12Y4 Double Diode
This is the second British Valve used in the 52-Set Receivers and it utilizes the British 5-Pin Socket. It took a little digging to sort out, during which I ran across four different versions of the pin numbering for the socket, including the incorrect drawings in the 52-Set manual schematics.
Only two of these valves are used in the receiver. one is a Noise Limiter and the other serves the AGC circuit. This can come in handy because if both valves get a good rating when tested, but either of these two circuits are not up to par, I can swap the two valves as a first check to see if anything improves.
As far as the settings needed on the Precision Series 612 Tube Tester to test the 12Y4, I am about half way through sorting out that data. The main settings turn out to be the same as needed for the 12H6 tube, so all I have left to do now is sort the correct switches for the five relevant pins. Should have that done tomorrow and then I will test one of my 12Y4's to see how it works out.
If all goes well, I will tabulate the settings for the two valves and try posting a copy here for future reference.
David
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