Wireless Set No. 52 Canadian - Project

[David Dunlop]

Here are the 10 Resistors in the V1J and V5D Circuits I have been looking into. The data is in order of Circuit Reference, Rating, Tolerance, Circuit and Test Result.

R12A, 250-1/2, 20, T2A Primary Feedback Voltage Div, Tested 8 Ohms *
R16A, 400-1, 20, V5D Cathode Bias, Tested 560 Ohms *
R27D, 5,000-1/4, 20, V1J Cathode Bias, Tested 5,480 Ohms *
R31D, 10,000-1/4, 20, T3A Tertiary Feedback Voltage Div, Tested 8 Ohms *
R37A, 10,000-20, 20, V5A Screen Voltage Dropping, Tested 10,000 Ohms
R41B, 20,000-1/2, 20, V1J Plate Decoupling, Tested 23,070 Ohms *
R46A, 40,000-1, 15, V5D Screen Voltage Dropping, Tested 40,000 Ohms
R49A, 100,000-1/2, 20, V1J Plate Load, Tested 126,400 Ohms *
R56E, 500,000-1/4, 15, V1J Screen Decoupling, Tested 590,000 Ohms *
R61A, 1 Meg-1/4, 20, V5D Grid Leak, Tested 1.178 Meg Ohms *


* To be sourced for replacement.

And the Saga continues.


David

[David Dunlop]

I sent a copy of my testing results to Jacques Fortin the other day and he provided me with some very useful feedback.

First, he pointed out I had missed a couple of resistors in the V1J and V5D circuits I was looking at (R29B and R47C). I am on the hunt for them now and will report back on what I find.

The second issue he brought to my attention was regarding the results for R12A and R31D. Both of these resistors were quite different from one another but both tested 8 Ohms. I thought that was odd at the time…end of story. However, Jacques brought to my attention something I had missed in the Circuit Diagrams.

These two resistors are both serving as Feedback Voltage Dividers: R12A on the Primary of Transformer T2A and R31D on the Tertiary of Transformer T3A. As such, they are wired in parallel in these two circuits, so it is not possible to get an isolated Ohms reading from them just by putting your VTVM probes either side of the resistor body. In doing so, the meter reading is biased by the transformer. You need to disconnect one end of the resistor from the circuit involved to get a pure reading of the resistor. Both of these resistors are a bear to get at, so I have decided I will simply replace both resistors outright. Do tricky work once and be done.

The other really nice bit of information from Jacques, was that he took the time to document the best current resistor equivalents that I could use to replace each of these older components. This was something unexpected, but invaluable for me. I simply do not do enough regular electronics work to be comfortable substituting modern resistors for older ones. Bumping up the wattage rating to get a resistor of correct Ohms is one thing and I have done that just fine in the past with 1/4-watt resistors. Modern ones look way too small in a piece of vintage electronics and the leads are always far too short to cover the distance between Panel Tags in a 52-Set in any event. But I am just not comfortable going to higher Ohms ratings for any given circuit. I worry too much I am going to buggar things somewhere down circuit.

Other than that, so far so good.


David

[David Dunlop]

I was able to find the two remaining resistors Jacques had mentioned to me, fairly easily. I must be getting used to tracing the components finally.

R39B is located on the rear end of the Sender Tag Panel AS, which is located on the inner right skirt of the sender chassis. R47C sits right at the end of the Microphone Jack assembly. Photos attached. The test results for both are as follows, following the same convention as my earlier posting for the first 10 resistors:



R37B, 15,000-2, 20, V5D Plate feedback Limiter, Tested 15,960 Ohms
R47C, 50,000-1/4, 20, V1J Grid Voltage Dropping, Tested 58,200 Ohms


Both of these will be replaced.


While I think of it, Sender Tag Panel AS, in the Illustrated Parts List for the 52-Set is actually, PANELS, Phenolic, 12-Tag ZA/CAN 4224.


David

[David Dunlop]

I now have a list of current suitable carbon composite resistors to replace the ones I have found so far needing such attention in the Sender. Finding ones I can actually use in restoring the Sender is shaping up to be a very big challenge, and the fact it jogs me back to the same issue I had when replacing resistors in the two receivers is not helping.

