07-22-2021, 08:10 PM
Well, I am back. After replacing the speaker in its entirety, all power and bypass caps, all out of tolerance resistors, one filter choke and an interstage transformer, got it running pretty well and them ran into a problem with the one filter choke that had checked out good initially. The choke in question (#21) is a Philco part number 3422, 6.5H rated at 150ma and 200DC ohms. I see replacements which are close as both Triad and Hammond make a 6H choke rated at 200 ma and 150 DC ohms.
If I substitute with either of these chokes, I am just a bit short in the Henrys department as well as resistance. Would this be close enough without additional modifications? Do I need to add the 50 Ohms in series or will the replacement choke be a sufficient substitute?
There is a 7H choke from Hammond that is rated at 150ma like the Philco, but its DC resistance is 100 ohms. Would this be a better bet with a 100 ohm power resistor in series?
Any assistance is greatly appreciated. This Model 65 is my first TRF radio, and it has been quite a chore...
If I substitute with either of these chokes, I am just a bit short in the Henrys department as well as resistance. Would this be close enough without additional modifications? Do I need to add the 50 Ohms in series or will the replacement choke be a sufficient substitute?
There is a 7H choke from Hammond that is rated at 150ma like the Philco, but its DC resistance is 100 ohms. Would this be a better bet with a 100 ohm power resistor in series?
Any assistance is greatly appreciated. This Model 65 is my first TRF radio, and it has been quite a chore...
Richard
