Wireless Set No. 52 Canadian - Project

[David Dunlop]

Woot! Woot! Success with this morning's quarter turn!

The grey Dial Knob popped free and I was able to complete the disassembly of the PA TUNE Assembly down to the front panel.

You can see the amount of dirt and whatever else that dripped down the panel behind the dial over the years and in the second photo, the amount of dark crud that accumulated between the grey knob and it's brass shaft fitting.

Next up will be the middle, I.P.A. 7 - 16 MC Dial Assembly. It will be interesting to see how that one goes.

David

[David Dunlop]

The Crud Saga continues.

Started work on disassembling the I.P.A. 7 - 16 MC Dial assembly last evening. The POINTERS and hardware were easily removed. The little grey FLICK Lever Knob, however, has a mind of its own. The top mounting screw and set screw both came out easily, but once again, the knob is stuck to its shaft.

Once more into the light oils we go.

David

[David Dunlop]

While waiting for the magic to happen once again with the stuck Flick Lever Knob on the I.P.A. (Why do I always want to have a beer when I type this?) 7 - 16 MC Dial Assembly, I decided to clean and polish out the varnish on the brass shaft fitting on the PA TUNE condenser shaft that gave me so much grief.

I started late last evening and finished this morning. It probably has not looked this bright and shiny since the day it was cast and machined somewhere in a long forgotten shop back in 1943/44.

The grey tuning knob now just moves up and down the fitting snugly, but has yet to have the visible oxides on its inner surfaces buffed out. It is interesting that the 52-Set documentation notes the Flick mechanism parts for the 19-Set are identical to those of the 52-Set and the 19-Set parts can be used in the 52-Set, but the practise should be avoided if at all possible because the 52-Set items were made to much finer tolerances, Seems right enough. I have noticed the tuning knobs on the 52-Set Receivers, and now this Sender fit much more snugly on their fittings than the 19-Set equivalents.

David

[David Dunlop]

I was looking at the current state of the Sender front panel this morning and noticed something odd about the layout of the PA TUNE Dial setup.

All other similar dials on the 52-Set, and indeed all similar 19-Set dials I have ever seen, make use of a pair of these PLATES, Stop, No. 1 with one being positioned either side of the dial. In this case, only the left hand side PLATES is installed.

If one looks closely, however, the set screw used to lock the PLATES in position is still present on the right hand side of where the dial would be, but the hole about ¾-inch below this set screw, where the slide rivet would be located, is missing completely.

That raises an interesting question as to why only the left side PLATES, Stop was ever fitted to the PA TUNE Dial on the 52-Set Sender. Seems an interesting exception.


David

[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

[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

[David Dunlop]

One last little bit on these COUNTERS on my 52-Set Sender. As per the first photo attached, the PA TUNE COUNTERS on the left side had been overextended at some point and no longer reads “0000” when it should.

After a careful study of the COUNTERS on the front panel of my parted out COIL, Aerial Tuning, I was able to confirm the removal of the three large screws (one upper in the decal and the two lower ones in the tack welded plate added around the dial shaft assembly) will free the complete COUNTERS assembly from the front panel, as shown in the second photo. This will hold true with the front panel of the Sender as well.

At that point, I should be able to loosen the four small screws around the actual indicator dial just enough to allow the gears to be freed from one another. See the last photo. I should then be able to re-zero the COUNTERS and retighten the four screws carefully to bring the two gears back together and problem solved on that front.


David

[David Dunlop]

One other oddity I forgot to mention with these Counters.

If you take a close look at the two sets of photos in Posts 280 and 281, you will notice the gears and drive bushings are all fitted to their respective shafts by taper pins on the Counters used with the Coil, Aerial Tuning No. 2A

On the Counters used in the Sender, these gears and bushings are all mounted by means of Bristo Set Screws, which have been doubled up on each gear, each pair set 90 degrees apart.

David

[David Dunlop]

The next stage of the Sender front panel disassembly has been working on the removal of the Blower assembly from the access door. The first step in this is to remove the COVERS, Metal, Blowers, Electric from the front of the door. This is necessary to gain access to the three machine screw heads of the hardware holding the mount for the blower motor in place.

I found the ¼-Drive Socket Set worked best for this when a universal joint was added between the socket and handle as the upper two nuts holding the COVERS in place are quite close to two of the motor mounts on the inside of the door. Clear lacquer has been used to secure the nuts, but they break free quite easily.

