Wireless Set No. 52 Canadian - Project

[David Dunlop]

I was finally able to pull my notes together and come up with a logical production process for the tool box at Canadian Marconi Company, taking into consideration they would have focused a lot on as simple a line as possible, that was cost effective and easy to understand.

All three boxes/cases manufactured for the 52-Set by CMC, along with the wooden case for the Coils, Aerial Tuning, are constructed of clear pine. Clear pine boards in large sizes are expensive. You can get around this, however, by getting pine boards cut in smaller sized boards and building them up to the sizes you need. Based on the construction details of the grey Spare Parts Box I found a couple of years back, one could see the tongue and groove details in the smaller pieces of pine used to build the larger panels making up the box.

So once you have a supply of the correct sized boards available, the wood requirement for one box becomes two matched end plates, two matched sides and a pair of top and bottom covers. The ends and sides would be sent through a finger joint maker to have the correct ends of each prepared for gluing and assembly.

The top and bottom boards both have 10 countersunk screw holes drilled around their edges. Two are on each end and three spaced down the long sides. The spacing is identical top and bottom. The most reliable, consistent way for Canadian Marconi to do that would be with some form of gang drill. A board would be inserted and held in place while the gang drill came down and drilled/countersunk all ten holes at once, fast and accurate. These boards would then arrive at the assembly point on the line where they would be glued and screwed down onto the four other finger jointed box panels that were being assembled.

At this point on the line, you would have a whole bunch of wooden boxes with very little extra information to go on. The two opposite sides with the 10 countersunk wood screws around the perimeter would be known as potential tops and bottoms, but fronts and backs could go either way. So in order to remove as much confusion as possible farther down the assembly line, the remaining sides of the toolbox must be readily identifiable. This could all be accomplished at a second well-equipped gang drill station.

At this station, an assembled toolbox would be loading onto the table, with either of the two panels with the 10 countersunk screws in it facing up. Once in place, one set of drills could be lowered to make the four rivet holes for the two hinge straps and the three rivet holes for the two handle brackets, thereby forever confirming the top panel with the 10 countersunk holes as ‘the top’. A second set of drills would come into the front panel and make the four rivet holes for each Latch Assembly and the three rivet holes for the bracket inside the toolbox that holds the tip of the soldering iron. A final set of drill would come on at the back of the box and make the four upper rivet holes for the two hinge straps and the countersunk hole for the machine screw that holds the large bracket on the back wall of the box for the hydrometer case.

At this point, all six faces of the toolbox can be clearly identified, which makes things a whole lot easier down the line.

The next stop on the line would be a band saw station where the box would be loaded such that the saw would be trimming off what will become the lid of the toolbox. Once the two parts are apart, drop the lid into its box and deliver both to the next station. This one took a bit of thinking, but the final clue was in the fact that two of the countersunk wood screws on the back edge of the lid, the countersunk machine screw holding the hydrometer bracket and the 6 finishing nails securing the interior wood partition all have to be filled and sanded down before any riveted hardware is installed, because some of those filled holes get covered with the hinge hardware on the back and lid. If you have to do that fill and sanding work at more than one station on the line, you are not going to be cost effective.

So I suspect that once the box and its lid were two separate items, the next station was where the wooden partition was installed using a spacer block to line it up. The three nails on the front and back of the box are all amazingly close to the centerlines of the edges of the partition. Easy to do with a little practice looking straight down from the top. The vertical placement front and back of each of the three nails are within about ¼-inch of each other. With the wooden partition in place, the metal hydrometer bracket could then be installed, using the top of the partition to get the bracket correctly squared in place.

Filling and sanding of all countersunk hardware could then take place.

There could be some variation in the sequence in which the riveted hardware was fitted, but while still on its own, it would be easy to install the soldering iron bracket and the two lower latch assemblies to the front of the box next.

The handle would be easy to do first on the lid, followed by the rivets securing the two upper latch sections to the front edge and the hinges to the lid. The last and trickiest riveting would be the ones securing the hinge straps to the back of the box, simply because you would now be dealing with working on one big item, in two parts, that want to swing about on the hinge straps.

After that point, the only hardware left to install on the box was the eight metal corner protectors (three round head, slotted wood screws in each), and filling the remaining holes on the hinges and latches with the same wood screws.

Then it would be off to the paint shop for an overall coat of paint inside and out and the addition of the stencil on the front panel. The List of Contents would then be glued onto the inside of the lid, the contents packed and the toolbox inspected and approved for packing.

The attached photos today show the bottom of the toolbox, the front, the top and the back, for reference.

While thinking about this box, I realized how wonderful it would be to find factory packing instructions for equipment like this. I cannot think of how many times I have looked into my Spare Parts Case for my 19-Sets and wondered how they were actually packed at the factory. I know all the bits are there, but it looks a mess and getting it all to fit and look right is yet to be accomplished.


David

[David Dunlop]

This Lamp, Operators No. 2 arrived safe and sound in this mornings mail from Holland.

With luck, it will form a key part of yet another sub-project in my overall Wireless Set No. 52 Project.


David

[David Dunlop]

With any luck at all, this collection of items, along with a few yet to be sorted, will all come together to create a working replica of the actual Operators Lamp for the 52-Set.

It seems the cargo ship full of all the originals has yet to be raised from the depths.


David

[David Dunlop]

I am not certain how many other 52-Sets might be out there being brought back into operational condition. It can be a challenge in terms of available information and every little bit helps.

In getting back to work on my Sender this weekend, I ran across a little oddity regarding the metering circuits in the 52-Set.

