Wireless Set No. 52 Canadian - Project

[David Dunlop]

Nearly a month ago, I had noted the meter readings on the Main Set Receiver were running low at 10 Volts DC and 130 Volts HT.

Since then, I have been running the set several nights a week for 15 to 20 minutes. Basically until it has warmed up and stabilized. During this process, the meter reading for the HT has settled in at a steady 125 Volts.

While killing some time this evening, I was reading through a few sections of the Operators Manual while the set was idling and noticed the comment in the Maintenance Section about checking the Meter from time to time to ensure it was correctly reading Zero when the Receiver was shut off.

I could remember checking the Zero Setting of the Meter on the Remote Receiver when I went through it, but could find no reference in my notes to doing so for the Main Set Receiver. The only references I had were to the fact the meters in both receivers were from two different makers. So I switched the set off. Sure enough! The meter needle pinned itself well below the Zero Mark. A quick adjustment of the Zero Set Screw at the bottom of the meter brought the needle spot on the the Zero Mark centre and I fired the set back up. I am now getting a steady 11 Volts LT and 135 Volts HT. A closer look at the resisters in the Meter Circuits will still be needed as that is the next likely point of issue. Some or all of these resisters may have finally gone off normal specifications.

David

[David Dunlop]

Back in Post #570, I had noted the LEADS, Aerial, 25-3/4 inch was temporarily installed on the 52-Set. This was basically to get the Leads in its final, correct position while the paint, lettering and clear coat were still relatively soft and uncured. I wanted that large lazy curve on the Receiver end of the Leads to get established so the Leads will be comfortable in that position down the road. Hopefully it will take on the nice aged look of the one Bruce has in his possession.

Since this was a temporary install (I still have the Receiver work to finish and have not started work on the Supply Unit) I had not bothered connecting the Sender end of the Leads to its terminal. I got to that point yesterday to find the pin terminal on that end of the Leads would not seat properly in the Sender AE Terminal Post. A closer look showed that when I was doing the final tightening of the AE Terminal when aligning the pin slot in it with the stem of the last Eye Screw, the AE Terminal must have shifted about 5 degrees clockwise. Just enough to jamb the pin from sliding all the way into the slot.

So out of the Carriers No. 4 the Sender came once again yesterday afternoon so I could realign the AE Terminal once more.

Getting the Sender in and out of the Carriers No. 4 is an interesting exercise. With the four mounting bolts out of the way, the two Handles at the lower centre of the Sender are definitely down where most of the mass of the Sender is located, but most of the resistance is in the upper left corner of the Carriers No. 4, where the two, 8-pin Connectors are located.

The Sender will slide out it seems, just until the four angle brackets are free of the Carrier. Then, the pulling force seems to have an upward element to it rather than straight out the front of the Carriers. This loads the contacting surfaces of the two 8-Pin Connector assemblies and they start to bind. Not a great thing for 75+ year old Bakelite. So to counteract that load, I now open the Blower Door so I can grip under the upper Sender Chassis lip with the fingers of my left hand and my thumb on the upper face of the Carrier, gripping that part of the Sender towards me while trying to put straight out as much as possible with the right hand Handle down low, with my Right Hand. The Sender pops out quite easily doing that.

To go back in, I find the Sender will slide relatively smoothly up until the two 8-Pin Connectors make contact with each other when significant resistance is met. At that point, I switch from pushing with the two Handles to placing Left Thumb centre top of the Blower Door and fingers down the left side of the front panel, above and below the Mounting Bracket. Right thumb on the right side Mounting Bracket. Applying pressure at those two points gets the two 8-Pin Connectors sliding into each other smoothly and alternating between those positions and the two lower Handles gets the Sender snugged home safely.

CMC did not expect the 52-Set Operators to have to pull the individual components out of the Carriers No. 4 at all. Unlike the classic 19-Set, all Operator valve servicing could be done via various removable panels, or the Sender Blower Door. As a result, there is no real information supplied in the Operator’s Manual regarding technique fro removal and installation. I thought this might help somebody sort it out sooner or later.

With the AE Terminal on the Sender now correctly readjusted, the Leads slides into place just nicely.


David

[David Dunlop]

A little bit of a spinoff from my last Post.

While temporarily having the Leads, Aerial 25-3/4 inch installed, I am not yet able to feed it through the Eye Screw located at the top of the front panel of the Supply Unit, because this particular Eye Screw has had the eye loop crushed in on itself.