Interesting to find the screen on the front of the cover had a small trim strip of metal folded over its edge. It keeps all the sharp ends of the screen wires out of the way, likely prevents the screen from unravelling and provides a good mounting surface for the 12 spot welds used to secure the screen behind the front lip of the COVERS.

The four posts used to mount the COVERS to the access door are described as:

SCREWS, Spade, 6-32 x 11/16-inch No. C1 with a 0.144-inch dia. hole in the flat end. ZA/CAN 4372

This hole takes a small rivet used to mount the screw to the inside of the rim of the COVERS. The four screws are fitted in a square pattern around the COVERS rim.

Once the COVERS has been removed, one can clearly see the three slotted, round head machine screws holding the Blower Mount in place. The crud on the fan blades is largely just dust with some zinc or cadmium oxide build-up, but it all rubs off rather easily.


David

[David Dunlop]

Removal of this assembly from the Access Door is going to be nice and simple by looks of it.

Only one wire needs to be disconnected, which is the main feed line from the 8-Pin Plug on the back of the Sender running up to feed into the RF Choke L30B (tied in place on top of the board), and the Capacitor C3AF, mounted directly underneath the choke on the bottom of the board.

The entire motor assembly at that point can simply be removed as a unit by removing the three Machine Screws.

David

[David Dunlop]

I was sitting staring at the Sender this morning with a fresh mug of tea, when I noticed a detail about these PLATES I had missed in my earlier Post #274 regarding them. Not that what I noticed provided any answers to the mystery already identified. It just adds to it.

As you will notice in the first photo attached, all five of the PLATES, Stop, No. 1 fitted to the Sender panel are dimensionally identical to each other. Some look a bit wider but that is just dirt accumulation on, and around them. What I did not notice earlier, however, was that the spacing, centre-to-centre for the rivet and set screw on the lone PLATES for the PA TUNE Dial, is a lot shorter than the other four plates to its left.

The PA TUNE PLATES has a centre-to-centre mounting space for its rivet and set screw of 9/16 inch. The other four are all 1 inch centre to centre for the same measurement.

I checked the measurement on the two PLATES on the 52-Set Receiver and, as shown in Photo 2, they are both showing the wider (1 inch) centre-to-centre distance.

Now my curiosity is really peaked! Not only do I not understand why only one PLATES was used for the PA TUNE Dial, with installation for a second PLATES partially abandoned, but now I would love to understand why a different hardware mounting pattern was used for the one lone PA TUNE PLATES.

This is probably boring as hell detail for most of you, but with so little documentation about the design and production of the 52-Set having survived from the Canadian Marconi Company, I thought noting these detail bits here at least preserves the information, and if none of us can figure it all out now, perhaps somebody down the road will.

David

[David Dunlop]

I was able to do a quick unsoldering of the power cable to the BLOWERS Assembly this morning and remove the BLOWERS.

The first photo shows the BLOWERS Assembly still mounted to the Access Door, but free of its power connection to the Sender.

I can see no useful need to remove the BLOWERS from its Mount so shall leave them as an easily serviced unit. In the second photo you can see the free standing (sitting?) BLOWERS with its hardware. The positioning of the hardware is relevant to the three legs of the mount. Notice that there is no lock washer for the hardware used in the upper right mount (viewed from the front of the BLOWERS). That is the mount where the ground connection is made for the BLOWERS with a locking terminal that fits under the hex nut. All hex nuts were clear lacquered in place when installed.

The last photo is an important one. When I was examining the BLOWERS in situ on the Access Door, it looked like the three short posts on the BLOWERS Shock Mount were riveted in place through the rubber bushings, but I was not absolutely certain of that. When I had backed off the three hex nuts securing the mount, the three posts moved with the BLOWERS assembly, but when the BLOWERS was finally free from the Access Door, I gave one of the posts a gentle turn and it pulled free of a metal sleeve fitted inside the rubber bushing. So be careful of these three posts should you ever be removing the BLOWERS from your 52-Set. They could go dancing off somewhere inconvenient if allowed.


David

[David Dunlop]

I was a little concerned about these two KNOBS on the 52-Set Sender.

On the Receiver, these two KNOBS are mounted to the lower front panel assembly by means of lock washers and hex nuts and when the upper front panel is removed, the hardware is easily accessible for removing the KNOBS. Things did not look so promising for the KNOBS on the Sender.

First and foremost, any hex nuts behind the front panel would be totally inaccessible on the Sender. I did reason, however that if the front panel assembly was the last big item to be fitted to the Sender Chassis on the Production Line, when I removed the front panel, I should then be able to the elusive hex nuts to restore the two KNOBS and then remount them. For whatever reason, it looked like when this particular 52-Set was in for major service in 202 Workshop in 1966, somebody did not bother removing the KNOBS and merely over sprayed them, chipped paint, dirt and all, with a new coat of varnish.

