52-Set Supply Unit Vibrator Supply
Work on the Vibrator Supply section of the 52-Set Supply Unit is slowly moving forward.
I pulled it from the Supply Unit for some bench testing and while it was out of the Supply Unit, I decided to turn the set on to see what sort of reading I got from the meter on the Receiver, with regards to the 12 Volt LT input. This should be a straight pass through from the batteries, but with the Vibrator Supply in place, this value has always come up about 2 Volts DC too low. My CPP 2 Supply was providing 12.75 Volts DC to the Set. When I turned the Receiver on, the meter on the Receiver showed exactly 12.75 Volts DC coming in. Good to know, so I got curious and reinstalled the Vibrator Supply, and turned the set back on to see what happened. The meter was back down at 10.0 Volts input. What was different this time, however, was when I checked the HT Input to the Receiver on its meter, zero volts were coming in. Prior to this, it had always been 147 Volts DC from the expected 150 Volts. So onto the bench for a further look.
I am rusty with the electronics analysis these days, so I do a lot of triple checking and thinking, but have been able to determine the Vibrator and 0Z4A are both in good working order. The T7A transformer is providing correct input voltages to the plates on the 0Z4A to fire it up and I have continuity from the start to finish on the 150 Volt circuit. But one or more unhappy components exist in the circuit that will need ionvestigating in more detail.
This Vibrator Supply is a compact little sucker as noted in the two photos, so a very careful unbolting and moving of components will be needed to access suitable test points as the work progresses.
David
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