02-27-2021, 11:28 AM
Just my 2 cents worth, but I wonder if some of the Philco printed voltages are a misprint. Concerning the grid voltages on the 27 1st audio and the grid voltages on the 71A outputs, Philco’s posted value of 50V can’t be right. Both 1st audio and output grids are traced back to test point “B”, and that point goes to the center tap of the power transformer which would be the most negative point in the circuit developed across the 187 ohm resistor to chassis ground. Plus consider having 50V on the grid of the 27 while the cathode is grounded doesn’t make sense unless the .01mfd cap #19 is leaky. I’m thinking your -8V makes more sense.
Ron
Ron
Bendix 0626. RCA 8BX5. RCA T64
Philco 41-250. Philco49-500
GE 201. Philco 39-25
Motorola 61X13. Philco 46-42 Crosley 52TQ
Philco 37-116. Philco 70
AK 35 Philco 46-350
Philco 620B. Zenith Transoceanic B-600
Philco 60B. Majestic 50
Philco 52-944. AK 84