WW2 Canadian Wireless Valve Testers

[David Dunlop]

All necessary socket holes on the cover have now been mapped out for drilling.

David

[David Dunlop]

One of the nice things about -30 Degree Winter Weather in these parts is the chance to putter on projects indoors.

To that end today, I was able to drill all the required holes in the adapter cover to hold the four British Valve Sockets.

Next step will be a coat of grey gloss enamel for the cover and let it cure up for a while.


David

[David Dunlop]

Now have a coat of gloss grey on the cover. It will have to cure for a bit and a couple of edges will need a touch up, but the important thing is the project is slowly moving ahead.

David

[David Dunlop]

Labelling on the cover plate, for the sockets, has now been completed.

Next step in this part of the project will be to get sockets installed on the cover. And if the weather ever warms up enough, I will see what can be done regarding the application of the finish wrinkle black paint for the case. The product recommends two or three quick, heavy (without running) coats of paint, followed by heat curing. The faster the paint cures, the better the result apparently. Since the case is plastic, my best bet at the moment, is rapid insertion in the kitchen oven set at 100 F. Assuming my lovely better half is off shopping for the day at that point in time.

David

[Bob Carriere]

When do you start production ....... I could use one for my tester.

...and how did you do such a nice job on the lettering...???

Bob C.

[David Dunlop]

Thank you for your nice comments, Bob.

I am not sure about production just yet. I am still on the dark side of all the wiring that will have to be done, but am looking forward to that challenge. The Wiring Diagram and photos Bruce McMillan posted will be a huge help in that phase.

As for the lettering, that is a product called ‘LETRASET Instant Lettering’ I actually purchased in 1976 at a local Drafting supply store, back in the day when the human brain reigned supreme and hand eye coordination a wonder. I was restoring my 1st M38CDN back then and needed a means to replicate the white ‘HIGH BEAM’ decal under the red indicator lamp on the Instrument Panel. The chap who ran our Drafting Office in the Geology Department at the UofM suggested I go and check the product out as they used a lot of it creating all sorts of geological maps for thesis publications and research papers.

I picked up several interesting sheets in white and black print and still have them, with original backing sheets and storage bags, sitting flat in a credenza drawer in our office here at home. I usually apply the lettering after measuring out where it all needs to go (usually several times) before the paint fully cures. It seems to bond really well doing that. You can apply a clear coat, but I only ever did that with the M38CDN lettering: a small rectangle surrounding the lettering to simulate a clear water transfer decal backing.

David

[Bob Carriere]

I had some from the office from years ago...... had a friend who worked in "form design" section and kept me supplied.

After many moves and eventual storage in a very hot attic my sheets were all spoiled..... I am sure that went away with the Dodo birds...... it sure was handy

Must be something available that can be done today on computers by printing on special decal sheets?????

Anybody has any suggestions...... for us to modernize!!!

Bob C.

[Grant Bowker]

It does seem Letraset has gone the way of the Dodo. (the forum spellchecker fails to recognize the name). These folks sell custom made rub transfer labelling https://imagetransfers.com/blog/how-...from-letraset/ I've never tried them but it seems an interesting concept.
Yes, it is possible to print your own water transfer decals (also called water-slide in some discussions). There are several catches to be aware of - printing white with inkjets (Alps used to make a printer that could print white) or lasers isn't the easiest, not all inkjets will work with water resistant ink.

[David Dunlop]

The valve sockets have now been mounted to the cover plate and the hardware secured with red lacquer (compliments of a sale on Revlon). The ID tags on the back of the cover are to remind me exactly what sockets I am working on when I get around to the actual wiring of them.

The last picture I could not resist taking as it is a bit of a sneak preview of how the finished assembly will look after the wrinkle black gets applied to the case.

I now need to get a final sort of the wiring on the original Stark adapter he owns from Bruce McMillan, and then the real fun can begin.

David

[David Dunlop]

Hello Bruce McMillan. It’s me again.

I am wondering this time if you can confirm some wiring information for me on your Stark adapter? I would like to try and match the colours used by Stark and if I match starting at the B9G socket, I will be working backwards to the Octal Plug and it can fall into place easily enough at that point.

