I was wondering if the model 40-180's have a common issue with tone control pots? I just got done recapping mine and the tone control doesn't seem to work. I can't tell a difference in bass when turning from min to max. I followed the schematic closely but can't seem to get it to work. When looking at the schematic it is part number 51 on the parts list. What I don't understand is what the resistance means on each side of center tap. Is the pot a 6 MEG? It says 6 MEG on one side of the center tap and 400K on the other. There are no other resistors attatched to the tone control, just a .01mF on one terminal and .003mF on the other with the center tap going to ground. Does this mean it is a 6 MEG at max and 400K at min or vis versa? I have also tried switching the .003mF and the .01mF to the opposite terminals of the pot but that didn't change the way it sounded at all. It is getting frustrating because the tone control worked before I recapped it. Other than the tone issue the radio sounds incredible! Any thoughts?
(This post was last modified: 07-12-2015, 11:03 PM by sdradioman.)
I didn't have an issue with my tone control on my 40-180 post recap. I have a pretty clear shot of it pre-recap I can post here or PM you with later tonight at home if that will help you.
(07-13-2015, 08:58 PM)sdradioman Wrote: Yea, that would be great. You can just put the picture on this post since I don't know how to PM. Thanks for the help!
PM is Private Message. It's like a post here on the forum, but only you and I can see it. So not everyone has to see an obnoxiously large picture if I were to post the fully uncropped and unresized picture. But here is a slightly cropped and slightly shrunken picture.
Yep, that's how it was when I started and that was how I recapped it but the tone doesn't change. I think I may have a bad pot then. I have a spare that I will swop out and see it that changes anything. Thanks for the picture!
So it ended up being the tone control pot. I disassembled it and inspected. I don't know what happened but it must have happened when I was cleaning it. The entire carbon pad was for lack of a better word, desintigrated. I nabbed one out of a 40-185 that I had and it works perfectly!