Working on any of the smaller Tag Strips, or the valve sockets, is not a problem. Even the smaller Tag Panels can be worked with, but it is the larger Tag Panels which are a problem. The tag spacings on these panels are either 2.25 inch for the smaller ones or 2.5 inch for the larger ones. When you start looking at replacement, new production, carbon composite resistors, you quickly find the sum of the lengths of the resistor bodies and the two axial leads seems to give a modern standard length of 2.38 inches. So with a lot of careful dicking about with an easily accessible Tag Panel, you can just fit a new resistor across the smaller panel, but are SOL doing so with the larger Tag Panel. Most of the resistors currently needing attention are, of course, on a large Tag Panel. I am a bit of a way from getting the capacitors sorted, but suspect I am going to run up against the very same 2.38 inch overall length limit with them.

There are a few companies out there dealing with fairly extensive NOS supplies of carbon composite resistors but none (rightly so) guarantee the specs of the components anymore, and using them for jewellery purposes seems a common theme.

About half of the resistors I am looking for are also used in the receiver so I could hunt them down for testing and reuse, but if they are not installed in Tag Panels currently, it is very likely their leads have been trimmed too short to be of use, even if solidly on specifications.

So the Sender sits on the bench while I ponder the situation.



David

[David Dunlop]

It is interesting how simple little things can bring a big project to a halt.

The valves from the Sender are all neatly packed away on a corner of my work bench and the Sender sits quietly covered up to one side, while I try and sort out finding replacement Carbon Composite Resistors that I can actually work with in the 52-Set restoration.

The problem is with the modern overall length of new resistors (lead, body, lead). Turns out wartime manufactured resistors of this type had an overall length of about 3.4-Inches. With the two main sizes of Tag Panels used in the 52-Set having tag spacings of 2.25-Inches and 2.50-Inches, this component length was ideal. What I have been finding in the modern market are most overall lengths coming in at 2.38-Inches, so you can quickly see the road block.

On the bright side, some international inquiries have resulted in leads trickling in (yes, there is a pun there) of a few suppliers about with Carbon Composite new made resistors with overall lengths close to 3.0-Inches. I may have to go to higher wattage ratings than the original resistors to get ones that will fit, but that will not affect performance at all. It is just all very time consuming.

And there is yet another wrinkle in the T-shirt. To replace all the resistors currently identified as needing it, two of the Tag Panels must be removed from the sides of the Sender chassis to better expose the tags for working on and these panels hold nearly 10 capacitors that need to be tested. I cannot reach the back terminals on any of them for testing at the moment and I know a few of them will be toast. Adding to the excitement, a few of the capacitors will have to be removed to expose resistors tucked behind them that need replacing. So a whole bunch of adventures are currently hurtling down the side roads towards the main highway and I still have not finished reading the road map!

There is an interesting curious side to all this, however.

Since I had carefully disassembled the spare Receiver I had on hand, I decided to check if any of the resistors I needed to replace in the Sender, might also have been used in the Receiver and test them for possible use. There were a few, but all were installed in locations where, if carefully removed, their leads would have been far too short for reuse in the Sender in any event. But something interesting in the way the Canadian Marconi Company arranged the parts lists in the Working Instructions Manual for the 52-Set unexpectedly popped up when you looked at long lists of the same component.

It is common practice for companies to list specific parts in ascending order of their electronic specifications. For example with resistors start with 1/4-Watt and within that group list from lowest Ohms value to highest. Then go to 1/2-Watt and repeat. And so on. Same process for capacitors. CMC took this organization one step further. They have a column in the parts lists that identifies which component the parts are used in and I discovered when looking at the larger lists of identical parts, CMC always listed the components in the following sequence of first to last:

R: Receiver
CC: Crystal Calibrator
S: Sender
SU: Supply Unit

So if you look at capacitors in the C3- series ( .1 uf, 500 Volts, 20%), there is a lot of them. C3A to C3Z are all found in the Receiver. C3AA to C3AF are found in the Sender and C3AG to C3AK are in the Supply Unit.

At the other end of the spectrum, C32A ( .01uf, 500 Volts, 20%) is in the Sender and C32B in the Supply Unit…end of list for item.

I do not know why CMC adopted this convention in the parts list found in the 52-Set Working Instructions, or even if they did it in other products as well, but at least I now am aware that any future components in the Sender I find with a Circuit Reference Number ending in ‘A’ will definitely not have a spare lurking in the Receiver or Crystal Calibrator.


David

[David Dunlop]

One of the nice things about a project this size is that there is always things you can accomplish when work stalls somewhere else.

