06-30-2010, 11:05 PM
I have a 41-280 philco I am working on. I hook it to a varac brought the power up slowly everything look good, after 30 sec. a loud hum started with the volume all the way off. First thoughts Electrolytic cap. bad. Look at the cap. someone had change them out before they used a 30mf 450v and 2 16uf 450v. My riders print show they should have used 8uf 12uf and a 16uf 450v cap, I put what the print show in the radio, power it up slowly hum came back again. So I change out all the old cap. in the radio, power it up again hum still there. This time I change all the tubes out to rule that out, hum still there. Buy this time i was asking myself what am i doing wrong. I than put the larger cap. in the radio, I though the last person new something I didn't, hum still there. I know it is something i am doing with these 3 electrolytic cap. I am attaching 3 pictures, I hope some one can see something i am missing. Please help!!!!!!
thanks
alton
thanks
alton