Out of shear boredom for the most part, but rationalizing the trip to buy another bag of bird feed, I dropped into the local Peavey Mart on Saturday, and while there discovered a small, 1-1/8 inch diameter flexible inspection mirror. Turned out to be the perfect size to slide into the right side of the chassis to look between the two Flick Mechanisms at the right hand KNOBS hardware with a small flashlight.

Happy Dance! Instead of using hex nuts and lock washers to mount the two KNOBS on the Sender (as per the Receiver), CMC must have realized how difficult they would be to access for any required replacement. Their work around was to spot weld a small rectangle of heavy gauge steel behind the front panel where the KNOBS were to mount, and tap this small bit of metal with a hole to accept the threads on the KNOBS.

A gentle counter clockwise turn of the two KNOBS loosened them and off they unwound. In the photo, you can see the drip ring of varnish that accumulated on the front panel around the base of each KNOB.

One more pair of items off the Disassemble List!

David

[David Dunlop]

A couple of more quick photos.

The first shows the front panel of the Sender with the crud that had accumulated inside the COVERS Assembly, having been cleaned away from the Access Door. Like the two Knobs, the last 202 Workshop overhaul saw the COVERS remain in place and get recovered in a new coat of varnish over existing dirt and paint chips. I had suspected this following a closer examination of the COVERS earlier, when removed from the panel, and a thin varnish ring under the crud on the door confirmed it.

The second photo is of the inside of the Access Door. The CMC Part Number of the door can be seen under a coat of varnish at the lower left bottom edge of the door. I do not yet understand the significance of the large blue "V" Stamp in the lower right corner. I do recall seeing another large single blue letter stamped somewhere else on one of the 52-Set pieces but have not yet tracked it down. In the upper right corner, on the reinforced lip of the door is a round blue CMC Inspection Stamp with the number '700' at the bottom of it. Just above the "V" is a second CMC Inspection Stamp that has been double struck. I can make out a "73?" at this point.

David

[David Dunlop]

By far the easiest items to remove so far in this project.

With the BLOWERS off the Door Assembly, I was able to get a fingertip up under the top lip of the panel and jamb the hex nuts up against the back of the front panel. It felt like both hex nuts were only on the Screw-Eye shanks about one nut thickness up. A careful counter clockwise turn of the Screw-Eye and each unfastened smoothly.

These two bits had to come out because they pass through both the front panel and the front upper angle of the chassis frame assembly. Now both tagged and bagged.

David

[David Dunlop]

I was initially thinking I would be able to simply unscrew the antenna feed line from the centre rear terminal of this SOCKETS Assembly and it would lift off with the front panel assembly. Closer inspection eventually proved ’no such luck’.

Of the three machine screws securing the Sockets Assembly to the front panel of the Sender, only the lower left one is mounted directly to the front panel. My recent inspection mirror purchase proved useful once again, as when I took a closer look at the other two sets of hardware behind the front panel, I realized both those corners of the chassis frame had also been reinforced with steel gussets similar to the ones evident in the second photo. Fortunately, there is enough clearance behind the front panel to reach all three hex nuts with my ¼ drive socket set.

The challenge is going to be releasing, and removing the 3/8-inch hex nut on the centre terminal on the back of the SOCKETS Assembly. There is no play whatsoever in the heavy duty solid wire feed to the terminal connector held in place by that hex nut and the terminal connector itself is angled downward, reducing the swing one can get with a small wrench. It’s shaping up to be one of those fifth of a turn, flip the wrench, fifth of a turn kind of tasks.

David

[David Dunlop]

It was a bit of a slow process last night to get the SOCKETS, Antenna assembly off the front panel, but I am sure glad the Sender is resting safely on its back for this work. Gravity definitely works in ones favour when removing hardware. Especially when so much of it turns out to be plated brass and you have no hope of securing, or retrieving it, with a magnet. I have only had one part get away on me and it simply fell down to the back of the chassis onto the work desk.

As expected with this SOCKETS, I had to start on the centre rear terminal post with a small 3’8 inch spanner from the right hand side and work the retaining hex nut loose a couple of turns. The locking ring terminal on the end of the antenna feed wire fits between two small flat washers and then the hex nut was applied to tighten everything down.