That is the current case with the component replacement work I ws doing with the Sender. It is going to take a while to source all the required resistors and capacitors I need to hopefully solve the majority of issues around valves V1J and V5D and all the bits need to be replaced at the same time. So I have returned all the valves to the Sender and the Sender to the Carriers No. 4 until such time as I have all the needed resistors and capacitors on hand.

There is a trick to getting the three main components back into the Carriers No. 4 easily. If you do not keep the chassis you are putting back completely square to all side of the Carriers No. 4 as the sockets on the chassis engage the plugs at the back of the Carriers No. 4, they will bind up and it is a royal pain in the butt to get them apart. The Sender slid in so smoothly this time, I almost thought something had gone horribly wrong.

So the part of the project I moved over to was a little painting detail on the hammer that is part of the tool kit for the Wireless Set No. 52. The original hammer was a ‘BULLDOG’ product, from what I can make out on the decal in the first photo today. A pair of tool companies show up in researching this name, one in England and the other in the United States. A few old photos of corporate logos show up, but none so far of that elongated diamond decal in the illustration. The hammer I found for the tool kit is not made by Bulldog and the handle length is about one inch shorter than the original tool specifications, but on the plus side, the handle is the correct shape, clear varnished hickory and the head is the correct weight and style; the second attached photo. I had no idea there were so many different styles of ballpane hammer heads until this project arrived in my lap.

I may never find a good condition original hammer for this project, so decided to replicate the look of an original with what I have on hand. The most obvious feature is the black end on the handle, but the top end of that feature has a distinctive angle to it. Practice as I could, I was not able to get that good a look with any kind of tape rapped around the handle. You are trying to keep a straight line around an oval cross section that is narrower at the top than the bottom of the angle. After months of ruminating over this, I finally had my ‘Eureka Moment’. If the end of the handle was dipped into paint at the correct angle, to the correct point on the handle, mission accomplished. But how does one keep the handle perfectly steady? A few days of thinking about that …and then I realized, you fix the handle and move the paint can.

I did have a one quart can of gloss black enamel on hand that would work, so that was a start. The next step was to get reference points onto the front and back faces of the handle to pinpoint the two ends of the upper angled paint line. I was able to scale these two measurements off the illustration and proportion them, with some basic High School Math, to the shorter handle I was working with and transferred these two reference points to my handle; the third and fourth pictures.

So far, so good.


David

[David Dunlop]

The next step was sorting out fixing the hammer I had in a stable correct position to work on. My portable bench vise came in handy here. The first step was to fit a small strip of oil board over each jaw of the vise to avoid marking up the head of the hammer. I then fit the hammer into the vise just firmly enough I could still move it back and forth in the jaws. Also checked to ensure the handle was dead vertical to the floor.

I could then set the vise close enough to the edge of the bench the hammer sat freely out of the way. With the help of a spirit level, I was able to adjust the hammer handle until the two reference marks were dead horizontal. Photos 1 and 2 here.

With the paint mixed, off came the lid and a quick check confirmed the level of the paint was low enough that it would not spill out as the hammer handle displaced the paint when immersed in it. Since the paint was a liquid and seeks its own level, I really only needed to reach the top of the reference mark on the back of the handle to get it right, but I had to raise the paint can slowly enough to allow the meniscus to just come up the the required point and then lower the can back down.

There were a couple of points to consider now. Most important was the handle is at an angle now and all the excess paint is actually draining towards the front and bottom corner of the handle. That is OK for a short while as that means the excess paint is draining away evenly from the angled line you have just created, and you want that initially.

I held the paint can under the handle until the steady flow of paint ceased and the subsequent drops became infrequent and made sure a pile of rags was on the floor directly under the handle. At this point, the paint is still going to flow down the handle slowly, but you now want this to flow evenly around the entire handle so the thickness of the final paint layer is even around the entire handle. That means slowly moving the hammer handle back to a vertical position; the 3rd photo. At this point, I used paper towel to draw off excess paint from the very bottom of the handle, several times over the next hour, to reduce a ridge accumulation of paint around the bottom rim of the handle as much as possible.

24 hours later, the paint was dry and I was able to remove the hammer from the vise. I am quite pleased with the result in the last photo. A bit glossier than the varnished areas, but a little careful rubbing down after the paint has hard cured in a couple of weeks, will solve that problem.

If I ever do find an example of the original BULLDOG diamond decal to work with, I am also going to have to add a small black paint and metal stamped ‘R’ to the side of the handle to clearly ID it as a replica.It is what it is, not what somebody might want it to be after I am all dust and ashes.


