09-14-2015, 10:33 AM
In working on the 41-285 chassis I have in another thread, I have been doing some comparisons of chassis layouts between my 41-280 and 41-285. I has finally dawned on me that somewhere along the line, someone clipped the CT lead on the output transformer. Could that be the source of the hum I get on this 41-280 set? He clipped it off right at the outer insulating paper cover. Do you think it might be possible for me to make a small cut in the paper at that point and solder a new lead in place? The schematic shows the output transformer CT connecting to the grid of one of the 41 tubes and to the junction of R28 and the electrolytic C27A (16uf).
Looking at a close up of the OT, I can see four leads coming from it. Two go to the plates of the 41s. One goes to the terminal strip beside the OT where it seems to connect to a yellow cloth-covered wire that goes to the speaker. The fourth goes toward the bottom 41, but I will have to look at it when I get home to trace it (and the yellow wire to the speaker). Shouldn't the OT have five leads coming off of it?
Looking at a close up of the OT, I can see four leads coming from it. Two go to the plates of the 41s. One goes to the terminal strip beside the OT where it seems to connect to a yellow cloth-covered wire that goes to the speaker. The fourth goes toward the bottom 41, but I will have to look at it when I get home to trace it (and the yellow wire to the speaker). Shouldn't the OT have five leads coming off of it?
Charlie in San Antonio