Once the hex nut was loose, I switched to my ¼ drive 3/8-inch socket with no handle. There is simply no room to use one. I was able to place it over the hex nut and hold it there with one fingertip of my left hand, coming in from the top of the chassis. I could then reach in from the right side of the chassis with thumb and index finger of my right hand to slowly turn the socket. When the hex nut came free of the centre post, it simply dropped inside the socket and the flat washer rested on the outer lip. I could then place the socket down on the phenolic board behind the SOCKETS, Antenna and slide it to the right side of the chassis for removal. A pair of small needle nose pliers was then used to gently move the antenna feed wire and terminal off the post and the inner flat washer just dropped onto the phenolic board where I could retrieve it with a fingertip.

The three sets of hardware that actually mount the SOCKETS, Antenna to the front panel of the Sender are held in place with 5/16-inch hex nuts. There is enough space behind the front panel to access them with the appropriate socket on a quarter drive handle, but not much room to swing the handle. The solution was to hold the socket in place and use a screwdriver to undo the machine screws from the front of the SOCKETS. As soon as the screws loosened, I found I could easily unscrew them and pull them out. The hex nuts and small lock washers simply fell back into the 5/16-inch socket. Interestingly enough, only the mounting hardware in the lower left section of the SOCKETS still had their original lock washers (external star style). The other two must have disappeared when the Sender was overhauled.

Down to just a handful of things to release from the front panel now and then it should be just a pile of screws to undo to release the front panel from the chassis assembly.

David

[David Dunlop]

Here is how the Sender front panel looks now.

David

[David Dunlop]

A few more things are now out of the way today.

First off, I removed the mounting screws for the two PA TUNING COUNTERS. It was again interesting to notice, with this type of work, the number of screws one finds that have clearly been serviced at some point and they are missing their lock washers.

In any event, when the last screw came out of both COUNTERS, they both rotated very so slightly in a counter clockwise direction. You can just see the lower left side screw holes are now slightly blocked by the mounting plate of the front of each COUNTERS. Nothing a round wooden toothpick cannot realign when the front panel is ready to go back on.

David

[David Dunlop]

The second bit of work was removing the three 1/2-inch hex nuts and internal lock washers from the three switch assemblies along the lower right portion of the panel. I found a box head spanner gave the best support on the hex nuts for this work.


David

[David Dunlop]

This last bit of activity was more of an in depth study than actual physical work. I shall attempt that work tomorrow morning when my head is clear.

I was suspicious some time ago that the Power Selector Switch for MED, LOW and HIGH Power that is mounted directly above the LOCKS, Panel, looked very much like the Selector Switch on the front of the Canadian Wireless Set No. 19 Mk III Supply Unit No. 2. I took a look through the Parts Manuals for both sets this evening and indeed it is: SWITCHES, Toggle, 4-pole, 3-position ZA/CAN 0178.

What struck me as odd when I got my first live look at the 52-Set Sender, was the fact the SWITCHES, Toggle was set so far back from the rear side of the front panel. Only about half of the toggle lever actually sticks out from the panel. Eventually all cylinders started firing and I realized two key things. First, space was needed behind the panel for the lock slide to move up and block the toggle lever from reaching its lowermost, HIGH, power position. Second, the front mounting plate on the SWITCHES, Toggle was designed for a flush fit behind a wireless panel. Point One does not allow this, nor does the fact the LOCKS, Panel occupies the position where the lower mounting screw for the SWITCHES, Toggle would go on the Sender front panel. The work around for this by the Canadian Marconi Company Engineers is rather interesting.

A set of three cylindrical spacers was employed, along with a small, rectangular adapter plate, thereby keeping the switch and the lock unmodified.

In the last photo you can see two long spacers closest to the camera at the bottom of the Sender. These allow the two mounting screws for the lock to pass down and through the adapter plate. Between these two spacers you can see the thin line of the bottom edge of the mounting plate for the switch, with the square lock nut spot welded to it. Normally, the lower mounting screw for the switch would come in from the front of the plate and into the square nut. In this case, the mounting screw comes in through the adapter plate at the back and then into the square nut.

In the background and to the right of the lower right spacer, you can see the smaller spacer that is used for the upper mounting hole of the switch assembly. The upper spacer is shorter than the lower two to keep a constant gap between the rear of the Sender front panel and the switch mounting plate. It will be an interesting exercise getting that shorter upper spacer back in place when it comes time for reassembly.


David

[David Dunlop]

Removal of the LOCKS, Panel and SWITCHES, Toggle combination this morning went rather smoothly.

