Wireless Set No. 52 Canadian - Project

[David Dunlop]

I had the Main Set Receiver over at a friends place this morning to have him mentor me through the alignment process for the RF Coils Assembly. I worked through the process twice and at the end of it the receiver now has signals booming in across all three bands. His part of town seems to have a lot less radio interference than mine does.

With the Main Set Receiver now back in the Carriers No. 4 and no longer deaf, I made an interesting discovery There is an open circuit somewhere in the Sender where the Aerial Feed passes though to the Receiver. When I bypassed the suspected problem area with a jumper cable, the receiver sprang to life with contact to my dipole aerial out back and WWV came booming in loud and clear on Band 3 at 10.0 MC on the dial. All sorts of other signals were to be found as well. Interesting that with the receiver completely deaf before the alignment work was done, I was completely oblivious to this problem.

The plan now is to bring the Remote Receiver up to this level of performance and then go back to the Sender. I have to complete the cleaning of oily soot from the lower chassis surrounding the 813 Valve Socket anyway and can take a closer look at the aerial circuit as well. I suspect it might be a problem in the Band Selector Switch but could also be the relay in there that disconnects the receiver from the aerial circuits when the set goes into transmit mode may be stuck open for some reason. Over all though, it was a great day!

David

[Chris Suslowicz]

Originally Posted by David Dunlop

With the Main Set Receiver now back in the Carriers No. 4 and no longer deaf, I made an interesting discovery There is an open circuit somewhere in the Sender where the Aerial Feed passes though to the Receiver. When I bypassed the suspected problem area with a jumper cable, the receiver sprang to life with contact to my dipole aerial out back and WWV came booming in loud and clear on Band 3 at 10.0 MC on the dial.
...
The plan now is to bring the Remote Receiver up to this level of performance and then go back to the Sender. I have to complete the cleaning of oily soot from the lower chassis surrounding the 813 Valve Socket anyway and can take a closer look at the aerial circuit as well. I suspect it might be a problem in the Band Selector Switch but could also be the relay in there that disconnects the receiver from the aerial circuits when the set goes into transmit mode may be stuck open for some reason.
David

The most likely culprit is the transmit/receive relay - either stuck in the transmit position or not making contact (dirty contacts) in receive. Another possibility is a short circuit somewhere in the aerial wiring or the gas protection tube is faulty.

But a great day nevertheless.

Chris.

[David Dunlop]

So this weekend is the time for me to align and calibrate the Remote Receiver for my 52-Set. First step will be doing the two IF Coil Assemblies and see where that leads things.

The RF Input Signal I will be using this time will come from my early 1950’s Stark Signal Generator. I tested it out a few days ago and found it is very well calibrated, compared to my Canadian Model SG-1 Signal Generator. I need an output signal of 420 Cycles with a 400-cycle modulation. 420 Cycles is well below the frequency range of the receivers I have on had, but I realized I should be able to tune in the 5th Harmonic of that signal at 2100 KC on the Remote Receiver. I was indeed able to find it and it was exactly at 2.10 MC on the Receiver Dial, which told me the 420 Cycle setting on the Signal Generator, was spot on.

Getting a test signal into the receiver is the start, but you need a good reference output to adjust to. The recommendation is to bypass the speaker entirely and use one of the Phone Sockets to put a meter across and tune t the optimum deflection on the meter.

As it turned out, one of the other vintage bits of test gear I have had sitting quietly on a shelf over the years is a 1945/46 SOLAR Model CF Exam-eter. Its primary claim to fame all those years ago was it was one of the first pieces of test gear that could accurately test capacitors while they were still fully connected to their circuits. Typically, without such a piece of test gear, one has to remove one end of the capacitor at the very least, or completely remove it to get an accurate reading. As well as testing capacitors, this Meter does all the other things a VTVM can do and more. What caught my eye when reading the manual last week was that this meter can be used for Alignment Work.

Since I am going to have to go though the alignment process with this receiver 2 to 3 times to really fine-tune it (and go back one more time to redo the Main Set Receiver). I thought a more permanent Test Lead would be in order, rather than jury-rigging something temporary.

What I came up with is built around what the Eagle Eye Wireless Owners out there will recognize and the cord from a Morse Key No. 9 that I had parted out some years back and if I ever need it for its original purpose again, it is very easily restored back to original condition.


David

[David Dunlop]

It is getting a little crowded on the work desk now.

