Wireless Set No. 52 Canadian - Project

[David Dunlop]

Hello Chris.

Interesting you should comment on the vibrator.

When I first took a look at the circuit diagram for the ZE-11 Supply, I assumed the two options for input (12V DC Battery, or, 115/230 V AC Mains) were fully exclusive of one another based on placement of the 6-pin Plug and the spring loaded switch setup. The current vibrator could very well be the factory original one. It is completely generic in look, with only “12 V” and the Canadian Marconi Part Number stencilled on the end of it in black block letters. It is also dead.

I did not worry too much about the vibrator status as I reasoned that since it was isolated by choosing the AC Mode of operation, and my sole intent was to be using the ZE-11 as a Mains based supply for the Remote Receiver, all would be OK.

Having solved the C25A/B capacitor problem and knowing I now had a good working OZ4 in the system, everything checked out OK downstream of the OZ4 socket. But when connected to the AC Mains, I now discovered the input voltages to pins 3 and 5 of the OZ4 are not matched. I am getting 200V AC on one side and 150V AC on the other. Should be 200V each. The end result is just 7 V DC at the HT pin on the Jones Socket, instead of the expected 150 V. I am also getting strange, intermittent voltage spikes ranging randomly from 10 to 51 volts, with an immediate return to the baseline 7 volts.

The first two things that came to mind were that the secondary windings on the transformer for the AC side had gone, but it was also possible that one of the RF Choke pairing L13A, L13B had shorted. The only way I can see to test which option is correct is to dismount the RF Choke can on the side of the chassis to exposed the two terminals feeding from the transformer. If the two feeds from the transformer are feeding 200 volts AC, then one of the chokes has failed. Worst case scenario, the secondary on the transformer is shot.

Then it crossed my mind the dead vibrator might be a factor, if it is still active in some way even when the supply is in AC Mode. Still trying to sort that out in my head. The price I am paying from being away from electronics for 30 years. I do know that if the vibrator is in the socket, or removed, there is no change in the results I am getting at the Jones Socket. A good working order vibrator could clarify that for me. The manual specs it out as follows:

VIBRATORS, Non-Sync. 12V, 4-Amp 1-1/2 inch diam, 3-1/4 inch long.

Not sure off the top of my head if that is a match for the one used in the 19-Set Supply, but it is a convenient point to take some time to mull over, with a stiff drink.

David

[Bruce MacMillan]

Looking at the xfmr secondary the centre tap goes to ground. Unplug the OZ4 and measure resistance from pins 3 & 5 to ground. This will include the resistance of the chokes. I wouldn't think there should be a lot of difference. If there is then disconnect the chokes and measure the voltage on the xfmr secondary to see if different. Hopefully not a shorted winding.

The DC side is separate from the AC side with the exception of R35A and R35B loading the vibrator winding to ground. The schematic shows each is 300R 5%. A good vibrator has no effect when running with AC and that is why it can be left in situ.

The primary side of this psu is almost identical to the VP-3 psu used with the Marconi CSR5 receiver. Vibrator used is nonsynchronous 115 cycle p/n 111-131.

[David Dunlop]

Thanks for clarifying the status of the vibrator in the overall system, Bruce. I will ignore it for the time being.

I pulled the OZ4 and checked the input to it on pins 3 and 5. Pin 3 was 200 VAC. Pin 5 was 150 VAC. As I reached under the supply to switch it off, I caught a bit of movement under some of the wiring. Loose bits wreaking havoc perhaps? When I turned the supply upright and gave it a careful shake over the bench, a small, oxidized blob of solder, along with several blobs of what looked like molten graphite fell out. I then blew the chassis with the air gun to make sure nothing else was still hiding.

When I then repeated the aforementioned test, I got 200 VAC on both Pin 3 and Pin 5. With the OZ4 still out, and the supply turned off I decided to double check the output from Pin 8 on the OZ4 to the HT terminal on the Jones Plug. A DC Voltage sweep from 10 to 150 Volts fed into Pin 8 was mirrored perfectly at the Jones Plug.

Next step was to reinstall all three OZ4s I have, fire up the supply and see what HT outputs arrived at the Jones Plug for each of them. Two had a ‘Nil’ result, the third gave me 7 VDC.

Looks like checked and matched OZ4s and OZ4As are readily available on eBay. Will have to pick a few up and try them out. From what I can now see with this ZE-11, a good OZ4/A should bring the AC Side of the supply to life just fine.