I started with the bottom pair of LOCKS mounting screws by placing a 5/16 –inch socket on the underside hex nut and a screwdriver in the machine screw head to hold the screw. Then turned the socket until the hex nut was loose, Switched from the socket to pinkies to hold the nut and removed the machine screw by hand as well. When both machine screws had been removed, the LOCKS assembly was still snug against the back of the Sender front panel.

Next step was to use a screwdriver to gently loosen the top SWITCHES mounting screw about three turns. This relaxed the entire assembly enough I could use a pair of tweezers to remove the lower two mounting spacers. I then carefully removed the top machine screw by hand.

At this point, the lower end of the LOCKS and SWITCHES drops noticeably but not enough to extract the LOCKS. About one inch of swing is needed to allow the lock cylinder to drop far enough it can pivot free from the panel. It is prevented from doing that because of the mass of switch wiring the assembly now rests on at the top end of the switch back.

To get the clearance needed for the lock cylinder to swing free, the switch toggle needs to be able to drop free from its panel hole and move towards the panel hole for the cylinder. I put my two index fingers either side of the switch plate close to the toggle and applied enough downward pressure that I could see a gap open between the back of the Sender panel and the top of the rear spacer. I then reached in with the tweezers and pulled out the rear spacer. A little more angled downward pressure was applied to the switch plate and the toggle dropped free of its hole and moved down the back of the panel enough the LOCKS dropped free and could be removed. The tip of the switch toggle came to rest just at the top lip of the cylinder hole.

I gave the LOCKS a quick wipe to clean off the 3 in 1 oil I had applied to keep the cylinder and slide free. I thought I might find the model number or key code stamped on the body of the lock somewhere but it appears the only visible marking so far is a small horizontal oval stamped roughly centred between the two mounting holes on the back of the lock body with “CORBIN” inside the oval. I will take a closer look at that later. Also on the backside on the lock mounting holes, you can just see the small recess at each hole where the top ends of the spacers drop.


David

[David Dunlop]

With the LOCKS, Panel and SWITCHES, Toggle assemblies both safely out of the way now, I can count 25 (including one broken one and one missing one) likely candidates for being panel screws holding the Sender front panel to the main chassis frame and/or sub chassis panels.

I have a piece of HD foam insulation available which is a little smaller in size than the front panel plate and I will be using that to fasten the panel screw into as I remove them. I have never been one to dump all the screws from something in a big pile and randomly stuff them back in wherever when I have finished working on something. It may take a little longer to organize this approach, but nobody is paying me by the hour to do the work and I know if a screw is going back into a hole it came out of easily, it should go back in just as easily.


David

[David Dunlop]

This Sender seems to give up its mysteries just as readily as revealing new ones to sort out. After careful removal of the 25 panel screws I had previously identified, the front panel was still firmly secured across the mid-section of the chassis. It was then that I realized the upper corners of the Flick Drive Assembly Boxes are also secured to the front panel. By the same screws that serve as the setscrews for the PLATES, Stop, No. 1. In realizing that, it suddenly made sense why the sixth such PLATES, although not installed at the far right side of the panel, still needed the lone setscrew fitted. That mystery now solved, but I still need to sort out why the PA TUNE only required the one, left hand PLATES.

Once those six screws were removed and secured, the Sender front panel lifted clear of the chassis. As usual, several panel screws are missing lock washers and one for certain is oversize. Several are also longer than they need to be. I suspect if any were damaged at some point, the easiest replacement was used rather than getting the proper length. Note to self to find appropriate replacement screws for reassembly.

The two INDICATORS are top heavy when freed from the front panel and swing on the gearbox as a result. I think it should be fairly easy to get the left one set to ‘0000’ prior to putting everything back together.

The really good news was with the middle Flick Drive Assembly. The retaining spring for the two Flick Arms had indeed disconnected from the Lower Arm and as a result, the Lower Arm had fallen away from the Flick Control Shaft. You can see the Lower Arm lying above the shaft in the second photo.

The paint on the right hand Flick Drive Indicator Flags is factory original and in very good shape. When exposed to light for a while and then put into darkness, the upper white sections of the two flags glows bright green. The white on the other two sets of flags has been painted over at some point with a plain flat white paint that did not adhere well to the underlying luminous paint. It has all blistered and lifted. In the dark, only the outer edges still show a slight glow and you can see where the newer paint was applied in large gobs with a brush. I now have a supply of the correct luminous paint so these two sets of flags will get a repaint.

Pretty good access overall for getting at internal chassis components fro a good cleaning now.

Have to take a closer look at the broken panel screw on the right side upper chassis rail now as well, to see how best to remove it.

David