I'm doomscrolling.)

1) Canada would have received the specifications for the Switchboard No.5 as part of the WS19 manufacturing package, as it was standard for wireless trucks.

2) This would be the original (Mk.1) switchboard with the plywood back panel.

3) I suspect the UK deleted the back panel to save resources at some point - it's not necessary when screwed to the (wooden) wall of a "Wireless House" body, so can safely be dropped. For ground use the users can simply ensure it's not plonked down on anything conductive - and at 12 volts it's not going to arc over.

4) The stores code on your switchboard should be "5A" rather than "SA", and if you enlarge the image, I think the "S" is an upside-down figure "5". Since the lettering was produced by stencil or pantograph engraving machine, I think this is due to the stencil (or guide plate) for the figure being put in upside down and not noticed.

5) Canada redesigned the Wireless Set No.9 into the Wireless Set No.52, using readily available valves (tubes) instead of the single-source STC ones. I suspect they also reworked the charging switchboard to be a more generic (Charger No.1/Charger No.2) instead of (Vehicle Dynamo/Charger) and (12v Output From/Interior Lighting From) instead of Charge Batt 1 and Charge Batt 2 as on/off switching. This allowed the use of two chore horse chargers for the WS52 and was considerably more flexible.

I'm sure I've seen a plastic (Black Bakelite) switchboard with engraved and wax/paint-filled lettering, but the two I have appear to be slate, and are extremely heavy. (It's like lifting a paving slab.)

Thanks for posting the (Canadian) circuit diagram, I can use that to understand the British switchboard - that appears to have been unchanged throughout its life.

Best regards,
Chris. (G8KGS)

[Bruce MacMillan]

I was looking through the Canadiana site today and ran across docs on a truck 15cwt wireless station T1154/R106. It's described as a low power wireless station. It's interesting in that it is an army vehicle but the parts list shows several RAF part numbers. The T1154 required two different battery supplies.
Starts at file C-5817 image 5240. May be a red herring but shows collaboration between the two services.

[David Dunlop]

Here are a couple of photos of the factory NOS Switchboard, Charging No. 5C Mk I Cdn Chris Bisaillon purchased some decades ago, as part of an NOS Wireless Set No. 19 HP, built by Rogers Majestic.

Photos are on its own and next to a Switchboard, Charging No C5 Cdn for comparison. Three 5C Mk I's are now accounted for and more photos will follow.


David

[David Dunlop]

Here is where a find like Chis B. made with his NOS 19-Set HP kit so many years ago in invaluable in trying to make sense of what took place in 1944 wartime production. This equipment and related documentation is still original and untouched, never having stripped, rebuilt or repainted. A gem of a snapshot in time.

The first two photographs are of the data plates on the Amplifier and Vibratory Power Unit. First big discovery is that the RM-SA Numbers on the data plates are actually the Rogers Majestic Part Numbers for this equipment. Who knew!

The Amplifier built by Rogers Majestic is RM-SA 4241

The Vibtrator Power Supply, subcontracted to Electronic Laboratories of Canada Ltd is RM-SA 4214

The No. 5C Mk I Cdn Switchboard is RM-SA 3897

Chris B also provided a photo of the Parts List for the Amplifier. Note even more 'RM' formatted numbers.

Interesting how when we started trying to sort this information out with just one number to work with from the No. 5C Mk I Cdn Switchboard the known logical path led to closely related Air Ministry equipment.

Another interesting tidbit from these data plates. Take a close look at the VAOS Numbers on them. They look remarkably similiar to the block of numbers Canadian Marconi was using in 1944 on an interim basis: C000XX for the 52-Set. Possibly more proof of the overlaid on new equipment entering service in 1944.


David

[David Dunlop]

And then there is this little gem:

Wiring Diagram For Installing Switchboard, Charging NO 5C MK I

Big Thanks to Chris B for being the caretaker of such great equipment and documentation.



David