Wireless Set No. 52 Canadian - Project

[David Dunlop]

Two of the four 6V6G Valves in the Sender are shielded; V5B and V5C (the Driver Doubler and Driver respectively). They are visible right inside the Access Door with the two spring clip retainers secured against the tops of the two CANS with a wing nut.

The tops of both cans had accumulated water over the years, with V5C, closest to the front of the Sender being the worst. To get better cleaning access to the interior of the chassis, I pulled everything from the wing nut down to the CANS and decided to clean them up before reinstalling them. An interesting installation.

The wing nut was straight forward enough. The next down was a bit of a surprise; a small C-Clip. Popped it off and then the Spring Clamp for he CANS on V5C came off. Next a flat washer, followed by the Spring Clamp for CANS on V5B. At the bottom of the threaded post was the final flat washer.

It took a bit of cleaning but they now look aged, rather than totally neglected.

David

[David Dunlop]

I almost forgot this little bit of electronics history.

Back in Post #303 about the sole upgraded/replaced component in this Sender, I neglected to mention the odd looking yellow component tucked in below the capacitor. It looked like a resistor to me but the markings were nothing I had ever seen before.

I took a photo of it and sent it to Jacques Fortin for identification. I received his reply last evening in which he confirmed it was indeed a composite resister with a pre-WW2 Colour Code. In the Sender, it is R46B in the PA Circuit for V7A, the 813 Power Amp. The resistor provides the keying bias.

Armed with that information, I went looking for its partner in the Sender, R46A, located in the V5D (6V6G) Screen circuit, where its job is to provide voltage dropping. When I found it, it sported the more conventional coloured ring code. Both resistors are original installations, with no signs of replacement on either.

The earlier code used a full body colour on the resister to identify the first rating digit. A wide band at one end was the second digit and the ‘Multiplier’ was a third band or blob in the middle of the resister. The Gold, or Silver, tolerance rating (if applicable) was applied at the opposite end from that for the second digit.

This older resistor coding pretty much disappeared in the 1940’s, but when I checked my Amateur Radio Handbook from the mid-1960’s, a detailed explanation of this older coding system for resistors was still provided. The information was completely gone from the handbook for my Amateur Course a few years ago.

Jacques also sent me the attached photo of some of these old resistors he has on hand. Colourful little suckers,

David

[David Dunlop]

I was able to cut two small pieces of 2x4 to block up the two Indicators today. This takes the load of their weight of the couplings to the Condensers and stops them from wobbling around.

All removable pieces are now off the Sender front panel as well, with the exception of the remains of the small phenolic resin mounting board for the TERMINALS, Aerial at the top of the panel. I need to carefully drill off the crimps holding the rivets for this board in place to remove the rivets, I need to size and source replacements to put a new assembly back in place when the time comes.

David

[David Dunlop]

A little bit more chassis cleaning has been done. The current project was to get all the oily soot off the phenolic board directly behind the two COUNTERS, and the two COUNTERS themselves.

The board is now done and the left hand COUNTERS. I have about half of the right hand COUNTERS to complete. It nice to see that when the small windows on the two COUNTERS were cleaned, the numbers went from a dull yellow, back to their original bright white look. I was hoping, but not totally certain, that would happen. They look to be well-sealed units, but one never knows what time and hostile conditions can do to things.

I do find these COUNTERS are VERY jumpy, for lack of a better word. The slightest movement of the assembly starts the dials turning. It takes a bit of patience to get the right side assembly in its correct position for mounting to the front panel. At that point the dial comes nicely to all zeros. It is going to be a very careful reinstall when the time comes.

Because these COUNTERS are so sensitive to movements, I am thinking they must have been assembled and shipped from the manufacturer, with some sort of retaining clip, or block, fitted to prevent any dial movement until they were installed on the Sender, and said clip, or block, was only removed once the COUNTERS were properly in place.

