09-17-2021, 10:03 AM
Last night I got to playing with my Crosley 716 again. I noticed that the tone control did not seem to have any effect. The on/off switch worked on it, but the tone did not vary when you turned the control through its range. Here is the schematic...
[Image: https://64.media.tumblr.com/d449a54cc586...35ee42.jpg]
Part 44Z is supposed to be 100K ohms. It is supposed to have a .1mfd condenser, part 17, in series with it. What I found was a pot, 478K ohms, with an OPEN WIPER ! It is a long shaft pot. I looked at the usual sources on line, and could find short shaft, splined shaft pots, but not what I actually needed. Fortunately I had an old Olympic junk chassis hanging around. I had already scavenged parts from it to restore an Olympic a couple of years ago. It had a 500K audio taper pot with switch. The shaft is longer than I need, but I can cut it. I installed the replacement, and added another condenser in parallel with the .1mfd up to .147mfd. The tone control works OK now. I have to cut the shaft still, and being an audio taper pot, all the adjustment is down at one end, but it works. I guess the original was a linear taper pot. I have one on order, I just hope the shaft is long enough. If not, I'll just leave the one I have in there now.
[Image: https://64.media.tumblr.com/d449a54cc586...35ee42.jpg]
Part 44Z is supposed to be 100K ohms. It is supposed to have a .1mfd condenser, part 17, in series with it. What I found was a pot, 478K ohms, with an OPEN WIPER ! It is a long shaft pot. I looked at the usual sources on line, and could find short shaft, splined shaft pots, but not what I actually needed. Fortunately I had an old Olympic junk chassis hanging around. I had already scavenged parts from it to restore an Olympic a couple of years ago. It had a 500K audio taper pot with switch. The shaft is longer than I need, but I can cut it. I installed the replacement, and added another condenser in parallel with the .1mfd up to .147mfd. The tone control works OK now. I have to cut the shaft still, and being an audio taper pot, all the adjustment is down at one end, but it works. I guess the original was a linear taper pot. I have one on order, I just hope the shaft is long enough. If not, I'll just leave the one I have in there now.