David

[David Dunlop]

Finally caught up on another little task this morning; getting the stencils back onto the Reels, Cable No. 2 Mk II for the 52-Set.

These reels are identical to the standard, similar reels of this type issued by both the Canadian and British Armies, but like a number of the items Canadian Marconi Company issued with the various 52-Set Kits, they ordered a number of reels directly from a manufacturer, and a CMC Part Number was added into the stencils for these items.

Since the stencils applied to the similar, but more robust reels used with the Aerial 4-Section that came with the 52-Set, were sprayed in a fairly light coat of flat white paint, I decided to go with the same process for this cable reel.

The first step was to trim down the two stencils I had made last year, so they would fit properly on either side of the hub assembly on the free end of the reel, as per the reel used with the horizontal aerial. Once the two stencils were properly trimmed and taped down, I masked off all the exposed areas on the reel with newsprint and applied several light coats of flat white spray paint from a height of about 18 to 20 inches and let the paint more or less float down onto the reel, to minimize any excess spray getting driven under the oil board. It took a few careful passes from several different directions to get a paint density comparable to the original markings on the aerial reel, and 20 minutes later, I was able to remove the stencils and found no trace of overspray anywhere.

Nice to have one more part of the project out of the way.


David

[Chris Suslowicz]

Originally Posted by David Dunlop

Finally caught up on another little task this morning; getting the stencils back onto the Reels, Cable No. 2 Mk II for the 52-Set.

These reels are identical to the standard, similar reels of this type issued by both the Canadian and British Armies, but like a number of the items Canadian Marconi Company issued with the various 52-Set Kits, they ordered a number of reels directly from a manufacturer, and a CMC Part Number was added into the stencils for these items.

Since the stencils applied to the similar, but more robust reels used with the Aerial 4-Section that came with the 52-Set...

Ha. Haha.. Hahahahaha...

I bought some "Reels, Cable, No.2" off eBay, and discovered when they arrived why the MoD had surplussed them.

The idiot manufacturer had mis-read the drawings, and cut the reel cheeks from steel plate of the maximum thickness on the drawing (which I think was supposed to be a pressed-in stiffening rib, though it may have been the soldered-on reinforcement of the reel edging that protected the user from the sharp edge of the tinplate cheek. Either way, each reel weighed several pounds - rather more than the correct design with the full quantity of wire on it.

Thankfully the original waist-mounted cable layer was long obsolete or the unfortunate user would have had difficulty walking in a straight line.

I think I still have one somewhere.

Chris.

[David Dunlop]

Wheels for a railway in your back garden, Chris?


David

[David Dunlop]

I thought a Progress Report on the 52-Set Project would be useful at this point in time. Work is still progressing, but in an ‘educational’ direction for a while.

I have never been one to start something without a plan, as much research ahead of time as possible, and a supply of the necessary parts needed for the work at hand to see it through to completion. It has always seemed more effective to disassemble something once, do whatever is needed to bring it back to good working order and then reassemble it

The work needed on the Sender has gone as far as I can take it at the moment, until I can sort out sourcing all the proper, available components efficiently, to fix what has been found needs attention in one go around. It would drive me nuts if the Sender was sitting in pieces for weeks on end while I bounced from pillar to post getting things done. I know the majority of passive and low voltage circuits in the Sender are in good working order and it is in the HT1 and HT2 circuits where items still need to be addressed.

In order to keep things going with the project at this point, I need to redirect my attention back to the Supply Unit once more. It still has a number of physical issues that need to be fixed/attended to, along with a couple of electrical mysteries related to the Receiver Vibrator Supply section. The Supply Unit, is a very compact design that even the Canadian Marconi Company admitted to in its documentation for the set. Repacking the dynamotor bearings and inspecting the brushes can be done with a minimum of careful disassembly, but is so much easier if they are both free standing on the work bench. To replace the dead Drop Cord, however, the front panel needs to be removed, and to remove the dynamotors, the case surrounding the Receiver Vibrator Supply must be removable from the Supply Unit Chassis, to gain access to the right side mounting bolts of the two dynamotors. That latter issue was what prompted me to focus on the stuck Receiver Vibrator Supply Case last year and get it to work properly. As you may recall, part of that work required removal of the Blower Motor assembly to access all the RVS Case hardware and I took that opportunity to clean and restore the blower components so that all Supply Unit parts that should still be in factory original Gloss Navy Grey, are now in that condition and done.

