Wireless Set No. 52 Canadian - Project

[David Dunlop]

Finally got back to some thinking about the potential short in my Main Set Receiver Connector Socket this past week. In particular, the fact that I had noticed when connecting the Remote Supply Connector Plug to the socket, the retaining screw did not seem to run home as far as it did when I connected this cable to my backup receiver. That in turn got me wondering it this screw might be jamming on some loose bits inside and perhaps be part of the short problem.

Add to that, I was curious if it might be possible to isolate if the short was in the 12 Volt LT circuit, or the 150 Volt HT circuit. So I dug out my trusty old 2 Amp 12 Volt DC Trickle Battery Charger to jumper onto the 12 Volt circuit and see what happens.

I first tested the charger output. It was producing 11.78 Volts DC, along with 6.69 Volts of AC. I first jumpered it to the +12Volt terminal on the backup receiver socket and negative to chassis ground. The panel indicator lamp on the backup receiver lit straight away and I got a reading on the meter of 8 Volts DC LT. Turned on the calibrater and its indicator lamp lit and the meter reading dropped to 7 Volts and held. I waited a minute, switched off the calibrator and the meter went back up to 8 Volts and held.

I then switched the charger over to the Remote Receiver and jumpered it up in the same manner. The results were virtually identical to the backup receiver.

I am pleased with those results. Next, I am basically going to repeat this test with the Remote Supply, using jumper cables for both the 12 Volt LT and 150 Volt HT circuits. Basically bypassing the physical connection of the Remote Supply Connector Cable to the receivers. Hopefully that will provide some further useful information.

And while I was mucking about with the Connector Socket on the back of the backup receiver, I noticed the long paper label that runs across the middle of it with the Terminal IDs printed on it was missing. A closer look in that area revealed a cast oval mark with 'CMC' in the middle of it, about one third of the way in from one end. Photo attached. Pleased to finally find one of these marks and hope to find more as the project progresses.

David