Wireless Set No. 52 Canadian - Project

[David Dunlop]

Well this part of the project is going to be full of challenges.

I need to get the Blower Motor assembly for the Supply Unit out of the way to gain access to the hardware set causing the case for the Vibratory Supply to jamb in its tray. I studied the blower for the better part of half an hour looking for an easy way to remove it. There are none. The blower assembly and its related Covers were definitely installed on the front panel of the Supply Unit before the panel was installed on the Supply Unit chassis. Then its power feed wire was soldered in place. In situ, there is not enough room to easily get even the smallest tool onto any of the Covers hardware to remove it. You can loosen it all but end up resorting to fingers to ease the hex nuts out. A small shop magnet on a telescopic stick helps, as does a small pair of needle nose pliers. But even with all that, I still dropped one hex nut and one lock washer into the innards of the Supply Unit. Fortunately, they both dropped to the bench when the supply was carefully turned upside down and I knew what two sets of hardware the bits came from. Still interesting for what is intended to be a temporary disassembly.

Once off, the Covers was actually in better shape than the one on the Sender. The screen was popped inward (as was the one on the Sender), but no screen wires were broken and the screen pressed back flat with a little gentle thumb work. The rust accumulation on the inside of the Covers and the Blower Fan Blade is about the same as on the Sender Blower. I think dust settles inside the Covers, and static clings to the fan blades. Over time, this dirt accumulation attracts moisture and then rust settles in on the surfaces. Also, the inside surface of the Covers is primed only. There is no Gloss Navy Grey topcoat inside there at all.

The large pieces of front panel paint missing inside where the Covers sat had actually peeled off and curled up into tubes inside the Covers and the red oxide primer on them confirmed the paint was from the 1966 rebuild.

That was enough excitement for this evening. I shall study and plan for the next step tomorrow.


David

[David Dunlop]

Unlike the grub screw on the Sender Blower fan, the one on the Supply Unit fan was well and truly seized in place.

Two days of soaking in sewing machine oil, lots of hand tapping on the fan hub with a suitable sized punch and I was able to pop the grub screw free and into about a one-quarter turn mode, back and forth. Another day of soaking and I was able to slowly work the grub screw back and forth more and more this morning until it came out of the hub completely.

A soak with Deoxit this time and I was able to drift the fan back and forth on the Blower Motor shaft to within an eighth of an inch of coming off completely. I then took an old, dull half-inch wood chisel, and with the blade resting on the shaft and the flat of the blade against the fan hub, I was able to tap the chisel head with a small hammer and pop the fan off its shaft.

This should make removal of the Blower Motor assembly from the Supply Unit a lot easier.


David

[David Dunlop]

Two good evenings in a row working on the Supply Unit

Yesterday I disconnected the power lead from the Supply Unit Blower Motor (Photo 1) and undid the three mounting bracket screw assemblies that hold the motor to the front panel of the Supply Unit. Exactly the same process as for the Blower Motor on the Sender, but with more limited access to the hardware in this case.

If you are planning on doing this work at any time, I would suggest you place a small sheet of paper towel underneath the Blower Motor to catch falling hardware: hex nuts, lock washers or flat washers. When they drop, they are a lot easier to retrieve on a white paper towel than when they dive deep into the bowels of the chassis and hide among all the other shiny, metallic bits and pieces.

As hoped, once the Blower Motor was out of the way, I had a good view straight down the right side of the Net Switch, at its back corner near the large metal coil box to the round head slotted screw I needed to get a screwdriver on. Once the screw was captive, I carefully tightened the hex nut and did a test fit of the case for the Vibratory Supply. It cleared the hex nut nicely, but hit the screw head on. This was a replacement screw for some reason and it was 1/16 “ to 3/32 “ too long. About ten minutes careful work with a large flat file, with a large piece of paper towel on the tray to catch all the filings, and the screw was flush with its hex nut.

Another test file of the Case this evening and it slid easily all the way back to its spring clip. A nice way to end the week.


David

[David Dunlop]

I realized after my last post that I had neglected to give much detail on how I actually removed the Blower Motor assembly from the Supply Unit, so best sort that out now.