At this point in time, the only thing stopping work from proceeding on the Supply Unit is the need for correct luminous green decals to put onto the front panel when all other work on the Supply Unit has been completed, prior to final reassembly. As noted upon initial examination of the Supply Unit when it first arrived, the current decals were a 1960’s era remake item using yellow luminous paint, and too small a font. Why the Government at that time went with the most expensive, hard to find colour of luminous paint, instead of the cheaper, more common green, I do not know, but they did. The workmanship of applying the decals was beyond poor and subsequent damage to a number of them means overall, they have to be replaced.

I have now sorted out the steps required to replicate the correct looking decals for the Supply Unit. Making the water transfer decal sheets is now the challenge. Fortunately, the Operators Manual for the 52-Set contains a full front photo of the original decals for both the Supply Unit and the Coil, Aerial Tuning front panel. The challenge is that both are less than one half the required ‘full size’ image needed to work with for replicating, and this is where it gets tricky. Old printed photographs are composed of a mass of small, grey scale dots, which produce the black and white image you see on the paper. If you are not careful when trying to enlarge/blow up these printed photographs, you end up enlarging the dots to the point they become visible and the image breaks down. If you make a digital photograph of the original print image and try enlarging it, you risk the digital image breaking down into its component pixels and once again, the image breaks down.

I am not sure when it came into being, but there is now an area of digital image media known as Vector Graphics. With it, you can convert a digital photograph into a vector graphics format, which completely eliminates any breakdown of the image when it is enlarged. You can take a photograph of a postage stamp and turn it into a 20 x 40 meter wall mural, if you wish.

So last year, when we finally upgraded our 16 year old iMac to a new one, I also bought a vector graphics program and installed it, with this part of the 52-Set Project in mind. It is now time to learn everything I can about vector graphics and working with it. Not sure how long it will take, but I am actually looking forward to learning something new for the project. It will mean, in all likelihood, a reduction in things to post about on this thread for a while. In any event, we shall see what happens.

David

[David Dunlop]

Since I will not be operating the Sender for a while. I disconnected the 2nd CCP-2 Power Supply from my 12 Volt DC feed system for the wireless bench to tidy up the cable clutter in one corner. I took this opportunity to clean up the twin connector cable I obtained from Brian Asbury for this CPP-2 and the effort paid off, as it now looks much more like its probable ancestor, the Connectors, Twin, No. C1 which was part of the Remote Receiver Kit for the 52-Set. Before and after pictures attached.

While I think of it, the cotton twine on this cable in the before photo has a distinct waxy feel to it. I have noticed this before with most wartime cotton twines used to secure items for packing and shipping, and a few postwar military items as well. It is probably a bees wax based item and may even include fungicides. Anyone know if this would be the case?


David

[David Dunlop]

Since Starting this project, I have been curious about what company the Canadian Marconi Company subcontracted for production of the wireless tent kit they designed for the 52-Set.

The Parts list illustrations gave a very good description of the dimensions for the Wireless tent and its Valise. The tent itself was a slightly expanded version footprint of the then current 2-Man Officers Tent, with a correspondingly longer 2-Section Ridge Pole and pair of End poles. The valise was also slightly enlarged to accommodate thee larger tent components. The original Officers Tent Valise was never identified as such as it was unique to that tent. With the arrival of a slightly larger tent for the 52-Set to work from, the ‘TENT, WIRELESS VALISE’ identification was added to this valise, to avoid confusion in the field, in all likelihood.

To see if the manufacturer of the wireless tent could be identified, I posted the illustration of the valise on the MLU Forum recently and within 24 hours, Colin Alford had responded with some photos of a standard tent valise in his possession, with matching logo, name and date, S.S. Holden Ltd. of Ottawa. The original illustration, and Colin’s two photos are attached here, for your reference. It has only taken 80 years, but once again we now know one more subcontractor used by the Canadian Marconi Company during their production of the Wireless Set No. 52 Cdn.


David

[David Dunlop]

I was looking over my Carriers No. 4 a little while ago, primarily to refresh my memory about what work needs to be done to restore it. The actual restoration work breaks down into initial disassembly of all the little loose bits and separating the upper Box assembly from its lower Cradle assembly, when the time comes to work on it. Locate a few missing parts. Then straighten a handful of bent parts on the right hand side, strip off all the old NATO Green paint and then repaint it in as close as possible to the factory original No. 2 Brown paint. Let it all cure and then reassemble.

