Wireless Set No. 52 Canadian - Project

[David Dunlop]

Today’s work on the Sender was one of those sessions that covers the full spectrum from great to depressing.

On the great side, the set screw in the grey Handles Knob on the IPA 7 – 16 MC Dial assembly only broke free about one half turn before locking up again, so I had no idea at all if it was free from the brass shaft fitting, or still biding against it. Even after a good light oil soak. So out came the puller once more. Much to my surprise, when it was set up and ready to go, it drew the Handle from the brass fitting smoothly in one continuous motion. The dial lifted off easily next and I then retrieved the small brass shims between the back of the dial and the brass fitting. Interestingly enough, there were only two of these shims on this dial assembly, as compared to the three in place on the PA TUNE Dial shaft.

When the Randle had been lifted free of the shaft, I expected to find the two small Clamping Screw Spring Retaining Pins sitting on top of the centre of the dial plate, as had been the case with the PA TUNE Handle. If you do not maintain outward tension on the spring ends protruding from the Handle when lifting it from the shaft, the pins simply drop out of their holes. When I turned the Handle over to have a closer look, I found dried grease stuffed into each pinhole to keep them in place the last time the dial assembly was overhauled. That was something I had considered once when working on the 19-Set Handles.

Even more dirt and grime was under this IPA 7 – 16 MC Dial than the PA TUNE when it was lifted free and the dial itself is going to need so heaps of TLC to bring it back to anything close to original appearance.

Now for the dark side.

You will notice in the attached photo, a rusty outline of the mounting end of the Slow Motion Drive Assembly. The spring portion has surface rust present but is otherwise in good shape. The pin on the right hand end of the drive assembly that drops into the slot on the end of the Lower Flick Drive Arm is another matter. It was corroded so badly, it was no longer round and was stuck in the slot in the arm. It took about one half hour of coaxing to work it free from the arm. I was pleased to see the arm itself was in very good shape as the pin came free. The corrosion was contained to the pin on the Slow Motion Drive. However, as the Slow Motion Drive came free and the Lower Flick Arm swing up towards the centre shaft, I heard a ‘Ping’ from the area of the Flick Lever Shaft Assembly and the Lower Flick Lever suddenly stopped swinging towards the centre shaft. Checking the Flick Lever Shaft, I found it was in a complete free wheeling mode, in control of nothing at all.

The top end of the Lower Flick Lever fits into the shaft of the Flick Lever. A second, Upper Lever comes off the Flick Lever Shaft and heads up to control the two Frequency Indicator Flags (Red and Blue) above the dial. A C-Shaped Wire Spring hooks into the bottom end of the Upper Flick Lever Arm, wraps around the Flick Lever Shaft and hooks into the top end of the Lower Flick Lever Arm. This spring provides all the necessary tension to keep the two Flick Lever Arms snugly in place against the Flick Lever Shaft and at the same time provides the necessary tension and resistance within the Flick System to make it all work. This simple little spring has either broken, or popped loose.

In the photo, you can see a portion of the Lower Flick Lever Arm just below the central brass fitting. That arm should be pointing directly at the Flick Lever Shaft, not above it as it now rests.

Welcome to the Dark Side of the day!

The only way to determine exactly what is going on with this Flick Drive now, and fix it, is to completely remove the front panel of the Sender to gain full access to the Flick Drive Assembly. There are some very logical advantages to being able to remove the front panel. It will make several repairs extremely easy. The problem is the complete lack of any documentation describing the correct way to free up the front panel and remove it. When you have absolutely no spare parts at all at your disposal for such an undertaking…

So endith my Sender work for the day.


David

[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