David

[David Dunlop]

Hmmm.

There is also the possibility I get 200 VAC both sides under a no load condition with the OZ4 out of the system, but add it back and something upstream suddenly cannot handle it.


David

[David Dunlop]

This project is an interesting one on a number of levels, not the least of which is making it work with a limited budget. To that end, at the very beginning, I decided to put together a list of what was required to make the project possible. It became evident very quickly that some items were more important than others, so an A-List and a B-List of required items were developed.

Obviously, the A-List had to include the five basic components of the Main 52-Set Assembly: Receiver, PSU, Sender, Carriers No.4 and ATU. In addition, a Remote Receiver, Remote Supply and relevant Connector Cable were added to this list at critical items.

The B-List became essentially the three Cases/Boxes used for tools, spare parts and the items for the Remote Receiver System. All the accessories common to the 19-Set, and the specialty cables and connectors were added to this list as well as the necessary tools and spares.

Restoration work has been focusing up until now on getting the Remote Supply up and running in order to facilitate getting the two receivers in the complete basic 52-Set up and running. That has been going relatively smoothly but work has reached a point where a lot of little fiddly things need attention, and in most cases, purchases of items to continue with the Remote Supply restoration. A point has been reached, however, where continuing to chase parts for this portion of the project can negatively influence the critical focus of obtaining the A-List items.

They say exceptions prove the rule. Well, I think that is true. I received an email from Jordan Baker a couple of weeks ago telling me he had spotted an interesting box at a location he had recently visited and upon closer inspection, it turned out to be the wooden tool box for the main 52-Set, so he purchased it and got in touch with me. Something had made me set aside the Remote Supply work for the time being just a few days prior to Jordan’s email. True, the box is not on the A-List, but it was one of the three critical, high priority items on my B-List, so I purchased it from Jordan.

It arrived in the mail Monday afternoon and is in very nice condition. A wooden partition on the left hand side has been removed (with considerable care) and will be an easy piece to replicate and replace. I even have a supply of the correct sized finishing nails needed. A metal bracket has been removed from the right rear inner wall, just below the right hinge. Looks like a single piece of hardware held it in place. Form and function remain a mystery for the time being.

Finish is the same OD Green Marconi used on the WS-No. 9 equipment and the Crystal Calibrator for the 19-Set. The two latches are identical to the ones used to secure the cover on the ZE-11 and ZE-12 Remote Supplies and the metal handle on the lid of the box is identical to the two Marconi used on the sides of the Remote Receiver Case. Post War NATO Green paint has been applied to the outside of this box at some point in time, but I can see traces of white markings showing through on the front of the box that will get a closer look shortly.

The photos are courtesy of Jordan, by the way.

David

[David Dunlop]

I did some careful cleaning away of the NATO Green paint on the front of my 52-Set Tool Box the other day and was delighted to find the original factory stencils still readable on top of the OD Green wartime paint.

The stencil was in 1/2 inch high by 3/8 inch wide Gothic lettering. The bottom of the first line is 2 inches below the lip of the box and centered between the hinges. This was followed by a blank line.

The second line of text is centered exactly between the inner faces of the two latch levers, and the last line centers directly beneath the second line. The entire stencil reads as follows:



ZA/CAN 4727

BOXES, TOOL, NO 1, WS
CDN NO 52


All of this was over-painted, as mentioned with NATO Green at some point and then the following, very simplified stencil done in ¾ inch high by ½ inch wide Gothic lettering:



Z1 ZA/CAN 4727


This line was centered on the lower rivet below the right hand latch assembly.

And finally:



BOXES,

This line was centered 1 and 3/8 inches above the bottom of the box.


Quite an exciting find, I thought. To be sure nothing was missing, I decided to check the photograph of the 52-Set Equipment in the manual, since all three wooden boxes/case are shown in it and although small, the stencils are quite readable.

Imagine my surprise when I discovered these markings read as follows:


CMC 113-547
ZA/C 00101
WIRELESS SET
CANADIAN NO. 52,
BOX, TOOLS

I then checked the scale line drawings and the descriptions in the parts listings in the back of the manual. All verified this information, and the manual was dated 9 May 1944.