As far as missing parts went, the only ones I noticed I needed were all part of the Ground Terminals system located on the lower right side of the Carriers No. 4, where a pair of heavy duty wire braid grounding straps are used to maintain electrical continuity between the upper Box assembly and the lower Cradle assembly, across the insulation/isolation point of the rubber Bridges acting as shock absorbers for the 52-Set. The problem I have is the entire front Ground Terminal assembly is missing on my Carriers No. 4 and the rear assembly is badly bent and appears to be missing its wing nut.

The photographs in the 52-Set Manual suggested there definitely was a wing nut on the rear Ground Terminal, but the front assembly looked shorter in length overall and did not have a wing nut. Not helping was an illustration on Page 53 of the Operators Manual showing a wing nut arrangement on both Ground Terminals, but only the rear terminal actually in use. I got in touch with the owners of known surviving 52-Sets to ask how their sets were configured. All came back confirming just the rear assembly serves as the Ground Terminal, using a longer machine screw fitted with a wing nut and retainer D-Ring. The front assembly is merely a second connection between the upper Box and lower Cradle assemblies, using a shorter machine screw and hex nuts. No wing nut or D-Ring.

So with the help of other owners, I now know the rear Ground Terminal is a 1-1/4 inch long, 1/4 x 20 machine screw equipped with a wing nut and drilled near the end for fitting a D-ring retainer, to avoid loss of the wing nut. The front Ground Terminal is just a 3/4-inch long, 1/4 x 20 machine screw, both ground straps are 5.25 inches long by .75 inches wide heavy duty wire braid.

However, an unexpected discovery turned up in the process.

It seems the Engineers working on the design of the 52-Set at Canadian Marconi Company were quite concerned about the ground continuity for the set when in its Carriers No. 4. So much so, that where the holes are located fore and aft on the lower right side of the Cradle assembly, to which the bottom ends of the wire braid ground straps are secured, the Engineers designed in a large section of heavy duty copper plating against which the wire braid ends would be fitted.

Don Wright in Alberta brought these plated copper areas to my attention, because they have survived on his Carriers No. 4 finished in the factory No. 2 Brown, as per the attached photo. On the Cradle frame of my Carriers No. 4, the front Ground Terminal assembly was completely gone, but all I could see was a smooth NATO Green surface. Don assured me this plating should be there because it is quite thick and should even survive sandblasting, if done, when my Carriers No. 4 underwent its repaint to NATO Green.

Out came some fine emory paper and with just a few careful rubs, there it was, nicely outlined (second photo attached). Oddly enough, once I could see it, I could then feel it with my fingertip. At the front edge of the rectangle, where the NATO Green has worn and chipped over the years, I can now just make out the glow of copper down that line. I am going to pick away at this discovery with further careful sanding and a variety of cleaners to see just how much of this hidden bit of 52-Set design I can recover. Too hard to get at the rear Ground Terminal position at the moment, but it is now marked for a closer inspection when the time comes. The approximate size of this copper plated rectangle I have found is 3.0 inches long by 1.5 inches high.



David

[David Dunlop]

After some further careful fine sanding, scrubbing with a a small brass wire brush and several cleaners followed by a final wipe with acetone, my Carriers No. 4 has finally revealed its secret copper plating around the front Ground Terminal on the frame of the Cradle assembly.

The textured surface of the copper plate suggests this particular Carriers No. 4 underwent sand blasting prior to getting its postwar coat of NATO Green paint, so the odds of my recovering any of the factory original No. 2 Brown finish, have now been reduced significantly. But that is OK right now. I am just thrilled to have found this plating.

All of this prompted me to revisit the internet for more information on plating techniques and this particular process is apparently referred to as either ‘Selective Plating’, or ‘Brush Plating’. It is used for plating small, specific parts of larger objects that do not need full immersion tank plating, or for plating repairs. The same general principles apply as per tank plating. The recipient part is the ‘cathode’ connected to the negative side of a DC current. The ‘anode’ is still a piece of the particular metal that is to be the plating (copper, zinc, nickel, etc.) and it is connected to the positive side of the DC current, but the anode is actually inside an insulted tube, surrounded by an absorbent filling of fabric, filled with the appropriate electrolytic solution. The lower end of this tube is a wick allowing the solution to contact the cathode material being plated, thereby completing the electroplating circuit.

