Wireless Set No. 52 Canadian - Project

[David Dunlop]

Back with the Main Supply Unit.

A few days go I was able to install an NOS 0Z4A in the Vibrator Supply section and decided to reinstall the complete Supply Unit back into the Carrier, reconnect everything and fire it up. I was curious to see if that might solve the chronic missing 2 Volts DC from the LT Circuit to the Set.

It did not. At that point I was going to shut everything down but decided to see if the HT 1 Circuit, 150 Volts DC driving the Receiver from the Vibrator Supply had improved. The Meter showed no volts at all. That was a surprise. I had not reinstalled the three mounting bolts for the Supply Unit so decided to do so and call the work quits until the electronic parts I had ordered arrived. I started to reinstall the left side bolt between the receiver nd Supply Un it mounts and the SENDER HEATERS indicator lamp started flickering, which was odd because that circuit was not turned on. Then I noticed this lamp was flickering in. an alternating pattern with the indicator lamp on the Receiver and the flickering was in direct response to me handling the mounting bolt and nut. It appeared to be a grounding issue but I was tired and just shut everything down and pulled the Supply Unit out of the Carrier again, while notin g what an absolute struggle it is to get this small, but VERY heavy component, in and out of its compartment.

I went upstairs and bounced the issue off a friend down East familiar with the 52-Set and went to bed. A rapid response from my friend confirmed the issue was a bad ground, not an uncommon issue with the 52-Set late in its Canadian Army Service. The culprit is the heavy thick coats of Red Oxide primer and NATO Green paint these sets received in the 1960’s all too often including the interiors of the Carriers No. 4 and the Remote Receiver Case. There is no hard wired grounding line between any of the connecters for the Receiver, Supply Unit and Sender in the Carriers No. 4 The Ground between these components comes solely from the the bottoms of the component chassis rails sliding on the Satin Nickel plated floor of the carriers No. 4 and a pair of similarly plated spring clips mounted on the top rear face of each compartment pressing down on the top chassis rail of each component as it engages its connectors on the back wall.

So today was spent getting rid of that ugly paint on the two bottom strips of the Supply Unit compartment and the two spring clips. Be interesting to see how the Supply Unit performs once it is back in place with a ground connection working as the designers of the Set had intended 81 years ago. I added a couple of photos of what the floor of the Supply Unit Compartment looks like now, along with the two spring clips.


David