I then remembered the Master Parts List publication for the 52-Set was dated 15 February 1945, so decided to take a look at what it had to show and tell. The same scale line drawings showed up, but the description of the item read as follows:


BOXES, Tool, No. 1 WS Cdn No 52


And the ZA Number below the drawing had changed from ZA/C 00101 to ZA/CAN 4727.

Finding production information, with thanks to CD Howe and the closing of Marconi, is a major challenge. Little Military documentation has surfaced to date that makes sense of the numbers on the military books and the serial numbers on surviving 52-Set components. Even if serial numbers were a continuation of No. 9 Set production, they seem rather high. The colour of the sets seems to have started out as a continuation of the OD Green from the No. 9 Sets and then shifted to No. 2 Brown, only to return to OD Green in later production.

The markings variation I have run across with this tool box seems to support that late production was OD Green. Somewhere between assembly and printing of the manual on 8 May 1944 and the publication of the Master Parts List 15 February 1945, the ID of this tool box has definitely changed. So early and late versions do exist. Be nice to find more original examples and see what base colours they have. I am now curious what markings any surviving No. 2 Brown tool boxes may have on them.


David

[Jordan Baker]

Glad it found a good home.

[Tim Bell]

Originally Posted by David Dunlop

The B-List became essentially the three Cases/Boxes used for tools, spare parts
David

Nice find... I have these for the WS9... pretty sure they are all the same.

Would be nice to see a close up of the parts list.

Tim

[David Dunlop]

How's this, Tim?

The bit missing from the bottom is sitting inside the box. I will add it back in once the box is refurbished. I am thinking of leaving the interior as is and just redoing the exterior in original OD Green. I will try and age the replacement wood divider inside to blend in, as well as the missing metal bracket once I get it sorted out.

Again, this picture is courtesy of Jordan Baker. I suspect he can weld, eat lunch and take photos all at the same time!

By the way, Tim, what sort of handle does your Cases Spare Valves & Parts have for the WS No. 9? The reason I ask is the photo in the Canadian 52-Set manual of the major items of the complete station shows the Case Spare Valves & Parts as having a fixed, leather strap style handle. The only such case I have seen here in Canada has the same metal style handle as on my Boxes Tool. I am thinking the leather handle on the Cases Spare Valves & Parts that Marconi used in the 8 May 1944 manual might be a carryover from No. 9 Set production until the metal handle version became available. They did that with the Remote Supply Units, shipping ZE-11's initially, until the ZE-12 production for the 52-Set was up and running.

David

[David Dunlop]

While currently on a bit of a break from component hunting for the 52-Set, I have been once again reading over the manual, and other documentation on this set. This has been a very interesting read, both the information that is available, and the information that is not.

The primary manual for this wireless is the WORKING INSTRUCTIONS WIRELESS SETS, CANADIAN NO. 52 VEHICLE AND GROUND STATIONS, dated 8th May, 1944. The first, notable impression one gets from this manual is that it is almost twice as thick as the one published for the Canadian Wireless Set No. 19 Mk III (a very well written manual in its own right). This first impression, combined with the current, perceived reputation that the 52-Set was difficult to work with, puts one in high alert mode as far as expectations for the read are concerned. This concern relaxes fairly quickly, however, once the read begins.

The style of writing is very similar to the Canadian 19-Set publication. The information is well laid out in a very logical flow and one cannot help but get a sense that the wartime wireless operators were a very well trained group of individuals. Not just in how to operate a wireless set, but in enough electronics background to understand the basics of what is going on inside the set, and during use, for trouble shooting and basic maintenance in the field. Even a nice sprinkle of humour on occasion, both written and illustrated.

What is really interesting about this 52-Set manual is how comprehensive and self contained it is with regards to the information it provided the operator. In addition to the expected step by step instructions on assembly, operation and basic field servicing and maintenance of the 52-Set and its components, relevant extracts from the manuals for the Charging Sets 300 Watt Mk I Canadian, Wireless Remote Control Unit No.1 (Canadian), Switchboard, Charging No. C5 and Antennae, Vertical, 34’ Steel Mk I Complete Kit are also provided. This is a valuable document for any 52-Set Wireless Operator. It has earned its metal stowage box on the top left of the Carrier No. 4 for the 52-Set. That brings us to the other interesting information about the 52-Set. The documentation that does not exist, or has yet to be found.