If you look at the upper panel edge in this photo, you can see a set of four angled gouges in it, running from the right side to directly over the Eye Screw located at the upper right corner of the Sender Heaters decal.

When Jacques and I got our first close looks at the Supply Unit, we thought somebody had used a heavy screw driver in the upper panel edge to try and force the Supply Unit out of the Carriers No. 4 at some point in time. A close look at the inner face of the Carrier No. 4 in those four locations shows absolutely no damage at all.

So my current theory is that at some point in time, the Supply Unit had been removed from the Carriers No. 4 and was sitting on its own somewhere when a pair of Idle Hands came along with nothing better to do and decided to give the top edge of the panel several whacks with a ball peen hammer, or chunk of heavy bar iron. The one blow directly above the Eye Screw caught it and bent the eye closed.

Now noted for future repair.

David

[Chris Suslowicz]

Originally Posted by David Dunlop

A little bit of a spinoff from my last Post.

While temporarily having the Leads, Aerial 25-3/4 inch installed, I am not yet able to feed it through the Eye Screw located at the top of the front panel of the Supply Unit, because this particular Eye Screw has had the eye loop crushed in on itself.

If you look at the upper panel edge in this photo, you can see a set of four angled gouges in it, running from the right side to directly over the Eye Screw located at the upper right corner of the Sender Heaters decal.

When Jacques and I got our first close looks at the Supply Unit, we thought somebody had used a heavy screw driver in the upper panel edge to try and force the Supply Unit out of the Carriers No. 4 at some point in time. A close look at the inner face of the Carrier No. 4 in those four locations shows absolutely no damage at all.

So my current theory is that at some point in time, the Supply Unit had been removed from the Carriers No. 4 and was sitting on its own somewhere when a pair of Idle Hands came along with nothing better to do and decided to give the top edge of the panel several whacks with a ball peen hammer, or chunk of heavy bar iron. The one blow directly above the Eye Screw caught it and bent the eye closed.

Now noted for future repair.

David

It may have been in a different carrier when Mr Hamfisted attempted to pry it out (or force it back in, not realising that if you remove all the units from the carrier you have to remove the interconnection bar because the connectors definitely won't line up and fit it after everything is back in position). There may be another rack out there with matching damage,

Chris.

[David Dunlop]

Hi Chris.

That is another good possibility, actually, though the most likely place for Carriers to have been switched up between a number of 52-Sets would have been at No. 202 Workshop where all the major overhauls took place. That would suggest Mr Hamfist would have been in the military, perhaps a wireless operator, and that couldn’t possibly happen, could it?

Said Workshop may not have had a high priority for returning exactly the same equipment to a unit that submitted it for overhaul, as far as I know. As long as a duff set came in and a fully working one was returned, that might have been acceptable. Again, I do not know what the actual service procedures would have been.

I do know issues did occur where upper panels on Receivers were replaced on incorrect lower chassis assemblies, which caused a level of concern at 202 Workshop. That meant the Modification Records stored in their holder on the lower chassis no longer matched the serial number on the Data Plate mounted on the removable upper panel. Several Receivers are known to have survived with a mod moving the Data Plate to the lower chassis, where the left side Handle was originally located, and that Handle being moved over near the Meter. The work on all those receivers is identical, suggesting some form of standard was being followed.

The damage on this Supply Unit panel and Eye Screw definitely appears repairable at the moment, so in that regard, things are still on track. And besides, what fun is a project if there are no mysteries involved!

David

[David Dunlop]

An interesting day working on the Main Set Receiver yesterday. Some mysteries solved. Some new ones added to the pot.

The first thing that came to light, literally, was the discovery of a cracked outer terminal wafer on the Wave Change (Band) Switch, S6A, located on the upper right side of the receiver chassis. I had never seen this before, and initially thought I had been the cause as this switch sits right where ones hand instinctively goes to grasp the upper side of the chassis assembly when picking it up. The only reason I noticed it was because the work lamp on that side of my bench was on when I put the receiver down and the light created a shadow on the wafer that caught my eye. A close inspection, however, revealed the inner core of the fracture was not fresh, but had discoloured over a period of time.

In the attached photo, the crack runs through the empty 5th terminal position, between the two occupied terminals at the 5:00 position on the wafer.

