Wireless Set No. 52 Canadian - Project

[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

[David Dunlop]

Rod.

I was about 4 years old when I first introduced myself to the exciting world of electricity.

My parents had given me a Punkinhead desk lamp for my room, which always had to be on when I went to bed. For some long lost reason one day, I decided I wanted to cut the plug off the end of the cord. I knew enough that the cord would be a tough cut but I was sure Mum's prized Sheffield Steel Dress Making Shears would be up to the task. I also figured I would need both hands on the shears to be successful, so leaving the plug in the wall socket seemed a logical thing to free up both hands. I had also thought through that since I was making sure the lamp was turned off, no electricity could possibly be involved in the activity.

The flash and the bang were spectacular! A funny tingling raced up my arms and the shears went flying to the back of the room and a scorched metal smell lingered in the air. When I retrieved Mum's shears, a neat arc had been burned out of one of the blades, the same diameter as one of the cord conductors. Needless to say, putting them back where they belonged and playing dumb and stupid didn't work.

Cheers,

David

PS: I am betting that lamp would be worth a fortune today in original condition.

[David Dunlop]

I found this 7mm rubber cased HT ignition cable on line and ordered 10 feet of it to fabricate one of these LEADS. It has the correct stranded copper core and a nice high heat rating. The silver ID labelling along the cable also comes off nicely with a solvent I have, so a little progress on that part of the project now.

David

[David Dunlop]

An interesting development over the weekend.

I completed the required Voltage and Resistance tests on the Remote Receiver, which have provided some interesting information. I also finally pulled all the valves from the Remote Receiver to run them through the tester.

You may recall that at the time I acquired the three 52-Set receivers, I had no means of testing the British based ARP-3 and 12Y4G valves, so simply cleaned and visually inspected them all, cleaned the sockets and put each valve back where it came from.

So now the ones in the Remote Receiver all came out again and each was given an ID tag. Of the eight ARP-3’s in the receiver, the V1C (Mixer) was totally dead and another, the V1G ( 1st AF Amp), was so weak as to be useless, so both were replaced by good ones from my parts receiver.

The real surprise was the two 12Y4G’s on board. Both V2A (Detector/AVC) and V2B (Noise Limiter) were completely dead on both sides internally. Not even the slightest glow in the dark from either after 20 minutes of receiver warm up. When I pulled the easily accessed 12Y4G from the parts receiver, it too was completely dead on both sides.

That seems like an extremely high failure rate for a valve and it has now got me wondering what kind of a reliability record these 12Y4G’s had in service use.

David

[Bob Carriere]

Lots of the work you are doing is way over my head....but if those valves have been fried....so many of them...... could there be something else that "blew" them out......and could you be risking the new tubes you are planning to put in? ............ dried up capacitor...... any physical damage that could cause a ground....... Just curious!!!!

Too cheap to buy a proper static bracelet when working on my computer to eliminate any static charge I might build up................. so I wrapped a light piece of copper wire to an overhead water copper pipe in the basement computer room.......with the other end loosely tied to my left wrist..... until some one reminded me that if I accidentally touched a 110 v wire......I might just fry myself with a "dead ground" around my wrist........ I do have a proper voltage limiting bracelet now.......

Cheers