When I read all this, it jogged my memory of one of my uncles back in the 1950’s. He owned a 1956 Oldsmobile convertible, red and white. I cannot recall which model, but he got a scuff on the front bumper one summer and it was repaired by somebody who drove to his home and had all the kit in the back of a panel delivery truck. I watched him smooth down the scuff with some emory paper and then attach a ‘battery cable’ to one end of the bumper. He then pulled out a second cable with what looked like a small section of broom handle fitted to the end and start moving it back and forth over the scuff slowly for several minutes. And the scuff slowly disappeared. When this chap was finished, you could not tell the bumper had ever been scuffed and my uncle was very pleased.

So now I need to do some more internet reading to see if there are any DIY at home techniques documented for Selective, or Brush, Plating. This may be another handy skill to acquire.


David

[Bob Carriere]

https://www.ebay.com/itm/29566205094...sAAOSw9VpkSyzP

Looks like some one else has the WS 19 Bug........ love the homemade power supply. I have never seen one tested and on sale before.......

Bob C

[Bruce Parker (RIP)]

Originally Posted by Bob Carriere

https://www.ebay.com/itm/29566205094...sAAOSw9VpkSyzP

Looks like some one else has the WS 19 Bug........ love the homemade power supply. I have never seen one tested and on sale before.......

Bob C

Yet when I look at the pics I see all the old original paper components.

[Mike Kelly]

Originally Posted by Bruce Parker

Yet when I look at the pics I see all the old original paper components.

I noticed the same issue. Those old capacitors will not be reliable, they need to be replaced. I also don't like the exposed high voltage terminals on the power supply , over 500 Volts

The Wattmeter is not to be believed - it will be adding up and displaying all of the harmonic and spurious content of the transmitter, giving a false reading. The load impedance needs to be matched to the output impedance of the set otherwise there will be a false indication of the actual power output.

[David Dunlop]

Hi Bob.

I did see this one. Pretty nice looking Northern Electric from the outside and showing all the usual Mods with an interesting bit of service History, if the case is original to the set.

According to the Sellers description, all original caps and resistors were replaced, but the old ones were all left in situ and merely disconnected. I could see that working in Receive Mode but I am not sure i would trust modern, caps and resistors designed for solid state voltages with 80 year old valve driven equipment putting it into Transmit Mode for any length of time..

Lots of photos posted but I cannot see any modern caps of equivalent design to the original paper ones anywhere. Either they are all extremely well hidden, or perhaps small, button style were used and hidden under the originals.

Any interesting curiosity, but I would pass on it.


David

[Bob Carriere]

....had another closer look at the guts......and can't see where any modifications or parts replacement were done....... all the large paper condensers and not one "new" item added.......

Buyer beware!!!!!!

Bob C

[Bruce MacMillan]

having had a close look I can see many black Sprague TVA Atom series caps. These are fairly modern so I suspect some recapping has occurred.

[Chris Suslowicz]

Originally Posted by Mike Kelly

I noticed the same issue. Those old capacitors will not be reliable, they need to be replaced. I also don't like the exposed high voltage terminals on the power supply , over 500 Volts

The Wattmeter is not to be believed - it will be adding up and displaying all of the harmonic and spurious content of the transmitter, giving a false reading. The load impedance needs to be matched to the output impedance of the set otherwise there will be a false indication of the actual power output.

It's a very nice power supply, just missing the perspex/plexiglas sheet over the terminal strips and suitable DANGER - HIGH VOLTAGE labels.

As for the output power measurement, the EMERs specify a dummy load of (I think) 10 ohms and 30pF (plus a thermal ammeter) connected to the variometer output terminal in order to simulate an 8-foot whip aerial. Even that will include any harmonics, and you'd need modern test gear (spectrum analyser) to get any idea of the actual useful signal output - especially if using wire aerials or a different length of whip.

Chris. (I've got the "Dummy Aerial Set", but not the original Valve Voltmeter used with it (which is a little on the bulky side). Might try it with a later one at some point.)

[Mike Kelly]

This is a good article by Dave Lawrence. From what I have read about variometers, they are not ideal in a electrical sense , the rotary inductor or roller tuner is a better method of electrically adding length to the antenna.

https://www.qsl.net/ve3bdb/antmeas.html

These days, you can buy a nanoNVA device for hobby use. The VNA has the ability to analyze the complex impedance of the 19 set variometer and antenna and give a direct result in various forms. The nanoVNA are easy to buy on most of the popular retail platforms . And small spectrum analyzers are available for hobby use as well.

https://www.aliexpress.com/item/1005...d=gkAQdhUhNQmF

https://www.aliexpress.com/item/1005...170019037756_1

[Mike Kelly]

Originally Posted by Bruce MacMillan

having had a close look I can see many black Sprague TVA Atom series caps. These are fairly modern so I suspect some recapping has occurred.