74 years on from the introduction of the 52-Set, a key piece of missing documentation to those of us now attempting to restore one of these sets today, is the detailed repair and rebuild information typically found in the Second to Fourth Echelon Work Instructions published by the military. An Issue 1 Canadian Army EME Manual, dated February, 1945, does exist for this document, but it is only 84 pages long, and apart from a dozen or so pages dealing with a general inspection and alignment procedures for the set, the bulk of this document deals with building and specifications for all the coils and chokes used throughout the Wireless Set No. 52. Unlike the 300 plus pages of the similar document for the 19-Set Mk III, nothing at all on repair and rebuild of any of the components for the 52-Set. Odd, considering this wireless set served into the early 1960’s in Canada. Maybe there were enough spare components in stores that broken sets were simply replaced and the duff ones tossed.

Chatting recently with Reg Hodgson in Edmonton, I learned he has been searching for a number of years for the installation instructions for the 52-Set in the White M3 Scout Car, with no luck. That initially struck me as odd. Reg has been well connected in the military vehicle sector for decades. He should have no trouble flushing such an installation manual out of the woodwork, original or copy. Then I remembered the introductory comments in the 52-Set Manual regarding interchangability of the 52-Set. Since it was a direct derivative of the Wireless Set Canadian No. 9 Mk I, its Carrier and mounting arrangement is identical to the earlier set, with one minor exception. The metal electrical connection conduit box running along the upper back portion of the Carrier No. 4 of the 52-Set adds 11/16th of an inch to the depth of the set. As long as there is sufficient clearance at the back of a pre-existing No. 9 Set installation, the Wireless Set No. 9 Mk I and its Carrier are simply removed and the 52-Set and Carrier No. 4 installed in it’s place. So on the face of it, it appears no wartime installation instructions for the 52-Set were needed, or published. That would mean today, if one wants to install a 52-Set in a particular wartime vehicle, one needs to find the installation information for the Wireless Set Canadian No. 9 Mk I, for the vehicle in question, and substitute the 52-Set in the installation. There is an interesting exception to this, however, the C15TA Armoured Truck.

A document exists, dated 8 April 1945, which combines information on how to modify the C15TA to fit inside the Hamilcar X (the twin engine version of the earlier heavy lift glider) and how to install a WS 19HP and WS 52 (CDN) combination setup in the C15TA. I call this a document as referring to it as an Installation Instruction Manual would be a huge stretch. If you would like to review a copy of this document, you can join the Wireless-Set-No19 Group in the UK and download a copy from their archive (Document # 2070). What you will find is what one might almost expect a publisher would get to polish up for printing and then some. It consists of some pages of rough, typewritten text, photographs of a sample C15TA vehicle installation for the two sets, with parts identification overlays for where everything is to be located and machinists drawings of all the necessary metal racks and brackets needed to complete the wireless installations for the two sets. The vehicle in the photographs must have been in Canada somewhere (or perhaps England) for documentation purposes. But clearly this vehicle installation was intended as a task to be done in the field somewhere, building everything needed from supplies at hand. No fancy kits from Canada required. Probably a great example of how the rapidly changing dynamics of the war post D-Day meant waiting for things to be produced at home just wasn’t going to work anymore.

My apologies for the length of this post, but as I said at the beginning, these 52-Set documents make for an interesting read, I thought was worth sharing.

David

[Barry Churcher]

David, here are a couple of photos of the C15TA installation that you are referring to. I would like to do the 19 set part of the installation on my truck but I don't have a 52 set for the rest. There are a couple of variations of this, for example the chore horses mounted on each front fender or both mounted on the rear wall.
Cheers,
Barry

[David Dunlop]

That latter photo is interesting, Barry. Looks as if they took advantage, somewhat, of the pre-existing jerry can rack. I wonder where the jerry cans were relocated to?

David

[David Dunlop]

Just having a closer look at the first photo you posted in Post 71, Barry. Good resolution in it and it shows the long rectangular connector box on the back of the Carrier No.4 quite nicely. First look I have had of that particular bit.

Also of interest is the top of the waterproof cover mounted along the top front of the Carrier No. 4. Looks like it is fastened to the carrier top by 5 lift the dot style fasteners with two straps to secure it when rolled up out of the way. That is interesting because the description of this item in the 52-Set Master Parts List suggests the cover is fastened along the top of the entire top edge of the carrier by a piece of flat steel bar. Unless, perhaps the steel bar is sewn into the lower edge of the cover to hold it down when in the lowered position.