(1) The cable I am working with has 8 coloured wires as follows: white, yellow, orange, red, green, blue, brown and black. I think 7 of those are a match for the wiring on the Stark. The exception should be my ‘white’ would be a purple wire on the Stark.
(2) What coloured wires start off from the Octal Plug to the pins of the B9G socket? That is the busiest socket for connections and once it is sorted, I can follow through with the other sockets easily enough from the wiring diagram and socket photo you provided earlier.
(3) Line 8 from the Octal Plug shows feeding to both Pin 5 and Pin 8 of the B9G socket and then off to Pin 8 on the Mazda Octal socket. I can see there is a jumper between Pins 5 and 8 on the B9G, but I cannot tell if the wire from the Octal Plug goes to Pin 5 first, jumps to Pin 8 and then to the Mazda, or if it starts at Pin 8, jumps to Pin 5 and then off to the Mazda. I suspect the former but need your observations of the original Stark.


If you can confirm the above three items for me Bruce, the wiring part of my work can begin.

Best regards,

David

[Bob Carriere]

I thought wiring my C15a was tricky and I had a new repro harness with all the correct colors!!!!!

I am waiting for the sssszzzzit Poof!!!!!

Make sure you work stool is isolated......

Bob C

[Bruce MacMillan]

From the plug:
pin 1 brown
pin 2 red
pin 3 orange
pin 4 yellow
pin 5 green
pin 6 blue
pin 7 purple
pin 8 grey

on the b9g socket
pin 1 brown
pin 2 red
pin 3 orange
pin 4 yellow
pin 5 jumper to pin 8
pin 6 blue
pin 7 purple
pin 8 grey
pin 9 green

all 8 wires from the plug go to the b9g socket.

it's interesting that this mod/add-on is official but no documentation has been found. Probably something base 202 workshop conjured up.

[David Dunlop]

Woot, woot!

That is fantastic, Bruce, thank you so much! I shall start mapping it all out on paper this weekend, and then the games can begin. I will substitute my white for the purple run and my black for the grey,

This is going to be fun, looking at the B9G and the Mazda again, I realized I am going to have to be careful in positioning the wire runs to avoid cutting across the bottom of the central locating pin holes, to avoid accidentally blocking them. Lots of considerations and care now.

David

[David Dunlop]

The Wrinkle Black paint finish has now been applied to the case. It came out with a very nice wrinkle on the bottom surface. The vertical sides are more of a Black Granite Crystal appearance, but that's OK.

David

[David Dunlop]

The rubber feet are now in place on the bottom of the case, the Protectors, Cable installed on the side and all the hardware locked in position.

I think it is starting to look rather business like now.

David

[David Dunlop]

The next phase of this project is going to be the wiring in of the four sockets.

Now that the colour coding for all the connections has been sorted out, I have to prep the 8-conductor cable at the adapter end. The cable I chose will be long enough to provide the final working cable assembly length needed, and the extra sections of wire needed to connect the three sockets following the B9G, which is the first socket in the sequence.

I had a choice in cable of either a cloth loomed one, or a black vinyl one similar to the Stark original. I chose a chocolate, brown, cloth, loomed cable only because I though it would be a more interesting match to all the cloth loomed connectors found with the 19-Set and 52-Set wartime accessories. The interesting challenge with a cloth loom, however, is the tendency of the loom to slowly unravel and fray back over time. As you can see in the attached photo, the length of cable I have had quietly sitting, awaiting its turn in the project for the last few months, is already coming apart, I could simply lacquer it, but I thought it would be much more interesting to go 'old school' and bind the end.

So at this point, the steps will be to measure the amount of free wire I will need for the 8 conductors to have them all link up with the terminals on the B9G socket and trim the loom back that distance accordingly. Then bind the end of the loom. I can them measure the amount of extra wire I need from the opposite end of the cable to provide the necessary bits to tie in the remaining three sockets and trim the cable.

I think the binding at the adapter end of the cable, once varnished, will also provide a useful anti-strain for the connections on the B9G socket, should the cable get an unnecessary tug down the road.

Then the soldering begins.

David

[David Dunlop]

This next sequence of photos shows the prepping of the adapter cable at the socket end of the system. I am not sure if there is an art, or science, to determining the most suitable length of conductor wires to work with or not. You have to just figure out a good length to work with that enables all socket terminals on the B9G to be reached easily, with enough room for soldering work, and at the other end of the spectrum, creating a rat’s nest! It doesn’t help that the actual cable end gets in the way and adds to the overall list of considerations.

The first two photos show the final length of free wires being determined and the cut point for the loom being marked off by a ring of masking tape. The winding of this tape is important to prevent the loom from fraying out of control before you are ready to deal with it.

Raiding Debbie’s sewing kit was a big help for this part of the work as she had a small set of very sharp, pointy nosed scissors that worked really well. I cut the loom back from the open end to the ring of tape and then snipped the loom away around the ring of tape. It is important not to tug on the loom too much as this will cause it to fray out from under the tape, despite your best intentions. Care should also be taken in this regard when unwrapping the tape.