From left to right in the attached photo are the Remote Supply, the Stark Signal Generator, the Remote Receiver and the Solar Exam-eter.

It will be interesting to see just how much this receiver has been played with in its past Life.

Although it can tune in stations across all three Bands, it is not as crisp as the Main Set Receiver now is, which is interesting because up until now, this Remote Receiver had been my performance bench mark.

What I have found interesting so far is if you try and tune any signal in to a ‘Zero Beat’ point, the top half of the Zero Beat cycle is chopped off and the bottom half seems much more extended than it should be. I am now somewhat curious if a prior owner was trying to retune this receiver to pick up lower sideband signals, but still have not wrapped my head completely around what is going on.


David

[David Dunlop]

A rather eclectic weekend of 52-Set work has just passed.

First and foremost, with the help of a lot of colourful muttering to myself, I was able to tune all the Trimmer Capacitors in the IF Coil and RF Coil Assemblies of the Remote Receiver. It helped a little bit, but not enough to get rid of the chopped Zero Beat Tuning phenomenon. I am going to have to bite the bullet and retune all the related coils. That will be a real challenge as two of them carry a HUGE amount of electrical potential and a proper insulated adjustment screwdriver is essential for that work. So I will have to schedule humping the Remote Receiver to my friend’s place down the road to finalize the adjustments this receiver needs.

With that out of the way, I decided to revisit the Sender to see why the aerial feed between it and the Receiver lacked continuity, so out that brute came from the Carriers No. 4 for a closer look.

A close inspection of the suspect Relay Switch proved it was in perfect working order and so was the Band Switch. That brought me back to the Aerial Output Socket on the Sender. I discovered two things there. First, the screw holding the Plug on the end of the Aerial Feed Cable was loose. Turned out an internal toothed lock washer was missing and the Plug was loose enough on the terminal fitting of the cable to produce intermittent isolation. Second, the Plug itself was a very loose fit in the Aerial Socket. Every other similar socket on hand produced a very snug fit for the Plug. By gently sliding a small slotted screwdriver between the four Socket Tabs and the Sockets large Bakelite housing, I was able to close up the gap for a much better Plug fit.

When getting ready to put the Sender back into the Carriers No. 4, I found the lower Shakeproof Cowl Pin on the Blower Door would not unlock. I have found it very helpful to have this door open when reinstalling the Sender in the Carriers No. 4. It provides easy access to the Sender chassis to nudge the Sender fully home. The two Knobs on the lower part of the Sender do not provide enough leverage to move the mass of the Sender in its upper portion where the two 8-Pin Connector Plugs need to link up. A careful look behind the Sender Panel revealed the Locking Pin in the Shaft of the Lower Shakeproof Fastener was falling out. I then remembered it was a much looser fit when installing it than the upper one. I was able to get it out and replace it, but this time let a little clear nail polish wick into the pin hole to hold it in place. Those two Shakeproof Cowl Fasteners on the Sender Blower Door still are a mystery. The upper one I have is shorter than the lower one and does not engage the Receptacle on the Sender Chassis at all. The lower one works just fine. Two more exist on the Receiver Section of the Supply Unit. The Parts List gives three Shakeproof Cowl Fasteners in use on the 52-Set but no reference at all to which ones go where. I am going to have to resort to a survey of all owners of surviving 52-Sets to determine what they have in their sets and see if some consistency turns up for working fasteners in both locations.

Once the Sender was back in the Carriers No. 4, I reconnected everything and fired it up once more. Happy Dance! I had full continuity from the Receiver all the way through to the dipole aerial outside. Even nicer to hear for the first time, were the changes in audio output in the Receiver when the Sender Band Switch was changed to and from the same Band at the Receiver was set to, and the three Tank Coils used in the Sender to tune it and the Receiver to the aerial in use, were finally working. Now I just have to get the Coils, Aerial Tuning No. 2A linked into the system.


David

[David Dunlop]

Several years back I had purchased a preassembled 12-foot Aerial Connector Cable Assembly for use with an FRG-7 I owned at the time. It was a run of RG-58A/U Coax with a UHF Plug at each end. The first time I tried it; the Central Conductor of one Plug jammed in its Socket and tore out of the Plug Assembly. A close inspection showed the Plugs used were cheap; using folded central pins, rather than rolled ones. The folding was off, creating one large sized face that stuck. Set the cable aside and forgot about it.

