Wireless Set No. 52 Canadian - Project

[David Dunlop]

Rod.

I was about 4 years old when I first introduced myself to the exciting world of electricity.

My parents had given me a Punkinhead desk lamp for my room, which always had to be on when I went to bed. For some long lost reason one day, I decided I wanted to cut the plug off the end of the cord. I knew enough that the cord would be a tough cut but I was sure Mum's prized Sheffield Steel Dress Making Shears would be up to the task. I also figured I would need both hands on the shears to be successful, so leaving the plug in the wall socket seemed a logical thing to free up both hands. I had also thought through that since I was making sure the lamp was turned off, no electricity could possibly be involved in the activity.

The flash and the bang were spectacular! A funny tingling raced up my arms and the shears went flying to the back of the room and a scorched metal smell lingered in the air. When I retrieved Mum's shears, a neat arc had been burned out of one of the blades, the same diameter as one of the cord conductors. Needless to say, putting them back where they belonged and playing dumb and stupid didn't work.

Cheers,

David

PS: I am betting that lamp would be worth a fortune today in original condition.

[David Dunlop]

I found this 7mm rubber cased HT ignition cable on line and ordered 10 feet of it to fabricate one of these LEADS. It has the correct stranded copper core and a nice high heat rating. The silver ID labelling along the cable also comes off nicely with a solvent I have, so a little progress on that part of the project now.

David

[David Dunlop]

An interesting development over the weekend.

I completed the required Voltage and Resistance tests on the Remote Receiver, which have provided some interesting information. I also finally pulled all the valves from the Remote Receiver to run them through the tester.

You may recall that at the time I acquired the three 52-Set receivers, I had no means of testing the British based ARP-3 and 12Y4G valves, so simply cleaned and visually inspected them all, cleaned the sockets and put each valve back where it came from.

So now the ones in the Remote Receiver all came out again and each was given an ID tag. Of the eight ARP-3’s in the receiver, the V1C (Mixer) was totally dead and another, the V1G ( 1st AF Amp), was so weak as to be useless, so both were replaced by good ones from my parts receiver.

The real surprise was the two 12Y4G’s on board. Both V2A (Detector/AVC) and V2B (Noise Limiter) were completely dead on both sides internally. Not even the slightest glow in the dark from either after 20 minutes of receiver warm up. When I pulled the easily accessed 12Y4G from the parts receiver, it too was completely dead on both sides.

That seems like an extremely high failure rate for a valve and it has now got me wondering what kind of a reliability record these 12Y4G’s had in service use.

David

[Bob Carriere]

Lots of the work you are doing is way over my head....but if those valves have been fried....so many of them...... could there be something else that "blew" them out......and could you be risking the new tubes you are planning to put in? ............ dried up capacitor...... any physical damage that could cause a ground....... Just curious!!!!

Too cheap to buy a proper static bracelet when working on my computer to eliminate any static charge I might build up................. so I wrapped a light piece of copper wire to an overhead water copper pipe in the basement computer room.......with the other end loosely tied to my left wrist..... until some one reminded me that if I accidentally touched a 110 v wire......I might just fry myself with a "dead ground" around my wrist........ I do have a proper voltage limiting bracelet now.......

Cheers

[David Dunlop]

Hi Bob.

I wondered a bit at first also, but then realized I had three dead valves between two different receivers. I did pull the second 12Y4 from the parts receiver, checked it and tried it in the Remote Receiver. It lit up and behaved beautifully!

On the down side, however, when I found the supply of NOS valves I bought a couple of years back, only one 12Y4 was in the bunch. It is now also in the Remote Receiver and running just fine. Quite a difference in performance in the Remote Receiver now, but still a ways to go with tweaking.

One interesting possibility has come up from some experts down East and in the UK. These valves go through a lot of heat up and cool down cycles when in use over time. The constant expansion and contraction cycles can eventually pop the soldered leads inside the valve base pins loose from the inside of the pins, causing the circuits within the valve to go into an open state. It has been suggested I try heating the pins and reapplying a dab of solder to the pin tips. This can often restore the valves. If not, and the two remaining valves in the Main Set Receiver are dead...not good. There be no spares at the moment.

Cheers,

David

[David Dunlop]

Thought I would show the steps I used to correctly align the TERMINALS, Aerial, No. C1 on my Remote Receiver, if anyone needs to do the same. It is also a good reference for me down the road, if I should forget how I did it when the Mains Set Receiver is due for a tweak.

The first photo is one I thought I would add because it shows the correct placement of the upper receiver panel, in relation to the two aerial terminals. Note the relatively even spacing of the upper panel around the two terminals. This upper panel has the ability to float about when being locked in place, which can allow the edges of the panel to come in contact with the sides of the lower aerial terminal socket. This should be avoided as it can result in the signals being received getting pulled to ground, which will mess with your reception.

In the second photo, I have inserted a 1/8-inch drill bit into the slot in the TERMINALS, Aerial to highlight the incorrect 12 - 6 position it is currently in. The tricky bit here is that in order to correctly align the orientation of the TERMINALS, Aerial, the Upper Panel assembly of the receiver has to be removed, and that is where the easiest reference mark for alignment resides. So to get around that, as shown in the third photo, I attached a tooth pick to the right side of the chassis at the point where the correct 4 o’clock position for the TERMINALS, Aerial should be. Then it is a simple process of removing the Gas Gap tube from its clips and reaching in with a quarter drive socket and slotted screwdriver head to loosen the TERMINALS, Aerial set screw enough to rotate the fitting to the correct orientation. There is no way around this process. It will require careful hands, a good sense of touch and patience, but can be done. Once everything is correctly lined up and secured, do not forget to clip the Gas Gap Tube back into its clips.

The last photo shows the TERMINALS, Aerial, No. C1 finally back into its correct 10 - 4 position. One more part of the puzzle done.

David

[David Dunlop]

I have been taking a bit of a break from receiver work today and taking a closer look at the Carriers No. 4 assembly to better sort out the work it will need down the road.

While Jacques Fortin had been keeping watch over the set for me prior to shipping it West, he had noticed all three components took a bit of grunt work to get in and out of the Carriers. A large part of this was attributable to the shear weight of at least the Supply Unit and Sender bearing down on the painted interior surfaces of the bottom of the compartments. Any dirt on the bottom chassis rails of the components really dug into the paint and there was no sense of 'slide' whatsoever. My short term thought on this is to strip the paint chemically from the bottom of the compartments to hopefully reveal the original factory satin nickel plating.

The other point of concern ws the snug fit of the Receiver into its compartment along the sides. While taking a closer look at this issue today, I discovered the left side panel of the receiver compartment bulges into the compartment right at the point where the left side mounting screw locates. I at first thought the problem was an overtightened screw at some point in time that drew the side panel in, but a close look suggests this is unlikely. The mounting screw passes through the side panel skin and starts threading into the steel reinforcing bar located around the outer edges of the panel. It then continues into the front guide bar assembly for the retracting carry handle which takes up all of the load of the screw. Looks like it should be an easy fix, however. Next time the receiver is out of the Carriers, I should be able to tap the bulge back flat to prevent the panel from binding on the receiver mounting bracket and upper panel assembly.

David