The third photo shows the cable with the required amount of loom removed and you will notice a dark band on the first ¼-inch of loom. This is an application of clear nail polish to seal the end of the loom from any further unravelling. Nail polish is great for this as it dries very quickly.

Picture 4 shows the start of the binding process. I used a #10 Size Crochet Thread for this work. Pure cotton, and a 350 yard roll will only cost about $10.00 Cdn. I wanted about half an inch of binding, from the open end of the loom back up the cable. As shown, you start at the back end by tying a snug loop around the cable and knotting it on top where you can see it. The free end of the thread is laid out towards the end of the cable. Your first row of binding is going to cover this loose thread end up. You take your working end of the thread and start your first wrap of binding from the knot in your initial loop, the first pass going directly behind your initial loop. It is important here to keep a good tension on the thread as you are winding around the loom and keep each pass of thread directly up against the last one. Once you have made the first pass directly behind the initial loop and are back at the knot, cross over the knot and continue the winding process towards the open end of the loom. When you are about half way down the free end of the thread from tying the initial loop, you can trim off the excess of that free end and continue on towards the end of the loom. Once you reach the end of the loom, I usually just go far enough to cover the last fuzzy bit. At this point you then start winding a second row of binding, back towards your start point. When you are back at your start point, you return with a third and final layer of binding, back to the front of the loom. When you reach the front of the loom on the final layer, trim the binding thread to leave about ¼-inch of an open end. Then, while holding the binding with the thumb and finger of one hand, use a small, jeweller’s size slotted screw driver to tuck the loose binding thread end in under the front of the binding you have just completed. You can see this in the final photo, which also shows the last very important step. As soon as you have finished the binding, it will need a couple of coats varnish, or even better urethane clear coat. I prefer the urethane as it is a water based product and the binding thread is cotton. The cotton will get nice and wet and shrink even more snugly onto the cable as it cures. And that little loose end you tucked away will never come loose again.


David

[Bob Carriere]

.... I believe that Northern Electric is looking for guys like you......

Fantastic.

[Bruce MacMillan]

excellent workmanship David. Project coming along quite well.

I first learned how to lace back in the early 1970s working for BC Tel. This was pre nylon cable ties. Working on the main frames cables had to be dressed neatly, proper bends and all hand stitched with lacing twine.

If anyone here had visited Expo 86 in Vancouver in 1986 and visited the Russian building they would have seen more of this. They had a Soyuz capsule on display and cables were terminated with the same technique David is using.

[David Dunlop]

Thanks for the kind complements, Gentlemen. Much appreciated.

The last time I did any binding, or lacing, was some 30 years back on a 19-Set project. The binding work was for a Crystal Calibrator Dog Bone that somebody had cut the binding from where the calibrator supply line comes out of the one end socket. I could find no reason for the binding having been cut away, other than perhaps pure curiosity, so had the fun of restoring it.

I cannot recall why I got involved with lacing. I recall it was a short run of wiring, that again, had been snipped at for no clear reason. Not even sure if it was a 19-Set chassis, or something else at this point, but lacing was fun to sort out. I discovered very quickly, there is a right way of doing it, and a wrong way which looks all too similar to the correct way, but you discover too late its is indeed wrong and you have to replace it. And just to add to that wrinkle, there is actually a third, really good way, of lacing up a run of wires. I have a reference on the topic somewhere. I should probably dig it up and post one day, before circuit boards and AI completely take over.


David

[David Dunlop]

These three photos show the final stages of the socket wiring for the adapter. With this stage of the project finally completed, there was no further need for the socket reference tags on the underside of the cover, so off they came.

An interesting realization came about while working on the wiring. The start point at the B9G socket was going to be the most challenging to solder. It was the closest point to the cable assembly, which sooner, or later, was going to be a challenge to work around, for getting wires into terminal holes and staying there, while also manouvering a soldering iron and the solder. I had decided to simply start with Pin 1 and work my way in sequence to Pin 9 and all should be OK. That worked for the first two pins before two things came to light. The first was the anticipated issue of the cable itself getting in the way. The second was my mindset.

The adapter I was modeling mine after was the Stark design that Bruce MacMillan is lucky enough to have in his collection. I had been following the wiring runs in the Stark so closely for the first two pin runs I lost sight of the fact this original Stark was a much narrower design than the case I was working with. I was using very short runs of wire between the sockets, which were adding to the problems of the loose ends staying put before soldering them in place and ease of access for the soldering iron. At that point, the valve lit and I became a bit more generous with the wiring runs. You can see that transition in the first two photos.

