[David Dunlop]

I was looking over my Carriers No. 4 a little while ago, primarily to refresh my memory about what work needs to be done to restore it. The actual restoration work breaks down into initial disassembly of all the little loose bits and separating the upper Box assembly from its lower Cradle assembly, when the time comes to work on it. Locate a few missing parts. Then straighten a handful of bent parts on the right hand side, strip off all the old NATO Green paint and then repaint it in as close as possible to the factory original No. 2 Brown paint. Let it all cure and then reassemble.

As far as missing parts went, the only ones I noticed I needed were all part of the Ground Terminals system located on the lower right side of the Carriers No. 4, where a pair of heavy duty wire braid grounding straps are used to maintain electrical continuity between the upper Box assembly and the lower Cradle assembly, across the insulation/isolation point of the rubber Bridges acting as shock absorbers for the 52-Set. The problem I have is the entire front Ground Terminal assembly is missing on my Carriers No. 4 and the rear assembly is badly bent and appears to be missing its wing nut.

The photographs in the 52-Set Manual suggested there definitely was a wing nut on the rear Ground Terminal, but the front assembly looked shorter in length overall and did not have a wing nut. Not helping was an illustration on Page 53 of the Operators Manual showing a wing nut arrangement on both Ground Terminals, but only the rear terminal actually in use. I got in touch with the owners of known surviving 52-Sets to ask how their sets were configured. All came back confirming just the rear assembly serves as the Ground Terminal, using a longer machine screw fitted with a wing nut and retainer D-Ring. The front assembly is merely a second connection between the upper Box and lower Cradle assemblies, using a shorter machine screw and hex nuts. No wing nut or D-Ring.

So with the help of other owners, I now know the rear Ground Terminal is a 1-1/4 inch long, 1/4 x 20 machine screw equipped with a wing nut and drilled near the end for fitting a D-ring retainer, to avoid loss of the wing nut. The front Ground Terminal is just a 3/4-inch long, 1/4 x 20 machine screw, both ground straps are 5.25 inches long by .75 inches wide heavy duty wire braid.

However, an unexpected discovery turned up in the process.

It seems the Engineers working on the design of the 52-Set at Canadian Marconi Company were quite concerned about the ground continuity for the set when in its Carriers No. 4. So much so, that where the holes are located fore and aft on the lower right side of the Cradle assembly, to which the bottom ends of the wire braid ground straps are secured, the Engineers designed in a large section of heavy duty copper plating against which the wire braid ends would be fitted.

Don Wright in Alberta brought these plated copper areas to my attention, because they have survived on his Carriers No. 4 finished in the factory No. 2 Brown, as per the attached photo. On the Cradle frame of my Carriers No. 4, the front Ground Terminal assembly was completely gone, but all I could see was a smooth NATO Green surface. Don assured me this plating should be there because it is quite thick and should even survive sandblasting, if done, when my Carriers No. 4 underwent its repaint to NATO Green.

Out came some fine emory paper and with just a few careful rubs, there it was, nicely outlined (second photo attached). Oddly enough, once I could see it, I could then feel it with my fingertip. At the front edge of the rectangle, where the NATO Green has worn and chipped over the years, I can now just make out the glow of copper down that line. I am going to pick away at this discovery with further careful sanding and a variety of cleaners to see just how much of this hidden bit of 52-Set design I can recover. Too hard to get at the rear Ground Terminal position at the moment, but it is now marked for a closer inspection when the time comes. The approximate size of this copper plated rectangle I have found is 3.0 inches long by 1.5 inches high.



David