Wireless Set No. 52 Canadian - Project

[David Dunlop]

Sometimes I forget what I started out with.

I dug these two photos up of this Connectors assembly when it first arrived back in May, 2019.


David

[Harry Moon]

While I'm relatively new to radios and related equipment and probably will never make the commitment as you have I do want to pass on how impressed I am every time I check in on this thread. Inspirational.

[David Dunlop]

Thank you for the encouraging words, Harry. They are very much appreciated.

I find I am at a bit of a cross roads with the Project once again, in so far as what direction to take next. I am rapidly running out of things I can do to completion, and I hate partially starting something and then having to set it aside, particularly if it is in a state of disassembly.

When I look at the Main Set Assembly now, I know the Receiver is working, as it should. All of the problems I was aware of in the Sender have been fixed, the Heater circuit functions correctly, the Blower works and all the tuning circuits work, in that the Receiver responds as it should to any tuning adjustments made on the Sender. This latter point also transfers nicely over to the Coils, Aerial Tuning Unit. The Receiver now also responds correctly to any tuning adjustments made to the Coils Assembly.

Further work on the Coils is purely cosmetic now. It needs to be fully disassembled in order to get rid of the nasty NATO paint job it received, unfortunately inside and out, and restore the wood to the original Flat Olive Green Canadian Marconi had applied to all the wooden items they built for the 52-Set. While the guts of the Coils are out of the box, the two decals on the front panel need to be returned to originals. They are currently the late post-war stick on style with white painted printing and a white border around the perimeter. The originals were the same water slide transfer decals the rest of the set had – plain black with green phosphor luminous lettering. The paint on the Coils front panel is not original, but a close match and I would like to keep it. That will depend on how successful I end up being in removing the two current decals. The big catch here is I do not have a new enough computer to be able to create the necessary artwork for the water slide decals I need to make. So finishing the restoration of the Coils can logically be put on hold for the time being. Other than the wrong ‘look’ to it, it is in excellent shape and working exactly as it should.

That brings me to the Main Set Supply Unit. The front panels absolutely need a full restoration as a result of damage, sloppy work and incorrect decals. Once again the same decal issue, so that exterior work has to wait.

On the inside, there is lots to do and some strong logical reasons for getting it all done.

The Receiver Vibrator Supply section is working almost correctly. The mystery here is the disappearance of 2.0 Volts DC from the Low Tension circuits. I have 12.73 Volts arriving into the Supply Unit but only 10.75 shows up on the meter. Correspondingly, I should be getting +150 Volts DC High Tension out of the Vibrator Supply section for the Receiver and I am only getting between +130 and +135 Volts DC. Most, or that entire drop, is likely related to the lower than normal Low Tension feed getting to the Vibrator Supply. My current thought is there are one or more bad soldering joints along the Low Tension path that are pulling the voltage down. So I need to find and fix that problem.

Second problem I am aware of with the Supply Unit also relates to the Receiver Vibrator Supply Section.

When I undo the two Cowl Fasteners and pull the Vibrator Supply out, all that comes out is the chassis. There is a sheet metal case that fits over the entire chassis that is supposed to be removable, but it stays firmly stuck inside the Supply Unit. Not good because it needs to be out of the way to access the mounting hardware for the two Dynamotors. The two Dynamotors are my biggest concern with the entire 52-Set.

I am fortunate the two in this Supply Unit are the upgraded 1945 issue ones that solved the overheating problems of the originals. From the outside they look to be in good shape, but it is the innards that are going to need some TLC before I can even consider firing them back up. The end bearings on both need to be cleaned of 1966 grease and repacked. This is the type of grease that looks like golden honey when you scoop chunks of it out of a can fresh new, so I can only imagine what it has turned into now. Adding to the fun, the original grease is no longer made so I need to find a modern equivalent.

All the brushes on both Dynamotors also need to be carefully removed, inspected and cleaned and put back in exactly the same position as they came out. And while out, the armatures of the dynamotors need to be turned by hand and carefully cleaned. If that work is not exciting enough, I have to be able to do it knowing there are no known replacement parts for any of this stuff, should anything end up needing to be replaced. Hence my reservations at the moment about diving into the guts of the Supply Unit.

Countering all that, the ‘Plus Side’ of getting the internal work on the Supply Unit completed, will allow me to finally test the actual transmitting circuits in the Sender. I can check the individual components for effectiveness until the cows come home, but still at some point have to hit them all with high voltages and see what happens.

I will keep you all posted.


