08-01-2023, 10:54 PM
I don't know why people on Facebook, etc. have to act like jerks. A restorer tries to make the set as original as possible. There are several ways to do things. Don't let anyone criticize your good work!
Check all of the resistors involving the grid and screen circuits. Instead of using a phase invertor or a cathodyne phase invertor, Philco uses a novel method of obtaining the inverted phase for the 2nd 41 in the push pull output. It is pulled from that screen resistor. Check the 41s for shorts and matching. Check the output transformer also. If an output transformer is open or disconnected and the radio is fired up, the screen current goes off the charts. You can actually see the screen grid glow, almost white hot. Had this happen to me. Almost lost a cool Philco globe shaped 42 from an open output transformer.
Max screen current for a 42 is 6.5mA or 0.0065A. If the voltage drop across the resistor is low, then the dissipation is also low.
Good luck with the restoration. When you got the output stage right, this radio should sound great.
Check all of the resistors involving the grid and screen circuits. Instead of using a phase invertor or a cathodyne phase invertor, Philco uses a novel method of obtaining the inverted phase for the 2nd 41 in the push pull output. It is pulled from that screen resistor. Check the 41s for shorts and matching. Check the output transformer also. If an output transformer is open or disconnected and the radio is fired up, the screen current goes off the charts. You can actually see the screen grid glow, almost white hot. Had this happen to me. Almost lost a cool Philco globe shaped 42 from an open output transformer.
Max screen current for a 42 is 6.5mA or 0.0065A. If the voltage drop across the resistor is low, then the dissipation is also low.
Good luck with the restoration. When you got the output stage right, this radio should sound great.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
