Wireless Set No. 52 Canadian - Project

[David Dunlop]

The mid-level shelf plays into this saga at this point so I thought I would start there with a photo of the three components mounted to it. While taking this photo, I noticed through the lens, the trace of part numbers along the face of the shelf, directly below the middle and rear components. A check of the photos Jerry Proctor posted of the 52-Set Supply Unit on his website confirmed these numbers should have been there, along with similar numbers stamped onto the side of the front component and the one directly above the middle one. Large black Roman Font with a heavy overcoat of varnish. All these had been very carefully cleaned away. Why, I wonder.

From left to right, these three components on the shelf are:

L28A, the AF Choke (Smoothing Filter) for the MG1A LP Rotary Transformer.

L26A, the RF Choke (Smoothing Filter) for the MG1A LP Rotary Transformer.

S11A, the Dynamotor Input On/Off Switch relay again.

The second photo goes back to the underside and the shelf again and the visible hardware. Note the small BA screw securing the L26A RF Choke above it. This screw, and two others in the entire Supply Unit, are the only ones I can find that still retain their factory original internal toothed Shakeproof washers. Virtually every other Shakeproof washer has been replaced with much larger thickness external toothed washers. I checked both editions of the Parts Listings for the 52-Set and these heavy-duty external toothed washers are not listed at all. They do not show up in any of the other 52-Set components either.

One might think that is no big concern, but take a look at the third photo today. I have slid the Cases, Metal C1 for the Receiver Vibrator Supply back onto its tray in the Supply unit, carefully levelled it and slid it in as far as it can go. It hits the front left hex nut securing the large L28A AF Choke on the shelf above and stops dead! That external toothed lock washer is far too thick. If you look carefully at the hole in the hex nut, you can see the end of the machine screw is set back in the threads of the hex nut. It is not flush with the face of the nut. In fact, the setback is suspiciously similar in depth as the amount of space needed for the Cases to clear the hardware completely. The only way you can get the Cases to go all the way down its tray is to apply a lot of downward force on it to flex the front section of the tray down far enough to get the leading upper edge of the Cases under the hex nut. As soon as you release that downward force, the Cases is stuck and the only way to get it all the way into the Supply Unit is to block the front of it with a piece of wood and pound it home with a mallet. Remember the big long gouge along the top of the Cases in the last photo of Post #765?

I know that the upgrade kits for the two Rotary Transformers in 1945 included new sections of wiring harness. This new harness was all done in solid colour plastic sheathed wire, as opposed to the factory original white cotton and trace style of harness. Most of the Supply Unit would have to have been disassembled to do all that replacement work and from the wiring part, it was done very well. The looms that had to be disassembled were all very neatly relaced when finished. You can see a mix of all original, all new and blended throughout the Supply Unit. What I do not understand is why they replaced all the Shakeproof washers that had a great international reputation for being very reliable electronics hardware, with these big, external toothed washers that did not fit properly, when all the original hardware was right there in front of them in the first place?!? Crazy!

Time for some Egg Nog!


David

[David Dunlop]

Here is the photo from Jerry Proctors website. It is actually the right hand side of a Supply Unit owned by Denis Chouinard.

David

[David Dunlop]

Well, it looks as if Philco Canada was not only involved with the headgear manufacturing with RCA Canada for the 52-Set, but they also had the contract to build the Vibrator Unit Power Transformer T7A (CMC 97703), ZA/CAN 4413.

Another few discoveries when I flipped the Vibrator Unit over and at first thought the interior had been horribly rusted somehow, and then realized it was actually copper plated.

Then the odd stuff showed up again.

A very careful look confirmed virtually all of the components and wiring are factory original, but every original Shakeproof washer had been removed and most replaced with those ugly, oversized external toothed washers. Some screws were even found to have had Shakeproof washers under them at one time but they were removed and replaced with nothing at all.

When you look at all the hex nut hardware, you find it was originally given a coat of varnish at the factory, but several hex nuts and open screw ends now have an additional overcoat of a thick yellow ‘paint’ that is probably some form of Loctite.

The last two photos in this Post highlight yet again the very sloppy, indifferent workmanship performed by whoever worked on this Supply Unit. The pan head screw at the very lower, right rear corner never properly meshed with both pieces of metal to pull them in together. I have experienced this phenomenon myself many times over the years. The screw threads into the first piece of metal just fine, but with not enough pressure applied to the face of the first piece of metal as the screw tried to grab the second piece, the screw just spins against the second piece but continues to thread into the first, pushing the two pieces apart. Usually you can back the screw out and apply correct pressure and try again with success. Sometimes you might have to back other screws off a bit to allow for better alignment of the two pieces of metal for the last screw. The point is, it is easily fixable. Clearly, nobody bothered here, slopped some yellow goop on the end of the screw and walked away. Adding confirmation to the indifference, about halfway forward on the same side, a bulkhead plate is mounted across the width of the assembly using the same pan head screws. As noted in the last photo, the same problem occurred with the same indifferent response. What you cannot see here because it is out of camera range is the second, upper screw showing the same effects.