David

[Harry Moon]

at some point I do want to get the 19 set up and running, Bruce McMillan moved away from being local to somewhere in Kent England. If anybody knows of a knowledgable person near my home in Burnaby BC that would be great to know. Close to my house is relative, I think we will be able to get out on the highways once they are all rebuilt.

[David Dunlop]

I hope things get back to normal quickly for you, Harry.

Having thought about it for the last day or so, I have decided to tackle the internal issues with the Supply Unit next. I think it makes the most sense to the overall progress of the project. The outside may look scruffy for a bit longer than I would like, but the performance of the set as a whole will take a quantum leap forward.

David

[David Dunlop]

And off we go, into the unknown yet again!

I have now pulled the Supply Unit from the Carriers No. 4 and it is sitting on the bench ready for a close inspection. This Supply Unit is getting interesting already.

Overall, the interior chassis assembly is remarkably pristine. Only the top surface has accumulated any significant dirt and/or surface rust and that should all clean up fairly easily. This condition looked odd, in light of the fact the Serial Number for this Supply Unit is 5792. That is early production. The other interesting bit is the Blower Cover and Receiver Vibrator Supply Cover on the front still clearly show the factory original Gloss Navy Grey paint, The discoloured varnish top coat is only on the main Supply Unit Panel that had new decals applied during the 1966 Workshop overhaul. The only reason I can think of for the replacement of the decals is that somebody assumed they were radioactive paint. That would fit nicely with the fact the Sender panel had two decals added to it stating the paint WAS radioactive. It is not. All the more reason to be happy the decals will eventually be replaced with ones patterned after the originals down the road.


The Modification Card, still in place in its holder, has proved a gold mine of useful information, which may explain a lot of the history of this, 52-Set. Modifications 1, 2 and 4 were all performed on this Supply Unit 12 June 1966, which is consistent with the 1966 Workshop Decals added to the upper left corner of the front panel. Modifications 1 and 4 are the interesting ones.

Modification 1 was for the installation of the Modification Card Holder. This Instruction was first issued 23 May 1947, when these Card Holders were first introduced and to be applied to all active wireless equipment assemblies. That strongly suggests this Supply was sitting in original packaging from whatever build date it had until it arrived at 202 Workshop, possibly as a replacement unit for the one originally in this particular 52-Set. At 202 Workshop it was unpacked for the very first time, the two Dynamotors upgraded to the improved 1945 versions, the ‘bad decals’ replaced on the front panel and the Modification Card Holder added on the top of the chassis.

Modification 2 was a simple addition of electrical tape around the right hand terminal of resister R38A at the back of the supply to prevent possible contact with the Vibrator Supply Case when it was slid into the Supply Unit Chassis.

Modification 4 gets really interesting again. This was an extensive set of modifications required to prepare the Supply Unit for operation in conditions in the high arctic. Mostly upgrades to grease and other lubricants, but a couple of valves were also swapped out for more cold tolerant ones.

So where did this 52-Set originally come from for servicing at 202 Workshop, or, where was it going to go after completion of the overhaul work, which would have been leading towards the winter of 1966-1967?


David

[Bruce MacMillan]

Harry, check out the Burnaby Amateur Radio Club. There are a few members there that also belong to the SPARC radio museum so they speak tube language. They may be able to point you in the right direction. Sadly the three people at SPARC that worked on military sets (me included) have moved away.

[Harry Moon]

Originally Posted by Bruce MacMillan

Harry, check out the Burnaby Amateur Radio Club. There are a few members there that also belong to the SPARC radio museum so they speak tube language. They may be able to point you in the right direction. Sadly the three people at SPARC that worked on military sets (me included) have moved away.

thanks Bruce

[David Dunlop]

First off, I am stunned at how pristine the interior chassis of this Supply Unit is to look at. Photos will eventually follow.

I took some time to explore the disappearing 2.0 Volts DC from the Low Tension side and discovered absolutely nothing is wrong with this part of the Supply. Whatever I feed into it, shows up perfectly on the +12 Volt Receiver Pin on the rear Connector of the Supply. So!

I have a Main Set Receiver that reports spot on accurate voltages on its meter when fed by the Remote Receiver Supply. When in the Carriers No. 4 and fed with the Supply Unit, the 2 Volts disappears. When the Supply Unit is out of the Carriers No. 4 is shows perfect LT operation. In the Carriers No. 4, 2 Volts disappears. That points to a fault, probably a poor solder joint, in the PLUG ASSEMBLIES, Multi running along the back of the Carriers No. 4. Not exactly the nicest part to have to work on, but at least I know the Supply Unit is looking really good in that circuit.

David