David

[David Dunlop]

I spent a slow, and reasonably careful (more on that later) morning today, cleaning up most of the Sender chassis interior. The sequence of soapy water toothbrush scrub, gentle air gun towards strategically placed paper towels, mild cleaner scrub with toothbrush, rinse, and air gun, is tedious work, not to forget mention of careful drying with Q-tips and more air gun, but the end result is rather pleasing when done.

If you scroll back to the second photo in Post #207, you will see the before image. Oily carbon soot everywhere. Now the phenolic boards are all shiny brown. I can actually see the colour traces in the main wiring looms. The colour code rings on the vertical stack of large resistors can been clearly seen again and all that scary carbon deposit is finally gone from the two large ceramic terminal plates and the rest of the BAND Selector Switch assembly. I will wait until just before reassembly to clean all the switch and relay terminals with DeOxit.

A few more items in the chassis remain to be cleaned, but I am finally over that particular hump and the remainder needs a bit more careful study of how best to position the Sender chassis, while in a disassembled state, to get safest access to the parts that still need attention for cleaning.

David

[David Dunlop]

I mentioned in my last posting the cleaning process today on the Sender chassis was almost uneventful. Well here is what I discovered about the word ‘almost’ today.

Back in Post #280 and Post #281 I had discussed what I had learned up to that point in time about the COUNTERS Coupling Assemblies used in the COIL, Aerial Tuning and Senders PA LOADING Drives respectively. The assemblies used in the Sender are more sophisticated, utilizing a lower Bakelite plate with small pin, and an upper tapered metal plate with a slot the pin slid into. There was also a somewhat mysterious SPRINGS, Coupling Assemblies wrapped along the top surface of the tapered metal plate and snugged up against the pin from the lower assembly. It was clearly there to provide some tension to the assembly, thereby taking up any play, or slack in the coupling, but it seemed a bit to vulnerable to any excessive movement. My hunch, in all respects, was correct.

With the Sender now resting on its back on the worktable and the bottom towards me, I now needed to access the top of the Sender chassis for cleaning. A simple enough thing to achieve I thought. Just carefully lift the Sender, turn it 180 degrees, and lower it back down with the top now towards me. The detail I forgot in all this was I had removed the two small wooden blocks from under the two COUNTERS assemblies to gain access to the phenolic board behind them for cleaning. As I lifted the Sender up from the supporting 2 x 4s on the worktable and started to turn it, I saw the right hand COUNTERS assembly dip down and swing suddenly. That was alarming enough, but at the same time I heard a very heart stopping ‘TWANG! Tinka-tinka-tinka-tink’, and then silence. By now, the right hand COUNTERS was actually touching the Bakelite below it and the two parts of its Coupling Assembly were clearly no longer aligned with each other. I carefully set the Sender on the carpet and looked for small SPRINGS, Coupling Assemblies that was no longer in place. It was not in the chassis. A first look at the top of the worktable showed nothing, but when I moved the two 2 x 4s, there it was, resting up against the edge of one of them.

The good part of this event was I discovered once the SPRINGS, Coupling Assemblies is removed from the system, the COUNTERS assembly with the attached upper metal coupling plate can be lifted free from the lower plate. That provided a great cleaning opportunity, once my heart rate had returned to normal. I knew this particular LOADING Coil was snugged back to its zero point, so all I had to do was turn the COUNTERS back to all zeros and remount is aligned to its lower plate and replace the SPRINGS. That newfound knowledge means the other COUNTERS will be able to be reset to Zero far more easily than I have thought, when the time comes.

I added a photo of the top plate of one of the COUPLING Assemblies showing the end with the pin sticking through and the SPRINGS against the side of it.

I am sure this will not be the only heart stopping moment in the restoration journey of this 52-Set, but as long and none of the others involve high voltage/amperage, I will be a happy man!


David

[David Dunlop]

I got another bit of cleaning in the Sender chassis done this morning, deep in the lower back section and was able to bring the Sender Tuning Selector Switch back from beneath its cover of oily soot. I was amazed to find the Switch Plate was marked with luminous green paint. I would have thought it was far too dark in that location for such paint to work, unless there is enough glow from the surrounding valve filaments to keep the paint active.

David