Wireless Set No. 52 Canadian - Project

[Chris Suslowicz]

David,

To possibly brighten your day: with the WS19 they supplied replacement tuning capacitors already fitted with the "Condenser Drive Unit" such that the complete assembly could be fitted and then connected up. (I have a PA tuning assembly for the WS19 which has the two mica capacitors for the PA fitted to the rear and everything except the tuning scale fitted to the front. I also have the complete WS62 tuning capacitor and drive unit as a single repair part.)

It may be a whole lot easier to remove the tuning capacitor from the set (probably just a matter of disconnecting a couple of wires and undoing some fasteners) and fixing it on the bench) than taking the front panel off the set - even if you were planning to do that eventually.

Best regards,
Chris.

[David Dunlop]

Hi Chris.

Would that it could be so easy with this 52-Set Sender. It had to be the middle assembly of the three that now needs bits reconnected. It is completely blocked on either side by the other two assemblies. I have no idea how the left side of the Sender Chassis was assembled at the factory to even guess at a disassembly process. On the right side, the Condenser Assembly is indeed mounted by just four shock mounted screws. However, once it was installed in the chassis, T3A was installed and wired in which blocks access to the two forward screws mounting the Condenser. The rear screws are now also blocked, once a circuit board holding 4 caps and 6 resisters was installed and wired up.

On the other hand, "if" I can free the front panel easily, the full front of the Flick Mechanism that needs a fix is fully open and accessible. And hopefully, nothing will require unsoldering.

Currently, of all the screws I can see on the front panel, I have sorted what 75% of them do and I think that covers all the ones securing the front panel. The others still need closer inspection to see if they hold items to the panel that can stay put, or need to come out,,,and if the latter, how to get access to them to do so.

I am going to approach it in baby steps for sure. Trying to wrap my head around the entire concept as a single issue would empty our wine cellar!

Cheers,

David

[David Dunlop]

The FREQ MC Dial Assembly has now been taken apart, catalogued and filed. It was by far the easiest of the three to work on, but still shows just as much crud behind it all as the other two did once removed.

Next thing I have to look into is the pair of PA TUNING Dial Assemblies, and for them, I have a spare one on a parted out Coil, Aerial Tuning unit to study in detail before proceeding. May also gain some useful insights into the Indicator Dials in the process.

David

[David Dunlop]

The two PA LOADING Knob and Lock Assemblies have now been removed from the Sender panel. Set screws in the sides of the knobs require a Bristo Key but other than that, and a careful stretch of the D-Rings to remove them from the ends of the Lock Posts, it was a very painless, straight forward task.

I now have to study what this has revealed a bit to see what can, or cannot, happen down the road.


David

[David Dunlop]

It’s time to revisit these Counters for a few posts. They are an interesting item in their own right and three of them are used in the design of the Wireless Set No. 52 Kit. Two are used on the Sender and one on the Coil, Aerial Tuning No. 2A. The general purpose of all three is identical: to provide a reliable, repeatable, physical reference for tuning either the two PA TUNE Dials on the Sender, or the Coil Aerial Tuning for optimum signal performance. Where it gets interesting, however, is the fact two entirely different coupling drives were developed: one for the two PA TUNE Coils in the Sender and a second one for the Coil, Aerial Tuning. I am not sure why the two versions exist at this point, but they do.

These first four photos focus on the COUNTERS and related Coupling Drive in the Coil, Aerial Tuning No. 2A.

The first photo illustrates the Drive Assembly on the COUNTERS Side of the Coil, Aerial Tuning setup. Note the flat plate with the two studs in it. The second photo shows the corresponding Drive Assembly on the Coil side of this setup. Note the matching plate and pins as per the 1st photo. What ties these two drives together is shown in the 3rd photo, the DISCS, Phenolic, Coupling No. C1 ZA/CAN 4632. In the last photo, you can see how the DISCS sits on one Drive assembly. With the COUNTERS set to “0000”, and the Contact Wheel on the tuning coil wound all the way back to its start point at the left side of the coil, the pins of both Drive Assemblies will be 90 degrees apart and both sides will lock into the DISCS. This design is very responsive. There is no slop in the Tuning Dial and the COUNTERS start responding the instant the Tuning Knob is turned.

Next we will look at what goes on in the Sender with these COUNTERS.


David

[David Dunlop]

Continuing with the COUNTERS and their Coupling arrangements, lets take a look at how the Canadian Marconi Company dealt with this issue on the two PA TUNE Coils in the 52-Set Sender.

At the moment, the two in my Sender are still in situ and next to impossible to get at, so I will resort to using the illustrations of the relevant parts out of the Master Parts List.

The first photo is the Coupling Arm that is fitted to the COUNTERS side of the drive system. It is a tapered metal channel with a large post fitted to the wide end which serves as the mounting collar. Roughly midway down the channel an small capped pin is fitted and at the narrow end, a small slot is centered parallel to the longitudinal axis of the channel.

The second photo is of the Coupling Arms that fits on the Coil side of the PA TUNE drive assembly. This one is a rectangular, brown, phenolic plate with a small bushing post at one end and a small pin at the other. This pin has a small hole through it at the top end.

The third photo is the Coupling Spring, which when installed, provides tension to the entire Coupling Drive Assembly to remove any play in the system. In this configuration, the COUNTERS would be set to “))))” and the Tuning Wheel on the relevant coil brought all the way forward to its start point. The two Arms would be parallel and one over the other, such that the pin in the end of the Phenolic Coil Arm, passes through the slot in the steel COUNTERS Arm. When all was in place, the straight end of the Springs would be inserted in the small pin and the angle midway down the springs placed around the capped pin on the COUNTERS Arms. The curved end of the Springs is then brought across the COUNTERS Arms to wrap around the base of the large bushing. The end result is shown in the last photo.

This design also produced a drive mechanism with no slop in it at all and an instant response from the COUNTERS Dial as the PA TUNE knob is turned and the Wheel on the coil starts to move. What I don’t understand at the moment is why Marconi used two entirely different designs for basically the same purpose.


David

[David Dunlop]

The last oddity/difference in COUNTERS installation between the COIL, Aerial Tuning and the Sender has to do with the little six-sided metal plate and Locking Nut Posts fitted to each item.

The first photo shows these two items on the front panel of the Coil, Aerial Tuning. The plate measures 0.067 inches thick and the base of the Locking Nut Post 0.055 inches thick.

The second photo is of the same two items found on the front panel of the Sender. Here, the plate measures 0.125 inches thick and the base of the Locking Pin Post 0.125 as well. The second mystery. Why wouldn’t Marconi have used the same sized plates and pins for both pieces of equipment?


David