Wireless Set No. 52 Canadian - Project

[David Dunlop]

I have been taking a bit of a break from receiver work today and taking a closer look at the Carriers No. 4 assembly to better sort out the work it will need down the road.

While Jacques Fortin had been keeping watch over the set for me prior to shipping it West, he had noticed all three components took a bit of grunt work to get in and out of the Carriers. A large part of this was attributable to the shear weight of at least the Supply Unit and Sender bearing down on the painted interior surfaces of the bottom of the compartments. Any dirt on the bottom chassis rails of the components really dug into the paint and there was no sense of 'slide' whatsoever. My short term thought on this is to strip the paint chemically from the bottom of the compartments to hopefully reveal the original factory satin nickel plating.

The other point of concern ws the snug fit of the Receiver into its compartment along the sides. While taking a closer look at this issue today, I discovered the left side panel of the receiver compartment bulges into the compartment right at the point where the left side mounting screw locates. I at first thought the problem was an overtightened screw at some point in time that drew the side panel in, but a close look suggests this is unlikely. The mounting screw passes through the side panel skin and starts threading into the steel reinforcing bar located around the outer edges of the panel. It then continues into the front guide bar assembly for the retracting carry handle which takes up all of the load of the screw. Looks like it should be an easy fix, however. Next time the receiver is out of the Carriers, I should be able to tap the bulge back flat to prevent the panel from binding on the receiver mounting bracket and upper panel assembly.

David

[David Dunlop]

I am not sure how large of a sub title these individual posts can handle, so I will start by providing the full description ID of this part as follows:

BLOWERS, Electric, 4-Blade, 3-inch, 12 V, 1.2 Amp No. C1 ZA/CAN 4411

One each of these are located in the upper panels of the Supply Unit and Sender of the Wireless Set No. 52. They are thermistor controlled, only coming on when the internal compartment temperature rises to a preset point, either from excess ambient air temperature, or excessive dynamotor operation. I suspect they are set up as exhaust fans, but that has yet to be confirmed.

While I was in the mood to explore the fan in the Sender more closely, I hauled out the trusty warm soap water and toothbrush to clean off the grime on part of the rear of the fan assembly. I deferred use of any chemicals as the two horizontal electrical components seen lashed to the rear of the fan motor looked very much like wax coated capacitors. I was 50% correct. The forward one was indeed a .1 microfarad 500 Volt cap, C3AF in the schematics. The rear cylinder, on the other hand, turned out to be the small R.F. Choke (L30B) to suppress noise from the fan motor and it was tucked neatly into a small plastic tube.

While not yet a comprehensive cleaning, it did confirm a pair of CMC inspection stamps on the back of the fan door assembly, and another pair on the rear face of the lower phenolic resin board on the lower half of the motor, The name “REDMOND” also showed up stamped on the back of the motor case, just below the rear bearing cap assembly.

David

[David Dunlop]

I connected a 2 Amp 12 Volt supply to the Blower in the Sender this morning and both fans sprang to life nicely. Very quiet operation and the amount of air they can pull out of the Supply Unit and Sender would be very effective, if needed.

They showed no wind down at all when the power was cut off, which could be by design, or more possible, they have seen little or no use over 75 years so are essentially brand new with no lubrication for at least 50 years. Time to see what the publications say about fan maintenance.

David

[David Dunlop]

Work on the receivers is now on hold, pending arrival of a supply of needed spare valves, so I am switching to the Sender, in order to start giving it some much needed TLC. It is a sad looking bit of kit at the moment, but the front panel is going to be the much easier task to undertake, and will have much more visual impact when finished (whenever that turns out to be).

The vast majority of paint chip damage to the Sender has happened around the edges of the panel and in a few spots, I will have to wick glue under the lifting paint to secure it from further damage. I am hoping that once the staining in the varnish has been polished down to the desired patina, the damaged paint around the edges will become less noticeable. The front panel of the Sender is so chocked full of knobs dials, buttons and switches, the eye gets naturally drawn away from the outer edges and the paint chips tend to disappear into the background shadows. The damage is not at the point where it detracts from the Sender and keeping it adds confirmation this 52-Set had a working history.

