[David Dunlop]

When I was working on the Sender, I had taken the testing as far as I could, which was basically up to where a working Supply Unit was needed to feed the Sender for any further testing.

I have gone as far as I can now for the moment with testing the Supply Unit. I completed a set of Resistance Tests this morning. All results were on the mark but one, where I got a 74 Ohm return where there should have been 150 Ohms. I also completed all but one of the Operator’s Maintenance Tests for the Supply Unit. These could be run with the Supply Unit either in, or removed from the Carriers No. 4 and all tests gave positive results. The last test of this group is to turn on the Sender Heaters to let the Sender warm up and then flip the Send/Receive Toggle Switch to ‘SEND’. One should hear the relays in the Sender kick in to isolate the Receiver and both Dynamotors should kick in. A HT1 Voltage reading for the Sender of about 300 Volts DC should also show on the sets meter.

I have a much greater appreciation of why a pair of jumper cables for the 8-Pin Connectors between the Supply Unit and Sender are such a great idea. You can do these tests outside of the Carriers No. 4 with the internals of both the Supply Unit and Sender fully visible. Way too nerve wracking when everything is out of sight.

So back the Supply Unit went into the Carriers No. 4 and everything got reconnected. I turned on the CPP-2 and gave it a 5 minute warmup, and then turned the set on. As soon as the Receiver came on line with the WWV Signal at 10.0 MC, I turned on the Sender Heaters and let the set warm up another 5 minutes. With everything on the Sender roughly tuned into 10.0 MC as well, I then turned on the NET circuit in the Sender. The Dynamotors kicked in nice and quiet, but the HT1 reading for the Sender was only 110 Volts DC, not anywhere near the expected 300 Volt range.

Last critical test was to turn off the NET Switch and flip the last switch on the Supply Unit from RECEIVE to SEND. The isolation relays kicked in perfectly and both Dynamotors wound up, but they were under a very heavy load and very growly. The Sender HT1 Voltage was still no higher than the 110 Volts DC from the previous test so I switched back to RECEIVE right away. So something in the Sender does not want to play well with the other components. Good to know.

Next tests will be to go back to the NET Test and take meter readings for all the Sender valves to see how they compare to the specifications in the manual.


David