Wireless Set No. 52 Canadian - Project

[David Dunlop]

A somewhat stressful but positively productive day today so far.

As per the attached photos, I was able to remove the Sharp/Flat Switch Knob and release the switch from the chassis with no problem. It then hung quite nicely below the Coil Assembly I needed to work on. The six retaining screws for the Coil Assembly came out very easily, probably because they had been loosened up a bit when the two Coil Assemblies were upgraded. By comparison, there was a lot of factory, original varnish on the two mounting screws for the Sharp/Flat Switch and it took a careful increase in turning the screwdriver to pop them free.

The Coil Assembly I had to work on slid out quite easily with the anticipated resistance as the sleeves on the Rotator Terminal strips rubbed the edges of the holes. It was easy enough to give them a gentle squeeze with one hand while guiding the Coil Assembly free with the other.

I stacked some 2 x 4 bits up on the bench and topped them off with a portable bench vice at a height the Coil Assembly could rest against once free of the rear chassis wall. This left it at a nice working angle, leaving both hands free to attend to the necessary details.

You can see how wide open the gaps are between the capacitor plates after the spring tension released when the retaining nut broke, jamming them against each other. I then cut the two connecting leads to the Trimmer Cap free at the upper coil terminal ends. I then removed the two mounting screws holding the dead Trimmer Cap in place and that’s when things got a bit interesting.

I could not remove the old capacitor from the Coil Assembly. It should have simply lifted right off and away, but was getting hung up on something. It took a few worrisome moments to realize that when the rotator plate broke free from its tension spring, so did its related terminal post that normally sat on the left side of the Trimmer Cap. It had now swung back under the coil-mounting frame and was preventing the Trimmer Cap from lifting out. Once I realized what the problem was and sorted out how to get my left pinkie finger on the errant terminal, I was able to move it back to where it needed to be to lift the old Trimmer Cap free.

After that, the replacement Trimmer Cap went in quite easily and I was able to get the two leads I had installed on it earlier soldered in place quickly. It was then simply a case of reversing the disassembly steps to put all back in place.

The last photo shows the Coil Assembly remounted, the three individual wires resoldered and the Sharp/Flat Switch back in place. This evening I will resolder the Grid Cap Clip and Sleeve on the V1D Grid Cap Lead, tie the sleeve in place to protect the lead from the sharp edges of the V1D Shield Cap and fire the receiver back up to see if there are any noticeable improvements in performance so far.

Hopefully next weekend I can then get the receiver back over to my friend’s workshop where we can finish tweaking it back to life,


David

[David Dunlop]

I have now carefully brushed the loose dirt from the six remaining PINS, cleaned them all with Lemon Oil and given them two light coats of Boiled Linseed Oil, drying 48 hours between each coast and wiping any excess off, one half hour after application to prevent any surface sticky residue buildup.

I then took a sufficient length of new Jute Twine to give them the same double wrap and triple knot binding as the factory original set. there is a 1-1/4 inch loop tied off with a double knot on the originals where an ID Tag would have been fitted. I am leaving that open at the moment while I sort out the details of the tag. There are some bits of equipment hiding here somewhere with these tags on them, but no rush for the moment.

Surprising how close to the originals these cleaned up ones are when finished.

David

[David Dunlop]

The Grid Cap Clip has now been resoldered in place for Valve V1D, the protective sleeve slid back over the connection and a new lace tied over it and lacquered down.

With the receiver top panel back in place, I hooked the receiver up to the Remote Supply and turned it on. BIG Happy Dance The built in Crystal Calibrator came booming in all the way from 1.75 MC to 8.0 MC through Bands 1 and 2. I had to really back the volume off. Prior to this, with AF and RF Gain full on I could barely hear the calibrator signal which completely disappeared around 4.5 MC. The receiver is still not detecting the calibrator signal from 7.0 to 16 MC on Band 3, but a 66% improvement in this area so far is a huge improvement.

In RT Mode and connected to my dipole aerial outside, reception conditions were not great tonight, but I picked up the WWV Time Signal at 5.0 MC with no problem and could just find it drifting in and out at 2.5 MC. Quite pleased with where its at so far and hopefully another session in my friends workshop will have the rest sorted soon enough.

David

[David Dunlop]

So far this week, all I have been doing on the Main Set Receiver each evening has been to turn it on and let it warm up for 10 to 15 minutes. Then I turn on the Crystal Calibrator, let it warm up an equivalent amount of time and then randomly tune to several frequencies on all three Bands of the receiver.

Interestingly, at the start of this process, I had difficulty finding the calibrator signals on Band 3 (7.5 to 16 MC). Now, for some reason, I can track the calibrator all the way through Band 3. Granted, both RF and AF GAIN Controls are maxed out and you really have to pay attention, but they are there now. I cannot help but wonder is after so many years of inactivity, and misalignment, sufficient electrons are now flowing through some of the components once again, they can actually start doing what they were intended to do.

I have also cleaned the 9 Trimmer Capacitors in the RF Coil Assembly and have been dabbing their central tuning cores with alcohol each night in an effort to break up any dirt that might prevent them from turning. The plan for the coming weekend is to realign all the 8 Trimmer Capacitors in the IF Coil Assemblies and then do an alignment of the RF Coil Assembly and see how that affects the performance of the receiver.


David

[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