Studying the wafer, I then noticed the none factory soldering point on the top right most terminal, where a new, plastic covered lead was soldered into the bottom side of the terminal, rather than onto the actual terminal itself that faces inward on the other side. This new lead runs up to the S5A Relay up behind the 8-Pin Connector on the back of the receiver. My thinking is that a repair was done at some point where the two retaining screws for the wafer were removed in order to pull the wafer forward to access the necessary terminal to effect the repair, There are several heavy gauge, solid copper wires soldered to this wafer and they likely resisted moving forward at the expense of cracking the wafer. The rotating contact plate and terminals on this outer wafer are still interacting correctly, so the old lead was likely cut away, the wafer carefully reinstalled and the new lead soldered to the bottom of its terminal.

That was the most exciting part of the days work, but I now know to take extra care when I dismantle this S6A switch from my Spare Parts Receiver down the road.

David

[David Dunlop]

The game plan with the Main Set Receiver yesterday was to first look at the LT and HT Meter Readings with the receiver running off the ZE-11 Remote Supply. The last time I had done this, the meter had not been properly set to its zero mark.

Before connecting up the ZE-11, however, I took the time to check the values of all the relevant metering resisters on the receiver. They all spec’d out in the same range of values as the ones in the Remote Receiver that works perfectly, the ones in the Spare Parts Receiver and the supply of NOS ones I have on hand, some of which I had to use to replace ones in the Remote Receiver that had gone ‘full open’. So all that looked good.

Since the ZE-11 would be operating in AC Mode, I set the meter on HT and hooked up the ZE-11. In AC Mode, the Remote Supply 12 Volt output is in AC Current and cannot be detected by the LT meter circuits.

When I turned the ZE-11 on, the HT reading went up just above 180 Volts for a fraction of a second and then dropped steadily to just a whisker above the 150 Volts mark, just as the white noise audio output arrived on the loudspeaker. Under no load, the output of the Remote Supply is about 30 volts or more above required specifications for the receiver. To test the output properly in these conditions, it is necessary to connect an appropriately sized resister across the 150 Volt output terminals of the ZE-11 as a load and take the reading from there. The meter was spot on with its information. With a fully discharged electrical system in the receiver, there is no load on the Remote Supply for a few milliseconds until capacitors etc. start charging up. As the circuits charge up, the load increases and the recorded voltage drops to its normal operating point. This told me the meter was in good working order. One big step forward.

While the Main Set Receiver was out of the Carriers No. 4, and to give the receiver a chance to warm up and stabilize, I let it run and turned my attention to the Supply Unit in the Carriers No. 4. I powered up my CPP-2 and hooked up a lead to the +12 Volt terminal in the Carriers No. 4 for the receiver. Then I realized I needed a second lead to ground on the Carriers No. 4 to complete the circuit. More on that later. I reinstalled a bolt into one of the receiver mounting holes and connected the second lead to it, and hooked up my multimeter.

When I turned the switch on at the Supply Unit, I got a perfectly steady 12.3 Volts DC reading that matched the output of the CPP-2 perfectly. I then shut the Supply Unit off and switched my leads to the +150 Volt receiver terminal in the Carriers No. 4. Since the vibrator supply portion of the Supply Unit, which feds the receiver, is a very similar design to the ZE-11 Remote Supply, I expected to get a high reading here. Something in the +180 Volt range, since there would be no load on the output for it to work with. Sure enough, when the Supply Unit was turned back on, the multimeter swung back and forth a few volts either side of the 180 Volt value. This was all good information.

I know knew the Main Set Receiver was reading correct voltages and behaved in a similar manner, to a point, as the Remote Receiver when running on the ZE-11 Remote Supply. But there were LT and HT voltage drop offs when the receiver was operating in the Carriers No. 4. I returned to the idling receiver and switched on the Calibrator. The meter was now reading about two whiskers north of the 150 Volt mark and it dipped just to the 150 Volt mark but as the Calibrator warmed up, the needle returned to its original slightly high position. Equally good news.

I went back to the Carriers No; 4, and reset the multimeter to the +12 Volt terminal for the receiver and switched the Supply Unit back on. 12.3 Volts steady. I then flipped the switch on the Supply Unit for the Sender Heaters. The 12 Volt reading dropped right to 10 Volts and sat there. I powered everything off and switched over to the +150 Volt terminal again. Turned the Supply Unit back on and got the reading bouncing around the 180 Volt mark once more. Then I turned the Sender Heaters back on and this reading suddenly dove down to the 110 to 130 Volt range and bounced around there. This leads me to suspect the Supply Unit will need a close look when its time comes.


David