Wireless Set No. 52 Canadian - Project

[David Dunlop]

An interesting bit of Electronic History, Bruce. Thanks for the post.

Funny how we can sometimes grow up surrounded by a given set of standards and take them for granted as always having been there. Just checked my 3 year old Basic Amateur’s Course text and no mention of said standards transition for resistors or capacitors. Tubes/Valves are still given a mention, however.

Life is indeed a never ending learning curve!

David

[David Dunlop]

A supply of vintage NOS Carbon Composition Resisters arrived today. The 1.2M Ohm ones needed to replace the dead pair in my Remote Receiver HT Meter Circuit. Shipped up within a week from Radio Daze.

Hopefully, once the dead pair of resisters is replaced, that final meter circuit will spring back to life and I will be that much further ahead in this phase of the project.

I was also able to spend some more time detail cleaning bits of the receiver, in particular, the tuning dial Lots of nicotine came off the parts and a bit of surface rust around the dial rim. That work seems to have removed the small radius of sticking I was experiencing when rotating the dial. I did, however discover the course control knob of the slow motion drive has a wobble to it. Odd because it does not feel loose at all. It just rotates like a bent rim on a car. I will take a closer look shortly. If it is a bent control shaft assembly, I happen to have a spare in my 19-Set Bits Box, so can swap it out if the need arises.

Once the meter is back to full functionality, it will be the valves that will get a closer inspection, which means a small hiatus from the 52-Set Project while I build a British Valve Adapter for my tube tester.

David

[David Dunlop]

I recently ran across a small stash of boxed, NOS Canadian Marconi valves for the Wireless Set No. 52 and at a price of $5.00 each (Cdn) could not walk away empty handed. When received, they turned out to be 5 ARP-3's and 1 12Y4.

Over 70 years of sitting, the cardboard packaging has suffered somewhat from moisture. I discovered this by reading the outer red sleeves, which are generic in design it turns out. They state that the relevant patent information can be found inside, but I could not see/find any such paperwork at all in the ARP-3 boxes.

When I finally got to the 12Y4, I discovered the outer sleeve was indeed a sleeve. The valve slide neatly out of it, contained in an inner retainer. The outside of this retainer had the patent information printed on one side stating that the valves were "Licenced under Patents owned and/or controlled by Thermonics Limited." Patented 1925-1943 inclusive." I can find nothing at all on line now about Thermonics Limited so assume it has long since vanished from the business scene.

On the side directly opposite on the inner retainer from the Patent information was the warranty information that referred the customer to a number of Radiotron offices across Canada for exchange/service. Interestingly, they had an office in Winnipeg at 356 Main Street. That was on the West side of Main Street, midway between Graham Avenue and Portage Avenue. That entire block was levelled in the 1970's and a major office tower complex constructed. At the time the Radiotron office existed, however, it would have been right next door to the CN/CP Telecommunications Centre in Winnipeg, the local hub of Telegraph activity in Manitoba.

These inner retainers are generic in design as well, capable of holding any capped or uncapped valve of the appropriate size. a white strip on the cap end of the retainer bears a black stamped ID for the valve inside.

I am guessing that Radiotron was a valve manufacturing division of the Canadian Marconi Company. Three of the ARP-3 valves are stamped with a manufacturing date of "10'41". The other two were 1943 dates I cannot recall and did not write down. When cleaning the valves in the Remote Receiver, I noted a number were dated "9/43" and some 1944 dates showed up as well. Note to self to document that data.

No sign at all of any dating on the 12Y4's so far.

David

[David Dunlop]

A few things have puzzled me this morning about Radiotron, so I did a little digging. It became something of a 'Long Story Short…' sort of investigation.

Between the two World Wars last century, Radiotron was, indeed, a division of the Marconi Company in the United States. In the early 1920's, a massive merger of a number of electronics companies in the USA took place, key among them RCA, Westinghouse and Marconi. What came out the other side was a monster in the industry that thrived until anti-trust legislation in the 1930's forced it's breakup.

During this time, Radiotron became the prime producer of valves for RCA, Marconi and Westinghouse. Interestingly, if one finds vintage valves in original packaging made prior to the 1950's from these three companies, they will be in the same red/orange and black colours, with variations in logo for each company and all showing the same Patent time frames.

I dug out my spare valves for my 19-Sets and sure enough, a few RCA and Westinghouse valves showed up bearing the 'Radiotron' name.

Thought I would share.

David

[David Dunlop]

I took a closer look at the Slow Motion Drive on the Remote Receiver this weekend and in the process noticed that the front, fine tuning knob seemed to be set too far back on the control shaft assembly. I compared this to my backup 52-Set receiver and my Mk III 19-Set and both confirmed the shaft should be set back into the fine control knob about 1/32-inch. I also noted there is a considerable space between the fine and course knobs. Time for a closer look.

The set screw in the fine tuning knob came out quite easily but when examining the shaft assembly I found the set screw was no where even close to the keyway in the shaft it is supposed to lock into. It was actually gripping the shaft an eighth of an inch back of the keyway.

When I started on the course control knob, I discovered the set screw was located well into the knob and covered by years of dirt accumulation. Once I could reach it, it came out easily. This time as well, the set screw was not even close to its keyway. It had actually been tightened on the very leading edge of the course control shaft. Down the front face of it in fact. Only about half of the diameter of the course control knob was supported by its shaft and the set screw, when run home, acted like a lever, cocking the knob onto an angle.

After taking the time to clean the Slow Motion Drive and knobs, I reattached the two knobs, taking care to get both set screws into their proper positions. End result, the Slow Motion Drive on my Remote Receiver now looks and operates like it should.

Before and after photos are attached.

David

[David Dunlop]

Thought I would refer back to Post #65 in this thread for a moment, dealing with the tool box for the 52-Set.

I am still looking for any details regarding the missing metal bracket mounted on the rear wall of the tool box, more or less opposite to the one on the front wall on the right side. Gauge of steel, dimensions and how held in place. I think it forms the right side support for the wooden hydrometer case.

David

[David Dunlop]

Got some more time in on the Remote Receiver after lunch today. I was able to remove the dead R58A pair of HT Meter Circuit resistors and swap in a new pair. And then the big test.

Really nice to see that circuit come to life on the meter once more. It has been running for about one half hour now and has maintained a steady 157 Volts DC.

Replacing the R58A resistor set requires turning the chassis upside down to gain full access to the required panel board, To anyone doing similar work on one of these receivers, I would highly recommend you either remove the upper front panel assembly, or place the chassis upside down on a pair of 1.5 inch wood strips.

When the upper panel assembly is in place, the upper lip of the panel actually sits above the top of the receiver chassis, If in place when upside down, the full weight of the receiver (some 40 pounds) will shove the upper panel down flush with the chassis. In doing so, it exerts all that load directly onto the two thin spring steel retainers for the two pins that fasten the upper panel in place. It is a load they were not designed to handle. Just a word of caution.

David