08-09-2023, 11:01 AM
The PL38 is becoming more and more scarce.
Later production Bush TV22 and TV24 TV receivers employed the then new PL81 as a replacement for the obsolescent PL38.
A believe a service manual supplement was issued describing the modifications needed to use the PL81. A 12,000ohm resistor with a parallel 0.1mfd capacitor were connected between with the screen grid and the connection on the line output transformer.
Very early PL81s were true pentodes but later on the valve acquired beam plates in lieu of the suppressor grid.
Geordie McBoyne.
Later production Bush TV22 and TV24 TV receivers employed the then new PL81 as a replacement for the obsolescent PL38.
A believe a service manual supplement was issued describing the modifications needed to use the PL81. A 12,000ohm resistor with a parallel 0.1mfd capacitor were connected between with the screen grid and the connection on the line output transformer.
Very early PL81s were true pentodes but later on the valve acquired beam plates in lieu of the suppressor grid.
Geordie McBoyne.