Apart from the paintwork, this Sender has very little other physical issues discovered so far. The four attached photos cover off what I have found will require some attention, and only one is currently of concern.

The first photo is of roughly the upper right quadrant of the panel. A panel mounting screw has had its head snapped off, directly above the BAND Switch. The screw shaft is exposed behind the chassis, but next to impossible to access to try turning it all the way out. It will likely become a candidate for being carefully drilled out. It is one of those small, split tip self threading items that also shows up in the assemblies of the 19-Set so should be an easy item to find replacements for from some of the bits I have on shelves as spares.

The critical repair also shows up in this photo. It is the COUNTERS, 0/9999, 2-3/4 inch x 1-3/8 inch x 1-7/8 inch, No. C1 ZA/CAN 4642, which is the small, four-digit dial indicator for the 7 – 16 MC PA TUNING assembly. As you can see, the indicator shows ‘0,0,0,4/3’ with the dial brought all the way back to its starting point. It should be showing ‘0,0,0,0’ at this point and I will have to figure out how to zero set it eventually.

The second photo is the upper left quadrant of the panel showing how badly chipped the paint is on the Blower Fan Cover. No way around it, that item will have to be removed, cleaned up and repainted. Way too much bare metal now showing on it.

The third photo is the lower left quadrant and the only thing going on there at the moment is another split type panel screw that is completely missing.

The last photo is the lower right quadrant where the Slow Motion Drive for the PA TUNE dial is missing critical parts, which I now have a suitable temporary replacement.
Another bright note, I have discovered the cabinet lock for blocking High Power Mode on the output power switch, is not frozen. Just need to track down keys for it eventually.


David

[David Dunlop]

This is the formal name for the two four-digit indicator dials on the 52-Set Sender PA LOADING Dials and the Coil, Aerial Tuning Assembly.

As the name of the item notes, these Counters are capable of reading from a Zero start point all the way up to “9,9,9,9”, if they need to. As far as the 52-Set is concerned, none of the three Counters come even close to their limits at their respective top ends.

The error on the 7 – 16 MC PA LOADING Counter on my Sender is high when it is back at its Zero Point. After thinking about it for a while over the evening yesterday, I realized the only way that could have happened was at the top or upper limit of travel for this Counter, but I had no idea exactly where that upper limit would be, for ANY of the three counters used with this wireless set. And none of the manuals reference that limit information either. The only way the misalignment of numbers could have happened, given the design of the system, was if somebody had rapidly spun the dial up in a very aggressive fashion and when the upper stop was hit, the angle drive at the back of the Counters flexed enough for the gear set to jump a few teeth, pushing the numbers up three and a half digits higher than the indicator should have gone.

So I took the time last evening to run each dial up to its upper limits and recorded the results as follows:

7 – 16 MC PA LOADING: 0,4,4,9/8 *
1.75 – 8 PA LOADING: 0,7,7,8
COIL, AERIAL TUNING: 1,2,9,6

* Given this COUNTERS is now reading 3.5 digits high, the correct upper reading should likely be ‘0,4,4,5’


Thought I would post these results in case anyone else needs to know.


David

[David Dunlop]

Here is a photo of the back of the Counters for the 1.75 - 8 PA LOADING Coil. It is the only one in the set that is readily visible at the right side of the Sender Chassis The incorrect one, unfortunately, is inboard of this one and next to impossible to view/access without major disassembly of the Sender.

You get a good idea of how the angle drive operates and relates to the main shaft of the coil assembly, however, and all three would have an identical setup.


David

[David Dunlop]

This little bundle arrived in this afternoon's Post. 12 NOS Canadian Marconi Company (Radiotron) 12Y4 Valves in minty, original wartime packaging.

David