Another thing to add to the further research list I guess.

David

[Chris Suslowicz]

Originally Posted by David Dunlop

74 years on from the introduction of the 52-Set, a key piece of missing documentation to those of us now attempting to restore one of these sets today, is the detailed repair and rebuild information typically found in the Second to Fourth Echelon Work Instructions published by the military. An Issue 1 Canadian Army EME Manual, dated February, 1945, does exist for this document, but it is only 84 pages long, and apart from a dozen or so pages dealing with a general inspection and alignment procedures for the set, the bulk of this document deals with building and specifications for all the coils and chokes used throughout the Wireless Set No. 52. Unlike the 300 plus pages of the similar document for the 19-Set Mk III, nothing at all on repair and rebuild of any of the components for the 52-Set. Odd, considering this wireless set served into the early 1960’s in Canada. Maybe there were enough spare components in stores that broken sets were simply replaced and the duff ones tossed.

The EMER set is almost certainly complete, and is all there ever was. Fourth echelon maintenance was "Base Workshops" who would have had the full complement of spare parts (as listed in the Identification List) available and were entirely capable of reducing the set to its component parts and rebuilding it from scratch. (This was done, post-WW2 when sets were rewired with PVC insulation, tropicalised, and reissued - particularly 19 sets that came out of Newark (near Nottingham, UK) with new paint and "NEW/mmyy" date markings on the (refinished) front panels.)

The lack of detail in the WS52 EMER is most likely because it used parts (such as the Condenser Drive assembly) common to the WS19 so there was no point in duplicating that - workshops would be completely familiar with it.

Various components were also supplied as sub-assemblies, e,g. the WS19 PA tuning mechanism as a complete unit from the flick mechanism back to the mica capacitors mounted to the rear of the tuning capacitor. That would save a lot of time if one had to be changed due to severe damage.

The coil winding details are in the 2nd-4th echelon repair EMER because that was a relatively simple repair job, and they had the equipment to do it. (They also had the equipment for rebuilding dynamotor armatures (rewinding and varnish impregnating), though I suspect that was an "only when there's nothing else going on" task.

Chris.

[David Dunlop]

Well now that I have calmed down after all the Edmonton excitement, I can return once again to my real little world. Sigh,

I popped the back cover off the Aerial Coil box to compare the No. 2 Brown paint inside to two other examples I have available: a 1944 Northern Electric Variometer for the 19-Set and an unknown 19-Set Spare Parts Case. Interestingly, although the two 19-Set items look more of a semi-gloss original finish than the interior of the 52-Set Aerial Coil box, all three samples seem to have aged similarly.

One can definitely rule out UV damage to the inside of the aerial box, so the generally universal fading of the paint pigments over time must be a result of oxidation breakdown of the pigments.

I wet down a small patch on each piece and it would appear all three actually come quite close to one another in the wet state. My thought process at this point is to use the wooden back plate from the Aerial Coil box for my matching sample when it comes to getting the paint and to have the match done to the paint when it is wetted down. My logic, and it may very well be flawed, is that the newly made up can of paint will be wet and will typically dry a tone or so lighter. If I match to a dry paint sample, the end result will dry even lighter.

David

[David Dunlop]

Been communicating recently with the Canadian Army Directorate of History (DHH) in Ottawa about the 52-Set. They can find nothing in their archives at all by way of a comprehensive set of repair and rebuild instructions. Nor is there anything suggesting work of such nature was or was not carried out by Canadian Marconi.

However, they did discover a great deal of 52-Set information is scattered around the LAC files that takes a bit of creative searching to track down. Topics like 'wireless' and '52' and anything else you can think of are worth trying. On line that can get you to files which one can then order copies of from the LAC.

A couple found are as follows:

"Standardization - Materiel - Ground Radios - Cdn Wireless Set 52 - United States Radio Set AN-GRC-19, - United Kingdom Wireless Set C-11"

Not sure what those three sets have in common, but an interesting grouping.

The other item was:

"Equipment and stores - Design Development and Research Project 1958 - Truck utility 1/4-ton M38 Canadian - installation of Wireless Set No. 52 Canadian and Ground Station"

Yikes! The poor ass end on that jeep would have been dragging like an overloaded classic VW Beetle!


