Wireless Set No. 52 Canadian - Project

[David Dunlop]

I covered off the improvements to these DRIVES that CMC made when I was restoring the Sender last year. You can definitely feel the difference in weight between these assemblies and the ones in the Wireless Set No. 19 once they are free from the chassis. Better quality parts, higher machining standards and more reinforcement would have gone a long way in reducing the physical wear which resulted in sloppy tuning stability.

And it makes sense when you think about it. The intent of these DRIVES was to allow the Operator to pre-set two different communication frequencies – typically a day and a night frequency, so these drives had the potential of being swung back and forth, stop to stop, at least twice a day. No wonder one of the frequent complaints CMC got from Operators was the loss of ability for the Drives to reliably move to frequency repeatedly, over time.

The frame of these Drives is slightly thicker than on the 19-Set Drives and you can clearly see the solid, bronze alloy triangular blocks CMC used to stiffen the top outer mounting corners. On the 19-Set Drives, these corners were simply created by bending the frame sheet metal over in these areas.


David

[David Dunlop]

This Couplings connects the shaft at the back of the DRIVES assembly to the shaft at the front of the Tuning Capacitor, directly behind the Drives in the chassis.

At first glance, it looks very much like a simple coil spring assembly, but in fact; it is a thin sheet steel bellows construction. Note there is no ‘coil’ present, just a parallel set of ‘rings’.

A collar is fitted at each end and each collar has three 8-32 Grub Screws set 90 degrees apart to secure the Couplings to both shafts it connects. These bellows remind me of the much larger ones found in fancy aneroid clock work barometers from days gone by, only they were typically fashioned of copper or brass, back when scientific instruments were works of art.

Interestingly, when I removed this coupling, I marked the two shafts to see where the Coupling actually was mounted. I am glad I did. Nearly 5/8-inch of shaft was under the Coupling at the DRIVES end but with less than 3/16-inch under the Tuning Capacitor shaft end, the grub screws were barely hanging on. Something to be wary of if I am ever servicing one of these parts again, down the road.


David

[David Dunlop]

This is quite an impressive wiring harness when you finally see it out of the 52-Set Receiver chassis. The perimeter rectangle for it in the photograph is 16 inches by 24 inches, and it would have been a very interesting workstation on the production line to watch in action.

I wonder how many of these harness looms would have been assembled in any given work shift?


David

[David Dunlop]

This is the only other free standing wiring harness in the 52-Set Receiver. In the photo, it sits within a 9-inch square.

It is found on the lower left front of the chassis, connecting the A.F. GAIN, NOISE LIMITER IN/OUT and HET. TONE Switches to their relevant circuits on the back and bottom of the chassis.


David

[David Dunlop]

This particular switch in the 52-Set Receiver wins the award for the longest switch shaft.

Its location on the underside of the chassis can be seen in the first photos of both Post #619 and Post #620 .The terminal wafer assembly on the switch is located at the back of the lower chassis, supported in place by a mounting plate that forms a part of the frame for the switch. The holes in the lower front of the chassis and lower front panel plate support the front end of the shaft. Total length of the shaft is 9-1/4 inches.

This is the SHARP FLAT Switch in the receiver circuits.


David

[David Dunlop]

This is the shorter relative of its 5.5-inch cousin I covered in Post #617 and is of identical construction. In fact, it is the description of this CONNECTIONS, Screened that confirms how both are put together such that the wire does not make contact internally with the tube.

An appropriate length of the tinned, solid copper wire is cut and a small bead of solder applied at the required distance in from one end and a ceramic end cap dropped in place down the wire. Ceramic fish beads are then added down the wire in sufficient number to fill the metal tube. This wire and bead string is then slid into one end of the tube and pulled into place. The ceramic end cap is added to the open end of the string and a small bead of solder added at that end to secure and complete the assembly. The ceramic fish beads inside the tube are small enough let the wire down the middle of them flex with the curve of the tube, yet stay centred in the tube.

In the second photo of POST #619, you can see this CONNECTIONS, Screened tucked in between the two long rectangular banks of coil/caps, at the right hand side of the gap.

David

[David Dunlop]

The next phase of this parts receiver disassembly is going to focus on the removal of the 3-Gang Tuning Capacitor and the Coils Assembly, RF, mounted directly above it. These two units take up most of the right front half of the receiver. I still have a few bits to think through before I forge ahead.

If you refer back once again to the 2nd Photo in Post #619, this is a view of the back of the receiver chassis, with the chassis resting on its left side. The upper centre section, with the nine evenly spaced access holes is the back of the COILS ASSEMBLY. The back end of the 3-Gang Tuning Capacitor, with its curved top and big splotch of red paint, sits directly to the left of the Coils Assembly. Three leads from the Coils Assembly still run to the V1A, B and C sockets to the right side of the photo. These leads need to be unsoldered from their valve socket terminals.

The photo attached today shows these two components from the front of the receiver chassis. From what I can see so far, there are five leads running from the lower Tuning Capacitor up into the Coils Assembly. All these appear to be solid wire leads and may prove a bit tricky to get at with a soldering iron. Then there is the need to track down where all the mounting hardware is and sort out its removal.

You will notice in the attached photo, the INDUCTANCES, RF (L10A) is mounted to the bottom section of the Coils Assembly and actually extends down, in front of the Tuning Capacitor. This is the large disc, roughly centered on the Coils Assembly. This means the Tuning Capacitor had to be installed on the chassis before the Coils Assembly went on. Interesting.

On the front of the finished receiver, L10A shows up as the FREQ. ADJ. Knob.


David