The third photo was taken after the cable assembly was finally positioned and all the continuity checks, within and between the four sockets, checked out absolutely correctly (several times). This last photo turned up an interesting point.

If you look at the reflection of the camera flash around the cover screw in the lower left corner, you can see a ‘cone of depression’ around the screw. When I spotted this and looked more closely at the reflections around all six cover screws, four in total showed this cone around them: a result of the screws being over tightened. I backed them off just until the cones disappeared and then checked the seam between the cover and case and it was all still snug, but at least the excess stress on the plastic cover was now gone.

The next step will be prepping the cable end to which the Octal Plug will be fitted.

David

[David Dunlop]

I have not got as far along as I had hoped with this work lately. I have been playing tag with a kidney stone again for the last couple of weeks, Grrr!

As noted in the attached two photographs, however, I have been able to trim the cable to the required length, bind it at the appropriate spot at the Octal Plug end and install the Octal Plug Cover on the cable (oriented correctly).

This morning, I was able to trim the 8 conductors in the cable back enough they will extend about one quarter inch beyond the ends of the plug pins when fully seated for soldering in place. I have also been able to arrange the conductors in the correct circular sequence to line up with their corresponding pins on the Octal Plug.

Next step will be to tin the exposed copper stranding, and bend them all to line up with the plug pins. Then the actual soldering of the connectors to the Octal Plug can begin.

David

[David Dunlop]

Clearly I have not had to do a lot of tinning for quite a while. I could not find my small tin of rosin flux anywhere and ended up making a quick run yesterday morning to a local electronics shop to purchase a fresh tin of flux.

With that on the workbench this afternoon, I have now completed the tinning of the eight leads to the Octal Plug. While checking the plug itself for any issues, I finally noticed that whoever the manufacturer of this particular plug was, they took the time to cast in the pin numbers on both the top and bottom of the plug base. Nice touch, as not all manufacturers seem to do that.

I did notice one other thing, which made the close inspection worthwhile. There was a noticeable variation in the size of the openings on the tips of the pins. Not a huge variation, but just enough that only 5 of the eight leads would slide easily through the openings. I took a small steel scratch all from the tool bin and gently inserted it into each hole to match them all to the largest sized opening visible. It was a bit of a challenge getting all eight leads into their allotted pins at roughly the same time. Seven of the eight seated quite easily and as each went into place, I used a pair of small needle nose pliers to gently bend the leads a few degrees to the side of the pin tips to hold each in place until they can be soldered home. The yellow lead, which had the greatest distance to travel from the end of the cable loom to its final resting place, took a little nudging to get it far enough out of its pin end to grab with the pliers, fully seat and get its holding bend applied.

Next step will be the final soldering of the eight leads to the Octal Plug pins and then I will use a small stone on my Dremel to clear away the excess leads. But not before I quadruple check continuity between the Octal Plug pins and the sockets. I’ve made enough of those hasty mistakes over time, I don’t have any desire to purchase another T-shirt!

David

[David Dunlop]

Another productive day at the basement work bench this afternoon.

I was able to get the leads to the Octal Plug pins all successfully soldered in place, and the excess trimmed away. Then it was a simple case of using a small stone on the Dremel to smooth the pin tips up.

The actual real challenge was getting the Octal Plug Cover to snap in place. It did not look like much but was a tough little sucker to pop into its final position. I was pleased to see that when the anti strain clamp was finally run home, it ended up exactly where I had hoped it would, at the mid point of the loom binding. The final photo shows how this adapter fits up with my Precision 612 Tube Tester.

Now I just have to sort out two of the tester controls to see exactly what output they are providing, and to what pin locations. A third control, for the Filament Voltages, Precision actually provided a table of voltage values for in their manual, for the 18 available switch points. Since the ARP-3 Valve is the most common in the 52-Set, I will focus on it first. The pin information for the valve is readily available, so it will just be a case of testing each pin on the B7 socket for each switch point on the two controls to see what end values are delivered and when I get the correct values for each pin noting the control settings. It will be basically the same process for the 12Y4G valve on the 5-Pin Socket.


David

[David Dunlop]

I would like to thank, once again, Bruce MacMillan, for bringing the existence of the original Stark valve adapter to our attention and so generously taking the time to post all the necessary details needed to make this clone a possibility.

It is that kind of interaction on this forum among its members that makes this site such a great place!

David

[David Dunlop]

It is interesting how we sometimes miss little details when we plunge into trying to understand bigger issues. It also doesn’t help if we find ourselves juggling several bigger issues at the same time.

