Wireless Set No. 52 Canadian - Project

[David Dunlop]

Thanks for the information on the grease, Chris. You are right...best not mix it up with the spices.


David

[David Dunlop]

I had to take a break from oscilloscope work this week as my head was starting to spin, and I think I was also developing a mild case of 52-Set Withdrawal.

I decided to try a little more hand polishing to remove more of the yellowed varnish top coat on the Sender panel. A simple half hour of freehand work without work lights. I tackled the lower right quadrant of the sender fan door assembly, where I had earlier removed a set of red numbers. (See Posts 201 and 228).

The polish cloth was coming away with quite a brown tone to it as I worked, but the colour did lighten up quite a bit and when the time comes to clean the Sender panel, I think I should be able to get a very close match to the upper portion of the Receiver panel.

The other little bit of excitement was the arrival yesterday of a second Cases, Spares Box for the 52-Set.The interior KimPaK lining in this one is as close to mint as one could hope for, compared to my other box. (See last photo Post 168). Restoring/replacing that lining was going to be a major challenge, so I was pleased to cross paths with this one.

This box also underwent a NATO conversion on the outside and I will be surprised if any original stencil markings show up. But I will take a careful look...just in case. The exterior of the box was sanded and NATO Greened, and then a large patch of tan paint was slapped on and NATO stencil ID's added in black. It looked so garish, the previous owner toned it down with a uniform coat of green paint.

David

[David Dunlop]

This assembly is missing from the Slow Motion Drive on my Sender P.A. Drive Dial. I have been able to source an example of the earlier version from a 19-Set Mk II, which I can install to get the dial controls operational, but I would eventually like to find the correct later version of this assembly.

The early (Mk II 19-Set) version is a single leaf spring item. With hard use, these were found to weaken over time so on the 19-Set Mk III Canadian, and the 52-Set, a reinforced version of the assembly was introduced. It can be recognized by the addition of a second half leaf piece of spring steel riveted at the base end pivot point.

If anyone happens to have a junker Mk III Canadian 19-Set with one of these reinforced assemblies available, please let me know.

David

[David Dunlop]

The oscilloscope sub-project is now officially on the back burner. I have been able to bring it back from a disassembled hulk to a working scope, even if, at the moment ‘working’ is not yet exactly as per design.

Having been away from the 52-Set Project for almost two months is enough time away. I pulled out the 2nd to 4th Echelon Repair Manual and started rereading it today. With a little luck, I should be able to align and calibrate both receivers, without having to sort anything serious out with a scope.

I do like the approach of the individuals who wrote the repair manual. They start you off nice an simple. Step 1 is to zero the indicator needle on the meter and calibrate the meter. So off we go! I will continue to post as things unfold.

David

[David Dunlop]

Well I am finally catching up a bit on this project, but not without a fair amount of multi-tasking. Something I have never been very good at for long, without getting a major headache in the process and a large empty space in the wine cellar (for which I deny any correlation whatsoever).

The first thing I realized was the documentation of work in the 2nd to 4th Echelon Work Manual is comprehensive, but not organized in the best manner for actually recording test data results. Five tables of specifications relate directly to the 52-Set Receiver as follows:

Table 7 - Receiver Voltage Check
Table 8 - Receiver Resistance Chart A
Table 9 – Receiver Resistance Chart B
Table 10 – Crystal Calibrator Resistance Chart A
Table 11 – Crystal Calibrator Resistance Chart B

I have now transcribed the first three tables to Excel Spreadsheet format, adding in spaces for recording actual test results next to each specification. This makes saving the data for later analysis so much more efficient. I hope to have the two calibrator tables finished by next weekend.

In addition, this morning I was able to complete working through the data collection from my Remote Receiver for Table 7. This data is collected with all valves and lamps in their sockets and the chassis powered up. It took longer than I thought, for a couple of reasons.

First issue to arise, was realizing I had been away from working on my 52-Set just long enough to not remember the pin layouts of all the valve sockets, when viewed from the top, or bottom, of the sockets, and once I had sorted Pin 1 locations out, whether the pin count proceeded from that point in a clockwise or counter clockwise fashion. It took about four sockets before it all started to come back to me.

Since all valves are in place and the power is on, the only place to access the socket pins is from below the chassis. That seemed pretty good initially, as all valves except V1G and V1H can be accessed at the back of the chassis. The remaining two can be reached simply by tipping the chassis to either side to expose the bottom chassis assembly. But there is always and exception, isn’t there…and in this case it was two!

