Wireless Set No. 52 Canadian - Project

[David Dunlop]

As well as its more formal name, this component is also known as the Audio Output Transformer, with a Circuit Reference Number “T1A”.

It is mounted to the side of the chassis, in the lower, front right corner (upper left section of the 1st Photo in Post #620), held in place by four slotted, countersunk machine screws, with external tooth lock washers and hex nuts.

Interestingly, the two rear sets of hardware had thick, spacer/washers between the transformer case and the lock washers. They were serving no useful purpose there, but were the same thickness as the chassis metal. The transformer sat firm and flush to the front chassis, but perhaps at one point in early production, where was not enough clearance for the transformer to fit flush, so spacers were used to give it clearance on the chassis. The spacing issue was resolved but the spacers were never dropped from the production process.

The stamped part number on the transformer case faces out, to the right side of the chassis when installed, with Terminals 3. 4 and 5 on the transformer panel facing the front of the chassis. The transformer appears to be of Canadian Marconi design and manufacture, based on the Part Number Stamp on the side of the case.

The side of the transformer case facing to the rear of the receiver chassis has a pink stamp on it stating, “O.K. TO FILL”.

On the top terminal board of the transformer, the CMC Part Number is repeated, directly above the one stamped on the side of the case. Roughly dead centre is stamped the Circuit Reference Number “T1A’. Stamped in the large space above ‘Terminal 1’ is another large, pink square stamp stating, “TESTED O.K.”, with a round, black CMC Inspection Stamp over top of it.

David

[David Dunlop]

In terms of the 52-Set receiver circuits, this component is the R.F. GAIN CONTROL, Circuit Reference ‘R33A’.

The original manufacturer was C. G. Meredith & Co. Ltd. but I have yet to find anything about them on the web. Probably a long gone company by now.

David

[David Dunlop]

These small CLIPS are one of the simplest designed parts of the receiver so far, but potentially one of the more interesting to sort out when it comes to the assembly work process.

They are used with the eight ARP-3 Valves in the receiver, the V1-Series of valves. All of these grid cap leads are single lead items feeding directly to a contact point on a socket, coil base or Tag Panel.

These two CLIP Leads came from the V1G and V1H ARP-3’s (the only two vertical ones in the receiver) mounted on the lower front left chassis floor, and went straight to a Tag Panel. They feed through a 0.199-inch diameter hole in the chassis floor that is lined with a metal eyelet, to prevent cutting of the lead insulation. As you can see, these holes are located just to the left of the rear socket rivets. A third, similar CLIP lead is located on the upper left back chassis panel next to the socket for the V1F ARP-3.

With each of these three CLIP assemblies, the clip has been soldered to one end of the led, a small yellow sleeve slid up over the soldered end of the clip and the sleeve carefully tied in place with one round of cotton cord. The end of the sleeve over the soldered connection was then lacquered. The sleeves are there to protect the lead insulation from chafing against the slots cut into the valve shield caps through which these CLIP leads pass.

It would make sense, with limited space to work in the chassis itself, that these CLIPS leads were preassembled and delivered to a station on the line for addition to the chassis at an appropriate time.

Similar CLIPS are used for ARP-3’s V1A, B and C across the upper front right rear of the chassis. These three are the shortest Clip leads in the receiver and they were added to the circuits as complete assemblies because the upper shield plate protecting the RF Coil Assemblies has three oversized holes in it to allow the Clips to easily pass through the plate when it is screwed in place, or removed. These three Clip leads, however, have black sleeves fitted to them. Reason unknown at this point in time.

The last two CLIPS are used with ARP-3’s V1D and E and these two leads feed out from inside the respective Coil Shields directly below each valve. The holes these two leads pass through are also 0.199-inch diameter, lined with metal eyelets.

It will be a little while yet before I am ready to remove these coils and shields to be able to have a look inside at the assembly work.

David

[David Dunlop]

The location of this part can be seen in the first photos of Posts #619 and #620, directly below the T1A Transformer.

The Circuit Reference for this resister is ‘R14A’ and it is the Meter Adjustment used for calibrating the Meter. It is reached by means of the long slotted screwdriver in the Tool Kit from directly above, between the Flick Drive Assembly and the Tuning Condenser. The adjusting slot is visible immediately to the left of the Flexible Tuning Drive Coupling, when you look straight down in that location.

It appears to be another ‘in house’ CMC product, with its CMC Part Number stamped into the rear cover of the resistor case, ‘115-294’.


David

[David Dunlop]

This JACKS assembly is oriented vertically in the lower right front corner of the receiver, with Circuit References J2A and J2B.

I have left the SWITCHES, Toggle, DPDT No. C3 (ZA/CAN 4669), circuit reference S4A, still attached for future reference.

The first photo shows the two components more or less oriented as they are on the chassis. Approximately three inches of the lower chassis plate are bent down to form the lowermost front wall of the receiver chassis. The Switches along this three-inch strip all mount directly to the chassis and the lower front receiver panel has large enough cutouts to drop down over the mounted stitches.

The JACKS, Telephone, on the other hand gets installed along with the switches, but is not mounted until the lower receiver panel is in place. External tooth lock washers sit between the front face of the JACKS assembly and the back of the lower receiver chassis plate.

The second photo shows the side of the JACKS that faces to the interior of the chassis: towards its SWITCHES S4A located immediately to the left of the JACKS. The body of the JACKS is cast Bakelite and two slots on the inner face hold the two spring metal contact strips that secure the Phone Plugs when inserted into the JACKS. The retaining hardware for these two springs also serves as the mounting points of the electrical leads to the JACKS.

The last photo shows the side of the JACKS facing to the outside right of the chassis where the mounting hardware for the two contact strips is secured with an internal tooth lock washer and a pair of hex nuts each fitting.



David

[David Dunlop]

This is the last of this type of switch used in the 52-Set Receiver. This is the TONE FILTER Switch, located on the lower left front of the receiver, between the Mode of Operation Switch and the Meter Switch. Its circuit reference is S4C.



David

[David Dunlop]

The full Nomenclature for this component is, SWITCHES, Rotary Disc, SP, 12-Position, 2-Bank, No. C1, and its circuit reference is S3A. It is more commonly known as the ‘Meter Switch’.


David