This morning I dug it out of a bin and decided to lop off the duff end and convert the cable to a small ring terminal at that end to allow for the future fitting of a turned brass PLUGS, Aerial. The type that sits at 90 degrees to its cable and has a cheese head BA screw holding it in place. I could then use this coax cable to connect either of my two 19-Sets, or my 52-Set to my external dipole aerial.

I got the job done this afternoon, and decided to see how the Main Set Receiver reacted to officially being connected to the dipole through all its proper fittings. I use ‘proper fittings’ carefully because at the moment, the Connector between the Sender Output Socket to the Coils, Aerial Tuning No. 2A, is about 4 times longer than it should be and that might be putting a bias into the works for a while.

It was so much fun listening to the WWV Time Signal at 5.0 MC slowly improves as the Sender and Coil Tuning came into play. I cannot help but wonder when the last time was, here in Winnipeg, when the Receiver of a complete 52-Set operated this way.

The three photos are of the cable I reworked for the task, the 52-Set up and running with all bits finally interacting and the output feed to the dipole on the wall, with the running CPP-2 Power Supply doing its thing on the lower shelf. If you look carefully in the last photo, you can see the output leads from the CPP-2 connected to the DC Voltage Distribution System I built for the Wireless Bench. On the back wall, just above the bench and between the two 19-Sets, you can also see the Battery Cable for the 52-Set connected to one of the 3 Distribution Boxes in the system.

A big thanks to Bruce Parker at this point once again for sending me the spare Coils, Aerial Tuning No. 2A he had on hand when I started this crazy project. Between it and what I had on hand, I now have a complete and functioning Coils and was even able to send a couple of spare bits to a fellow 52-Set Restorer in Northern Ireland to help with his work.


David

[David Dunlop]

This Project is at a very interesting point right now in that the pieces I have been working on for the last three years are finally interacting with each other to some degree. Kind of like when pieces of a vehicle start coming back together in a meaningful way. The timing for this is very good since I have to step away from the Receivers and Sender for a couple of weeks and I can take the time to review the work done to date to identify details I have missed, or not fully recognized the importance of, in my restoration work to date. For example, the noisy tuning coils in the Sender. I have now discovered these since the Receiver can once more interact with it as it as it was intended.

In addition to the three Aerial Loading Coils located in the Sender, there is also the much larger Coil, Aerial Tuning No, 2A that sits on top of the Carriers No. 4. The latter item is noisy throughout its tuning range, which is not the least bit surprising, since I have done no internal cleaning of that assembly at all so far, It will eventually be carefully disassembled, however, in order to restore the paintwork inside and outside of the wooden case, to return it to original Marconi Semi Flat Olive Green. At that time the Coil Assembly and its related WHEELS, “V” Contacts, will be fully cleaned.

As for the coils in the Sender, I did clean all of them of the sooty residue covering them, but did not pay as much attention as I should have to their related WHEELS, “V” Contacts. The result is intermittent scratchy spots on them as they tune throughout their ranges. The same effect as you hear on an old radio or television volume control that needs cleaning. What I think I will do in the interim is set the two sets of coils back to their start points of ‘0000’ on their Counters and then run them both full range, recording the Counter Values at every noisy section. Then, once I can get back to working on the Sender again, I will be able to find each spot on the coils that needs attention, as well as giving the WHEELS “V” a good cleaning.

The other thing I will be focusing on for a while will be a careful study of the actual Operating Procedures for the 52-Set. I need to be far more comfortable with the process than I currently am, and that only comes with reading, learning and practise. The Working Instructions Manual has good information for this but it does tend to be spread out through the manual a bit, which makes the flow of the information a bit choppy. On the bright side however, I discovered that some time ago, I had obtained a copy of the TELECOMMUNICATIONS FZ 523 1st Echelon Work for the Wireless Set No. 52 Canadian. Issue 1 dated February 1945.

This is an excellent training source, covering all the operating steps in a very nicely arranged sequence. It also has a wealth of useful Operators Reference material, troubleshooting information and Maintenance Data. One thing I did notice is you have to pay attention to what piece of the 52-Set they are discussing when it comes to working with the Meter, which is mounted in the Receiver, but services the Sender as well.

On the Receiver, the switch for the Meter is called the ‘METER SW.’, but on the Sender the switch is identified as ‘METER SWITCH’. In order to activate the METER SWITCH on the Sender, the METER SW on the Receiver has to be turned to ‘SENDER’.

See what I mean?


David