09-22-2022, 06:48 PM
good to hear that the radio is "working." apart from the hum. pretty obviously, the buffer cap was bad. all the other waxy paper caps need to go, too. be replaced, that is. they should all have a votage rating printed on them along with the capacitance. this thread has links to various spec sheets with voltage ratings for many philco caps. https://philcoradio.com/phorum/showthread.php?tid=17750
the 2 electrolytic caps numbered 64 also need to be replaced. a 350V rating is plenty. 10 and 20uf are fie in place of 4 and 8. or anything in between. that should eliminate most of the hum, but any cap connected to ground is diverting some unwanted frequency to ground. the negative lead of the 8uf side of cap 64 connects to the case [ground]. because the voltage at the other end is even more positive. by a lot! 200+ volts. the positive ends of the 2 caps are connected to each other.
again, good luck.
the 2 electrolytic caps numbered 64 also need to be replaced. a 350V rating is plenty. 10 and 20uf are fie in place of 4 and 8. or anything in between. that should eliminate most of the hum, but any cap connected to ground is diverting some unwanted frequency to ground. the negative lead of the 8uf side of cap 64 connects to the case [ground]. because the voltage at the other end is even more positive. by a lot! 200+ volts. the positive ends of the 2 caps are connected to each other.
again, good luck.