David

[David Dunlop]

Been looking through the manual to try and identify the single conductor cable that runs from the Receiver, up through a series of eyebolts along the top of the three main components and into the Sender, to allow these two items to play well together.

Can anyone confirm that I have got it right with the above title? Probably going to have to track one of these cables down, sooner or later.

David

[Colin Alford]

David,

Here is a link to the CMHQ London files that were compiled on the Wireless Set No. 52 Canadian.

This link should get you to the first page and then you will have a lot of clicking to do to get through the hundreds of pages. Hopefully you will find some interesting information.

http://heritage.canadiana.ca/view/oo...7/1063?r=0&s=1

Regards,
Colin

[Chris Suslowicz]

Originally Posted by David Dunlop

Been looking through the manual to try and identify the single conductor cable that runs from the Receiver, up through a series of eyebolts along the top of the three main components and into the Sender, to allow these two items to play well together.

Can anyone confirm that I have got it right with the above title? Probably going to have to track one of these cables down, sooner or later.

David

Ah, now I was R-ing TFM in an idle moment and thought "that will be in the Identification List", and so it is. (It also gives you enough description to make one up if you so desire.)

-----------------------------------------

LEADS, Aerial, 25.3/4-in lg, No.C1

No.16 B&S stranded wire, rubber covered to 7mm dia; metal sleeve and tip on each end; early parts were wrongly labelled "LEADS, Aerial, No. C7 -- ZA/C 00105"; this label should be ignored.

NOTE: Spares are available for this item although not shown in station spare parts list.

ZA/CAN 4703

-----------------------------------------

(Page 5 of FZ526, which has an illustration of the item - showing the incorrect label!)

Best regards,
Chris. (Still looking for valveholders - but there's a radio rally on Sunday so I might have more luck there. I have found two B7 sockets but they're the fragile Paxolin type, I'd prefer the moulded variety.)

[Chris Suslowicz]

Originally Posted by David Dunlop

A couple found are as follows:

"Standardization - Materiel - Ground Radios - Cdn Wireless Set 52 - United States Radio Set AN-GRC-19, - United Kingdom Wireless Set C-11"

Not sure what those three sets have in common, but an interesting grouping.
David

Those are the "Role" sets for "Rear Link" operation by Signals personnel, I think:

Canada - WS52
USA - AN/GRC-19
UK - C11/R210 (replacing the WS19HP and/or WS52)

Chris.

[cmp truck]

Colin,
You have to buy a subscription to these archives.
Do you have a subscription and do you find it valuable?
The obvious usage would be material on vehicles and radios especially manuals and technical orders.
Regards,
Ian
VA6SSV

[Bruce MacMillan]

You don't need a subscription to browse the files. The subscription gives you a search function. I did buy a month's worth of time to see if was worth it but their indexing isn't very good. Colin's link has a lot of wireless info and if you're insomniac there's almost 6000 pages in that file to go through. That is only one of several hundred files. Some of it is interesting.

There is also info in these files on military vehicle design & procurement.

[Colin Alford]

Ian,

As Bruce mentioned, you do not require a subscription to view the files.

The subscription contributes to the project of digitizing the files and hosting them on-line and it allows for full text searching of those files which have this function enabled. Unfortunately so far none of the military files have the text searching function enabled.

I do not have a subscription and I find the information available extremely valuable. The problem is that it takes a long time to find the files that are of interest and then a very long time to click through and read each of the images to discover the information.

Colin

[David Dunlop]

Ian, I would be quite surprised to find manuals and that sort of material in this 52-Set file. It is basically a correspondence file holding the letters and telegrams etc that dealt with design, production and supply issues of the set. And as Colin and Bruce pointed out, it is a huge file with no sort capability.

I did notice a chronological order to a section I poked into but that may not relate to the entire file, just the small block I happened to be looking at perhaps.

As luck would have it, the topic of discussion happened to be the failure of the dynamotors. Only 10% of a very large sample had failed outright and it was determined not to have been overheating. They had narrowed the problem down to a significant fluctuation in the 12 volt input voltage which the dynamotors could not handle over prolonged periods. Efforts were being made to divert sets from a pending shipment to the Canadian Army to Marconi so they could investigate further, regarding this voltage instability. The Marconi address was odd. Possibly the operation in England.

David

[David Dunlop]

Well, enough rest and relaxation. I have stepped away from this project long enough.

