Prototype set is here

[Penthode]

I attached a Hazeltine article on Friday but upon looking for it this evening it is gone!? Don't know what happened but I will see if I can repost it tomorrow.

In the Hazeltine diagram, R-Y phase inversion is accomplished by simply using a field rate multivibrator (12AT7) locked to a field recognizer detector (another 12AT7) to the correct field. The CPA transformer secondary is center tapped so that either end (180 degrees apart) is selected field by field to supply R-Y or -(R-Y) as required.

Note that the Hazeltine implementation at that time did not include a crystal controlled subcarrier oscillator.

Did anyone of you have a chance to see the article/diagram I posted on Friday while it was there?