The three mounting studs are located top left, top right and bottom dead centre and the hex nuts require an 11/32-inch spanner or small socket. Since there is not a lot of room inside the chassis to swing a spanner effectively, my tool of choice is a ¼-drive socket drive, which I use just to crack the hex nut loose. Once loose, I resort to just the socket with my bare fingers to back the hex nut to the end of the screw. I then use my fingers alone to remove the hex nut, keeping the lock washer well out of the way. With the hex nut out of the way, I then use a small slot head screwdriver to nudge the lock washer far enough down the screw shank to be able to grab the edge of it with a small pair of needle nose pliers and remove the lock washer. There is no lock washer on the mounting screw assembly in the upper right corner of the Blower Motor assembly. Electrical grounding braids terminate here on a large Shakeproof Tag, which serves as the lock washer. With the lock washers and Tag out of the way, the next item to be removed is a flat washer. It may stick a bit to the rubber grommet style shock mount behind it. If so, a small blade screwdriver will pop it loose and the same removal process as used for the lock washer works well.

I generally leave the three long mounting machine screws in place up to this point. As the hardware is loosened, the weight of the Blower Motor holds the screws in place quite nicely. I start with the lower mounting hardware, go to the upper right set and finally the upper left. While holding the Blower Motor with one hand, I remove the three screws in the same order. To remove the assembly, I moved it straight back into the chassis and swing it to the left as the fan shaft at the front of the motor clears the front panel. This will bring the Blower parallel to the inside of the front panel, with the fan shaft facing the large opening on the right side of the Supply Unit chassis. You can then angle the Blower down slightly as you bring it out the right side to ensure the Phenolic Panel assembly on the back of the blower clears the chassis upon removal.

Sorry I missed all this originally.

David

[David Dunlop]

Although the Blower Motor assemblies for the Sender and Supply Units of the Wireless Set No. 52 are fundamentally identical, they cannot be directly swapped from one component to the other because their respective tag panels fitted to the backs of the motor housing are different.

The blower assembly in the Sender is centred much lower down on the front panel than the blower assembly in the Supply Unit. As a result, there is less clearance above the blower assembly in the Supply Unit to mount any other components.

Each Blower Motor Assembly comes fitted with its own Hash Suppression components for when the fan is operating. These consist of a small RF Choke Coil and a Capacitor. In the Sender configuration, PANELS, Phenolic, 3-Tag, 2-3/8” x 2-1/4” x 1/16” (ZA/CAN 4591) is employed. It is tall enough the large capacitor can be mounted across the front of the Panels above the Blower Motor housing and the smaller RF Choke Coil directly behind it.

With less space in the Sender to work with, Canadian Marconi placed both hash suppression components across the back of the Panels; the capacitor directly above the coil. The circuit references in the Supply Unit for these two parts are C3AJ and L30A and the Panels, Phenolic, 3-Tag, 2-3/8” x 1-3/4” x 1/16” is ZA/CAN 4521.

When I was studying the Blower Motor assembly in the Supply Unit prior to removing it, I had noticed the upper right corner of its Panels, Phenolic, 3-Tag was sitting quite a bit higher than on the left. When I was cleaning the dirt off the blower motor yesterday, I found a large black dash on the top of the mounting strap and this ‘dash’ was located to the right of the large central wiring grommet in the top of the blower motor housing (See photo in Post #805). Looking at this more closely, it appeared that if I loosened the mounting strap enough to turn the dash to centre by the grommet, that might just level out the top edge of the Panels, Phenolic, 3-Tag. I tried it and it worked. So the Blower Motor assembly is now ready to temporarily be reinstalled in the Supply Unit.


David

[David Dunlop]

I was able to finish cleaning the fan blade this morning and it now slides on and off the shaft of the Blower Motor quite nicely.

The two blades that had assumed the lower position while the 52-Set sat idle for years had quite a bit of rust accumulation that showed up as a darker area of small pitting once the blades were cleaned and polished. Whatever company made these fan blades did a very nice job of the nickel plating. It is very heavy duty and has held up well over the years, all things considered.


David

[David Dunlop]

The Blower Assembly and Fan are now back in the Supply Unit for the time being. I just have to resolder the power feed line to the blower, which I will probably do tomorrow.

The Case for the Vibratory Supply is back where it belongs as well.

As I suspected, some fine-tuning of the front panel of the Vibratory Supply was needed to get it to align with the main Supply Unit front panel. I did that by putting the Supply Unit on its back on two pieces of 2 x 4 wood to protect the two 8-Pin Connectors for the Supply Unit and inserting the Vibratory Supply. By backing off the two SEMS Mounting Screws for the front panel of the Vibratory Supply, and the Knobs, Metal, enough wiggle was created in the front panel of the Vibratory Supply I could get it to drop into place correctly and lock the two Shakeproof No. 18 Fasteners and retighten the three pieces of hardware.

Now I can at least see where the restoration of the Supply Unit is headed.


David