So a Supply Unit component that required no component upgrades at all, was torn apart to have perfectly good hardware replaced by the wrong hardware as part of an assigned task somebody clearly did not want to do. Could have been worse I suppose, but one more reason to track down a good supply of Shakeproof washers.


David

[James D Teel II]

That sounds like it might have been a school house unit; one that was taken apart and repeatedly put back together. My own army is known for things like that.

[David Dunlop]

It certainly has that look about it, James, though I don’t think 202 Workshop was a training facility, beyond the possible monitoring of recent Trade School Graduates til they came up to speed.

I think most Canadian Military Trade Training takes place at CFB Borden, north of Toronto. Anything new arriving into Military Service that needed maintenance/servicing, would likely see examples of the equipment going to Borden early in the acquisition process so the various schools could gear up appropriate training courses. However, there are others here on MLU better qualified than I am who might be able to confirm if Wireless Maintenance was taught at Borden and if so, if they maintained a supply of the various sets up there for training purposes.

David

[David Dunlop]

I have been looking closely at the Supply Unit lately, a bit nervously at first, but the more I study it, the better idea I have for developing a logical game plan in place for restoring it. The biggest part of that plan is going to be getting all the parts and things required on hand and ready to go before I start.

The Supply Unit will have to be fully disassembled in order to get everything done. So far, that process appears to only involve unsoldering one electrical connection, to the Blower Motor mounted to the front panel. I think (subject to further study) all other soldered connections can remain intact, provided I sort out the best sequence for unbolting all the other components for removal. The most challenging bit I can see so far is the removal of the front panel. It will be captive on the two drop cords until I can move it far enough away from the chassis of the Supply Unit to access the phenolic panel terminal board all the Drop Cord wires are screwed on to, directly behind the panel.

One of the things I have needed to sort out has been the types/sizes of Shakeproof Washers used in the Supply Unit, since as I already found, very few original internal toothed washers survived the 1966 Overhaul at 202 Workshop. This has been quite a challenge.

I started by listing the Shakeproof Washers from the Hardware List for the Wireless Set No. 52, taken from the 1945 Issue of the Master Parts List. This list of washers was only 10 items long and no data references were provided at all, just a 4-digit part code that could have been Canadian Army, or Shakeproof in origin. To get more data to play with, I went to the Illustrated Parts List for the Wireless Set No. 19 Mk III Cdn and added all the Shakeproof Washers from it to my list. That gave me 20 washers overall to play with, along with their related VAOS Numbers.

The other valuable thing about the 19-Set Parts List is that it is stuffed full of exploded illustrations showing the exact relationships for all the parts, including the hardware. It took a few days, but I was able to search each diagram, find the Shakeproof Washer and link it to a specific type and size of screw, or hex nut either American Standard, or British Association. That gave me 17 bits of data for 40 possible machine screw sizes, with a grey area for shouldered screws when the washer was fitted to the shoulder and not the main shank of the screw.

For the 14 American Standard Size Gauges I could identify, it started to look like the last two digits of the Parts List Shakeproof Washer Numbers related to the Gauge Size of the Machine Screw. That led me to suspect the first two digits probably held additional useful information, but there were just too many options. So yesterday morning I decided to call in the experts at Shakeproof in Wisconsin, USA and ask if they could help. I have now received a reply back from the Shakeproof Sales Team that I was indeed on the right track.

Shakeproof did have a ‘smart number part number system’. It is geared towards the American Standard Size Gauge and the last two digits of the part number for the washers identify the machine screw size up to #12. At ‘14’ it switches to standard inch fractions, more or less logically. More on that will follow shortly.

The first two numbers on the part numbers for the washers identify the tooth pattern and the material used in the washers.

I am currently updating the spreadsheet I have created to sort this all out and when completed will post a copy of it here for future reference, and include a discussion of how the BA Machine Screws fit in.


David

[David Dunlop]

A little tiny bit pf progress over the Xmas Holiday.

I was able to find a correct washer and hex nut for the 6-32 x 3/8" machine screw that fastens PL5A to the right rear end of the tray on which the Receiver Vibrator Supply Unit mounts, so that screw, as noted in Post #766 is now complete for reinstallation. I also found my set of Ignition Wrenches, of which the 5/16" one will be needed to do that work later on.

David