V1A and V1B sit quietly in the upper right rear corner of the chassis, directly behind the large Bakelite 8-pin Connector Socket. There is no way around it. The three small screws holding the connector backing plate to the upper right rear corner of the chassis have to be carefully removed and the Connector Socket assembly guided gently away to expose the two valve sockets beneath it.

That’s when the second issue surfaced. Once I was satisfied the Connector Socket assembly was safely out of the way of the two valve sockets and no exposed contacts on the assembly were touching anything they should not be, I turned the Remote Supply Unit back on. No Pilot Lamp and no Low Tension showing on the meter. My first thought was I had broken one of the wires on the Connector Socket, so carefully checked them all. They were fine. Then I remembered, the ground for the socket is through its backing plate being mounted to the receiver chassis. A quick addition of a jumper cable between the chassis and the backing plate and on came the Pilot Lamp and 12 volts showed on the meter. Data collection from the Remote Receiver for Table 7 has now been completed.

David

[Rod Salter]

David,

I once discovered the "No Earth" problem as yours was, by this method

Imagine if you will, late in the evening hot and sweaty in a cramped area

set is powered on, after market power supply

Probing with a meter

decide to turn the thing over

one sweaty hand on the chassis, reach the other sweaty hand to support the connecting cable

"WACK"

full HT through the chest and both arms

Problem diagnosed

The outer shielding had become detached from the plug

I can't remember what the set was, maybe some sort of drive in theater audio amplifier
but I remember the incident vividly!

Side note - the particular drive-in had all 110 volt equipment, patched to 240 volt operation
It was a steep learning curve
How did I come to be there - apparently one look and no one else would touch it, this I was told much later, and here I was all bright and innocent thinking "How lucky I was to get the job"

cheers rod ps no laughing please

[David Dunlop]

Thought I had better document this bit of information while I am researching the construction of the LEADS, Aerial 25-3/4 inches long, No. C1, that fits between the Receiver and Sender sections of the 52-Set.

On both components of the 52-Set, the terminal pins on each end of the LEADS, fit into the TERMINALS, Aerial, No. C1 mounted on the upper portion of the front panels of the Receiver and Sender units. Figures 1 and 2 in the WORKING INSTRUCTIONS for the Wireless Set No. 52 show the LEADS properly installed and are worth a close look.

“Paragraph 2.1.2 Interconnections”: comments on this LEADS assembly noting that the insulated terminal end of the LEADS is the Receiver end of the LEADS. It will be noted, this is also the end of the LEADS where the yellow ID sleeve is fitted over the LEADS. The addition of the insulation over the terminal pin sleeve at this end, along with the extra thickness of the yellow ID sleeve, probably make the LEADS less flexible at this end and the insulated terminal may not even be able to pass through the eyebolts along the top panels of the Supply Unit and Sender. I have yet to see a real LEADS to know for certain, but the comments in the manual suggest this is quite possible. The LEADS come off the TERMINALS, Aerial assembly on the Receiver in a large gentle clockwise curve before heading through the partition holes and eyebolts. At the Sender end of the 52-Set, the LEADS feed out the last eyebolt and angle at a “10 - 4” line, straight into the TERMINALS, Aerial.

The insulation on the Receiver end of the LEADS puzzled me at first, until I realized the LEADS is not a modern coax cable. It is a classic single conductor cable and the pin terminals at each end are one-piece items. Once the pin terminals are soldered on, they become charged when the 52-Set is in use. No big deal at all at the Sender as no controls come close to the TERMINALS. Aerial to put the Operators pinkies at risk. It is a different matter at the Receiver end of the LEADS.

On the Receiver, the TERMINALS, Aerial is fitted just to the right of the FREQ. ADJ. dial, right where an Operator’s fingers would have a really good chance of making contact if using the FREQ ADJ.

I mentioned above that the LEADS comes out of the eyebolt on the Sender and heads straight towards the TERMINALS, Aerial assembly in a “10 -4” line, if one is looking at the face of a clock, centered over the TERMINALS Aerial. The slot in the TERMINALS, Aerial must also be turned to line up in a “10 – 4” orientation for this connection to be made. Something to be aware of.

The attached photos show in order:

A: Remote Receiver sitting at "12 - 6" (To be adjusted.)
B: Main Set Receiver at “11 – 5” (to be adjusted.)
C: Spare Parts Receiver at a correct “10 – 4” position.
D: Sender slightly beyond “12 – 6”. (To be adjusted.)
E: This is a reference view of the rear mounting on the receivers for the TERMINALS, Aerial. As you can see, it also serves as the mounting for the right side retaining clip for the ARRESTORS, Protecting, Gas Gap.


David