11-27-2016, 12:49 PM
Well, things have been going well when, while going thru the alignment, one of the filter chokes opened up. It is Philco part number 32-7491. It is shown on the schematic as having a DC resistance of 400 ohms. I can't find what the impedance or current rating is supposed to be. Does anyone have any information for a suitable replacement?
I am not really sure why it opened up all of a sudden, as the radio has been playing very well for weeks. This choke does supply the B+ for the IF stages and the discriminator circuits. Is there anything that I may have done in the alignment process which could have caused the choke to open up? I can't think of anything. Nothing appeared abnormal, no mistaken shorts. (I was using an insulated tuning stick.) Maybe the choke was just on its last legs to begin with.
I am not really sure why it opened up all of a sudden, as the radio has been playing very well for weeks. This choke does supply the B+ for the IF stages and the discriminator circuits. Is there anything that I may have done in the alignment process which could have caused the choke to open up? I can't think of anything. Nothing appeared abnormal, no mistaken shorts. (I was using an insulated tuning stick.) Maybe the choke was just on its last legs to begin with.
Chris H
N9WHH
