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
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