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  #241  
Old 18-02-20, 17:10
David Dunlop David Dunlop is offline
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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
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  #242  
Old 19-02-20, 04:18
Bob Carriere Bob Carriere is offline
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Location: Hammond, Ontario
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Default Following your postings with great interest......

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
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Bob Carriere....B.T.B
C15a Cab 11
Hammond, Ontario
Canada
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  #243  
Old 19-02-20, 05:20
David Dunlop David Dunlop is offline
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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
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  #244  
Old 21-02-20, 19:50
David Dunlop David Dunlop is offline
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Default TERMINAS, Aerial, No. C1 ZA/CAN 4716

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
Attached Thumbnails
TERMINALS, Aerial, No. C1  ZA:CAN 4716 f.JPG   TERMINALS, Aerial, No. C1  ZA:CAN 4716 g.JPG   TERMINALS, Aerial, No. C1  ZA:CAN 4716 h.JPG   TERMINALS, Aerial, No. C1  ZA:CAN 4716 i.JPG  
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  #245  
Old 24-02-20, 00:33
David Dunlop David Dunlop is offline
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Default WS No, 52 Carriers No. 4

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
Attached Thumbnails
WS No. 52 Carriers No. 4 5.JPG  
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  #246  
Old 24-02-20, 01:05
David Dunlop David Dunlop is offline
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Default BLOWERS, Electric, 4-Blade, No. C1 ZA/CAN 4411

I am not sure how large of a sub title these individual posts can handle, so I will start by providing the full description ID of this part as follows:

BLOWERS, Electric, 4-Blade, 3-inch, 12 V, 1.2 Amp No. C1 ZA/CAN 4411

One each of these are located in the upper panels of the Supply Unit and Sender of the Wireless Set No. 52. They are thermistor controlled, only coming on when the internal compartment temperature rises to a preset point, either from excess ambient air temperature, or excessive dynamotor operation. I suspect they are set up as exhaust fans, but that has yet to be confirmed.

While I was in the mood to explore the fan in the Sender more closely, I hauled out the trusty warm soap water and toothbrush to clean off the grime on part of the rear of the fan assembly. I deferred use of any chemicals as the two horizontal electrical components seen lashed to the rear of the fan motor looked very much like wax coated capacitors. I was 50% correct. The forward one was indeed a .1 microfarad 500 Volt cap, C3AF in the schematics. The rear cylinder, on the other hand, turned out to be the small R.F. Choke (L30B) to suppress noise from the fan motor and it was tucked neatly into a small plastic tube.

While not yet a comprehensive cleaning, it did confirm a pair of CMC inspection stamps on the back of the fan door assembly, and another pair on the rear face of the lower phenolic resin board on the lower half of the motor, The name “REDMOND” also showed up stamped on the back of the motor case, just below the rear bearing cap assembly.

David
Attached Thumbnails
WS No. 52 BLOWERS, Electric 1.JPG   WS No. 52 BLOWERS, Electric 2.JPG  
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  #247  
Old 24-02-20, 18:33
David Dunlop David Dunlop is offline
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Default BLOWERS, Electric, 4-Blade, No. C1 ZA/CAN 4411

I connected a 2 Amp 12 Volt supply to the Blower in the Sender this morning and both fans sprang to life nicely. Very quiet operation and the amount of air they can pull out of the Supply Unit and Sender would be very effective, if needed.

They showed no wind down at all when the power was cut off, which could be by design, or more possible, they have seen little or no use over 75 years so are essentially brand new with no lubrication for at least 50 years. Time to see what the publications say about fan maintenance.

David
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