On Page 127 of the Operators Manual, there is a Table of Voltage Readings provided for the Sender. For HT1, depending on Sender Settings, the range of values is from 290 Volts DC to 310 Volts DC. This initially struck me as interesting, but odd. The upper scale of the 52-Set meter is from 0 to 300 Volts DC only. I then noticed the voltage range for HT1 stated on the Table in Page 127 was 0 to 600 Volts DC. If this information was correct, then when reading Sender HT1 values on the 52-Set Meter, the indicated values on the meter would have to have a ‘x 2 Factor’ applied to them, and the metering circuits would have to be set up accordingly.

When running a no load test of the Sender (no valves present), my HT1 reading was a solid, steady 150 Volts DC. Apply a ‘x 2 Factor’ and I get a perfect 300 Volts DC, which I was quite pleased with. I ran this information by Jacques Fortin and he checked the documentation and circuit diagrams. Sure enough, he found no evidence either of this metering design being mentioned in the manuals, and did confirm when the Receiver Meter Switch is on SENDER and the Sender Meter Switch on HT1, a pair of 600K resisters are brought into the circuit in series giving it a 600 Volt rating as per the Sender Voltages Table in the Operators Manual.

I am now going to start reinstalling the valves back into the Sender one at a time, starting at the front end of the block diagram. With all of them in place originally, one of the operational Tests for the Supply Unit had the two dynamotors running with 300 Volts HT1 just nicely, the next test up, however, had a massive load hit the dynamotors on startup and the indicator lamps nearly went out. And the HT1 reading was an alarming 180 Volts DC.

More as the saga unfolds.


David

[David Dunlop]

I pulled the Sender back out of the Carriers No. 4 this morning to install V6A, the Voltage Regulator and see what happens with the Sender when everything is powered back up.

Getting the Sender back into the Carriers No. 4 has always been a challenge, ever since it arrived. It wants to hang up at the last half-inch or so and ends up having to be pressed home in the upper left corner, and then wiggled some more to get the upper mounting bolts installed.

As I was swinging the Sender up onto my work desk and turning it around to install the V6A Valve, something caught my eye for the very first time with the PL2A 8-pt Connector mounted in the upper left rear corner of the Sender chassis. The MIC Terminal in the lower right corner of PL2A was bent upwards. So much so, in fact, that the corresponding Spade Terminal for this connection on the Carriers Plug was sliding underneath the MIC Terminal and pushing it upwards to the point where a crack had developed in the Bakelite body of the Connector, between the MIC and FAN Terminals. This is what has been causing the poor fit of the Sender in the Carriers No. 4, and who knows for how long.

The three photos today show the extent of the upward shift of the FAN Terminal and the crack to the left of it.

Now I just need to figure out the best cure for this problem, which will also successfully cancel any future travel plans for the crack that has developed. It does not look like it has caused any significant damage to this point in time.

I think I have said it before, but there is never a dull moment with this project.


David

[David Dunlop]

After studying the damage caused to the MIC Terminal of the PL2A Connector for a while, I decided a full disassembly of the connector was not necessary and that the terminal itself could be repositioned correctly with a little patient TLC. The trick would be not to try and fix everything at once by just trying to bend the entire terminal back down to where it should be located.

I started by inserting a medium sized slotted screwdriver head into the gap in the terminal and locking the blade up against the base of the terminal, directly below the round head slotted screw. Then I gently bounced the lower terminal blade a number of times until it was lined up with the others in the lower row of the connector. This left an excessively wide gap in the terminal, which then needed to be closed up by getting the upper terminal blade lowered somehow.

I found a combination of pinching the terminals together with my fingers and alternating with a pair of adjustable pliers worked well. After a few such pinches, I would have to stop and repeat the screwdriver move on the lower blade of the terminal to keep it back where it should be, but after about 20 minutes work of alternating the pinching and lower blade adjustment, I had the MIC Terminal looking just like a couple of the other terminals on the connector with wider gaps.

The proof was in trying to reinsert the Sender back in the Carriers No. 4 and this time it went a lot more smoothly than it ever has before. Getting it installed is now comparable to installing the Receiver and the Supply Unit, so one more unexpected item has now been fixed with this 52-Set.

In the attached photo, you can see how much better the MIC Terminal lines up with the other in the PL2A 8-pt Connector.



David

[David Dunlop]

The fact there are so many pieces to this project can be very daunting at times, but every once in a while this proves to be a blessing.

I have been spending the last few weeks focused on sorting out the Sender electrically. A strong part of this motivation is the simple fact I do not have a back up Sender assembly I can turn to if anything serious fails in the one I have on hand. Should that happen, I have a vey large paperweight sitting on my bench.

The second, related motivation is the fact I experienced a massive load hitting the Supply Unit when I first applied it in full power mode to the Sender, suggesting something was indeed seriously wrong somewhere, and that it was very likely in the Sender.

In the process of considering likely candidates for a problem in the Sender, I was looking closely at a couple of transformers as possible candidates this week and going through the Parts Lists to glean any useful information held therein. While doing so, I thumbed passed the two Rotary Transformers when a detail regarding the MG1A unit struck me. Its input rating was 12 Volts DC at 7.5 Amps. That prompted me to check its big brother MG2A directly below it. Its input rating was 12 Volts DC at 25 Amps. I was actually quite shocked, no pun intended.

I then checked TABLE VII, CURRENT DRAINS on Page 20 of the Operators Manual and there it was, 31 to 35 Amps in Low to Medium Power when the Sender was active in the Set. I had completely missed that point in getting overly concerned about potential problems with the Sender itself. I am currently running the 52-Set on just one CPP-2 Power Supply with a maximum output of 12 Volts DC and 22 Amps.

I am not that impressed with myself this morning, but still glad I discovered this when I did. Now to get the 2nd CPP-2 Power Supply I purchased from Brian Asbury last year paralleled into the system today and try again.


David