Since the Wireless Set No. 52 evolved out of a British design, and the British based valves were retained in that process for the wireless set, a means to test those valves becomes important, and hence the existence of this Stark designed British Valve Adapter which could be used with North American tube testers.

The ARP-3 pentode valve is by far the commenest in the 52-Set and the interesting thing about the manufacture of these valves in Canada during the war is that all of them are marked “ARP-3 EQUIVALENT”. The wording does not seem that significant at first glance, but it screams volumes when you take the time to think about it.

The original British Military ARP-3 is nothing more than a direct copy of the prewar commercial 9D2 pentode valve. There was nothing preventing a company in Canada from getting a licence to produce said valve in Canada. In which case, all those Canadian valves would have simply been marked “ARP-3”. However, tooling up for production would have taken time and money to accomplish. Time being the important factor at the start of WW2.

So something in the list of available pentode valves already in existence in North America must have been a close enough match to work as an ‘equivalent’ to the ARP-3, thereby saving a lot of time getting production up to speed.

As this adapter project came closer to completion, I started looking to see what the history of the ARP-3 was, which was tricky. Lots of data is on the web about the ARP-3 but this data and photos are nearly always of the Canadian Marconi ‘equivalents’. This last weekend, I finally ran across an early wartime Brimar publication and in it found the technical details for the commercial 9D2 valve the ARP-3 was based on. These specs matched the Canadian Marconi ARP-3 equivalent perfectly. In very small print at the end of the article it said. “For further description see the 6K7G.” That was an eye opener! The 6K7G is part of the tube set in the Wireless Set No.19.

When I pulled out my RCA tube guide for North American tubes, the data for the 6K7G was indeed a match for the 9D2, except for the Heater/Filament Voltage. The 6K7G was rated for only 6.3 Volts. The 9D2 and Marconi ARP-3 Equivalent were both 12.6 Volts. So then I checked the 12K7G pentode and there it was. Same specs AND the 12.6 Volt Heater/Filament rating. I then carefully traced out the octal pin arrangement for the 12K7G tube through the British Valve Adapter wiring diagram I had just worked on and arrived at the correct pin arrangement for the B7 British Valve Base. So now i know when the adapter is connected to my tube tester with the Marconi ARP-3 valve in place, I just have to set the tube tester to read a 12K7G tube and I am in business.

I was so pleased with this discovery, I sent an email to a friend in Quebec to tell him about it. His reply was, “Did I not tell you that last Summer in an email?”

After several minutes review of old emails on the computer, there it was. He had! But I had lost that little tidbit while wrapping my head around a bigger problem we had been working on.

Silly me.

David

[David Dunlop]

I have now been able to pull together the appropriate settings for my Precision Series 612 Tube Tester to enable me to test the ARP-3 Pentode valves for my 52-Set Project, using the British Valve Adapter I was able to build.

A long overdue Calibration Test of the tube tester revealed no serious problems, and i was able to do three consecutive tests of the same ARP-3 valve and get readings within two points for the three readings. Quite pleased with that.

David

[David Dunlop]

This is the second British Valve used in the 52-Set Receivers and it utilizes the British 5-Pin Socket. It took a little digging to sort out, during which I ran across four different versions of the pin numbering for the socket, including the incorrect drawings in the 52-Set manual schematics.

Only two of these valves are used in the receiver. one is a Noise Limiter and the other serves the AGC circuit. This can come in handy because if both valves get a good rating when tested, but either of these two circuits are not up to par, I can swap the two valves as a first check to see if anything improves.

As far as the settings needed on the Precision Series 612 Tube Tester to test the 12Y4, I am about half way through sorting out that data. The main settings turn out to be the same as needed for the 12H6 tube, so all I have left to do now is sort the correct switches for the five relevant pins. Should have that done tomorrow and then I will test one of my 12Y4's to see how it works out.

If all goes well, I will tabulate the settings for the two valves and try posting a copy here for future reference.

David

[David Dunlop]

There is a small correction required in the Stark Valve Adapter Schematic shown back in Post 6.

The wiring is absolutely, spot on correct, however the pin numbering for the 5-Pin Socket needs to have the "2" and "4" Labels switched as per the attached copy of a Brimar diagram illustrating the Base Connections of Valves for the three common British Valves.

You will notice that once the two noted pin numbers are corrected in the Stark Schematic, the wiring flow will read consistently across all four valve sockets.

David

[David Dunlop]

Just in case it might prove helpful to somebody else, I have attached a copy of the settings I have worked out for testing the ARP-3 and 12Y4G valves on a Precision Series 612 Tube Tester, using this Stark based valve adapter.

David