I have been able to confirm the dead 12 Volt vibrator in the ZE-11 Remote Supply, although a Marconi product, is the wrong model for this supply. On the bright side, however, a couple of NOS, correct, original Marconi vibrators have been located, so with luck I can see what the DC side of this supply unit behaves like shortly.

I have also ordered a pair of NOS OZ4A rectifiers, so I can have another go at getting the AC side sorted out.

David

[David Dunlop]

The new OZ4A’s and rectifiers arrived in this morning’s Post, so some renewed testing of the remote supply will be on the agenda this weekend. Good thing, as +37 outside is simply not my cup of tea!

David

[David Dunlop]

Well, I ran some more testing on the weekend.

The good news is that, based on a modern input voltage of 120 Volts AC, everything in the Remote Supply up to and including the new OZ4A is doing exactly what it should be. Theoretical calculations match real time results.

On the down side, the HT output at the Jones Socket is running too high. A small part of that problem lies in the fact the wartime test specs are based on an input voltage of 115 Volts AC, which automatically produces slightly lower numbers down the line.

Looks like I am going to have to go in and measure the voltage above and below each remaining component in the circuit ( four caps and two coils ). Then compare those real results to the calculated results of each component, based on their individual specs.

David

[David Dunlop]

A major milestone has been reached.

After a couple of individuals pointed out it is necessary to load the output Jones Socket on the ZE-11 and ZE-12 Supplies with an appropriate resistance in order to get the true output, I did the obvious. I reread the test instructions for these supplies. There they were. A 3000 Ohm resistor was needed to jump the two HT terminals and an 8 Ohm resistor across the LT terminals. The readings are taken across each resistor. And both readings dropped right into the stated specification range.

Finally, with a fully operational Remote Supply I can now complete the cleaning and inspection stage of the Remote Receiver and see what it is up to.

David

[David Dunlop]

Cleanup and inspection of the Remote Receiver was completed this week, short of currently not yet being able to test any of the valves in it. So some may be weak or dead. Fingers crossed in that regard for the time being.

Before anything else, I cleaned the Connector Plug No. 1, checked it visually for anything obvious and hooked it up to the Remote Supply to test the continuity of it with the supply. Output was perfect so next step was connection of the Connector Plug to the Remote Receiver and turn the supply on.

The only thing that happened was a soft, steady hum from the speaker that was appropriately interrupted when the selector switch was toggled between 'SPEAKER" and "PHONES". No Indicator Lamp, or Meter readings and no response from the Calibrator when turned on. Supply 'off' and think for a bit.

I then pulled out my tired looking parts receiver and decided to hook it up to the supply after a quick inspection and see what it did when activated. How sweet. When the supply was turned on the Receiver On lamp lit and the HT reading on the Meter jumped to 160 and slowly dropped to around the 155 mark. Switched on the calibrator and it's lamp lit. And the meter readout dropped another couple of needle widths closer to 150 Volts.

That got me thinking the problem with the Remote Receiver must be close to the Input Socket since the inactivity of the set was so comprehensive. I could not see anything out of the ordinary around the socket assembly, but did notice that the three countersunk, slot head screws that mount the socket assembly to the chassis all had damaged slots, strongly suggesting somebody had it off at one time. So I pulled the screws and took a look behind the assembly. First thing I noticed was an unconnected wire waving at me. A careful check of all terminals at the back of the socket compared to those on the working backup supply, confirmed where the wire had broken loose from. Out came the jumper cables, as per the attached photo.

With ground for the socket assembly jumpered, along with the broken connection, I turned the Remote Supply back on. Happy Dance! The Meter came to life with the correct HT reading, the receiver lamp lit and so did the calibrator lamp when activated.

Seems a soldering project is in store this afternoon!

David

[David Dunlop]

While I think of it, has anyone had experience disassembling the large Bakelite Connector Sockets on this equipment? It is hanging down with the supply plug attached to it in the last photo, but a better view is in Post #28 of this thread.

One of the contacts had been broken off on this Remote Receiver, and there is a large relay mounted on the back of it that would have to be unscrewed. I am curious if replacing the broken contact would be a purely mechanical process or if a soldering iron is required. A large, heavy duty terminal strip runs along the inside lower end of the socket that likely feeds to the individual contacts. My guess is these contacts are probably mounted via screws to their respective terminals.

David