Yes didn't spot those. Higher voltage rated axial packaged caps are becoming harder to find, the old stock new in the package capacitors or NOS can cause problems too - years of storage can degrade the dielectric materials. You can now buy modern made Chinese poly caps in axial form but they are usually a bright yellow colour ! I have noticed a Ebay seller here based in Canberra sells them in black.

In order to retain the original appearance, I have seen restorers resort to methods like drilling out the old caps and then placing a modern cap inside the old original.

[David Dunlop]

Hello Mike.

That may very likely end up being the way I go when it comes to a closer look at the paper caps in my 52-Set.

Have you ever noticed the cardboard ends on those old caps are folded in, in a manner very similar to what used to be accomplished with the reloading tools used with the old cardboard shotgun cartridges years ago? Down around the 410 size, or maybe even the cartridge size used in the wartime 2-inch Mortar rounds.

David

[David Dunlop]

Although the warmer weather re-activates all the exterior chores around ones home, it is still a perfect time to be sanding down old lead based paints outdoors. Better out than in they say, so I have now started restoration of my good Case, Spares for the 52-Set.

I thought it would be good to start with how the Case, Spares looks at the moment and these first three photos show the smaller left compartment which only has KimPak padding on the bottom of it (Not sure yet what was stored there.), the larger compartment on the right, which was fully padded and held the spare valves for the Main 52-Set, and the fully padded inside of the lid. Neither this Case, or my much rougher grey one, show any signs of a Contents List ever being glued anywhere on the inside. If anyone has such an original list, please contact me. It is possible this list my have existed in a free standing form as a folded sheet placed in the larger compartment with the valves.


David

[David Dunlop]

I think this Case, Spares is in such great shape because it was fortunate enough to have been stored somewhere very dry for most of its post-service life. The last known owner only ever used it to store spare valves in, in their original cardboard covers, and the case saw very little use once full, before passing it along to me. There has been some shrinkage of the Pine boards over the years, but nothing at all alarming, compared to my other grey Case, Spares that shows significant swelling and heaving of joints due to exposure to excessive moisture over the years. In fact, the shrinkage of the boards on this case ended up revealing a design feature I was not expecting at all, which was fun to discover.

The first photo of the lid shows some fine splits across the length of it, but these do not appear to have made it all the way through the wood.

The next two photos are of the back panel of the case. It was here that I first noticed the shrinkage had taken place. Note the four 1-inch Finishing Nails used to secure the partition board inside the case, at the left side. The wood has pulled back from around them a bit and it is just paint on the ends of these nails, no filler at all. This is consistent with what I suspected with the Box Tools when replacing its missing partition. The Finishing Nails were simply run flush to the wood and painted over to save time on the production line. I will have to tap these all flush again before I start sanding, however, or I will be shredding a lot of sanding materials.


David

[David Dunlop]

The first photo here shows the front of the case, with a few longitudinal splits and the ghosts of the factory original ID Stencil.

The second photo is the really interesting one to me. It is of the left end of the case showing a few splits that do not do all the way through the wood, but check out the edge of the bottom board. A beautiful example of the tongue and grooving used to built this board up to the required width. But check out the narrow board at the right end, just before the metal corner reinforcement. It has been double grooved. Strange.

The third photo is of the right end of the case. A few more shrinkage cracks, but there is also a pattern of staple marks in a roughly ‘File card’ sized pattern near the centre of this end, and these marks were filled by the last green coat of paint this case received. I will have to double check the other Boxes/Cases I have to see if they show any staple marks before filling these ones up.

The last photo is the bottom of the box showing where the strips of board used to build up this panel have pulled away from each other a bit and curled ever so slightly.

And that covers the starting condition of this particular Cases, Spares.



David

[David Dunlop]

I have now started the first part of the work needed to strip down the old paint from all the metal hardware.


David

[David Dunlop]

In spite of the seasonal obligations of Yard Work, Painting and upgrades, I have now got the metal hardware on the top of the Cases, Spares cleared of old paint.

The next step will be to do the left and right end panels.



David