[LarryFS]

My 650X has a four position tone control.  Problem is that I can't detect much difference between the four positions.  The tone seems too biased towards bass.  Item 56 shown in the photo is a tone control box with two wires.  One wire (left most arrow) appears to connect to two contacts of the tone control switch.  Item 57 in the parts list is made up of three caps in the box (two .01 mfd and one 3000 mmfd).  Schematic and parts list are at http://www.nostalgiaair.org/pagesbymodel...013824.pdf.  When I recapped the radio, I didn't attempt to get into the box.  I'm guessing the old caps inside are preventing the tone control from working properly.  Does anyone have an easy way to gain access?  Why are these caps in this heavy duty box?  Shielding?  I have a dremel tool and some small thin grinding wheels if I need to cut the box open.

Thanks,
Larry

[RodB]

On my 650 the box came out with the tone control. One side of the box was open and is lined with cardboard which insulated the caps from the box. The caps were potted with the same black substance as the bakelite blocks. Pay close attention to the connections of the caps to the switch. I think the metal box helped reduce the chance of feedback.

[Radioroslyn]

Just for grins you might want to check the resistance from each tone control contact the ground to be sure that there isn't a short in the switch.

[LarryFS]

Thanks for the info Rod and Terry.  I checked for shorts to chassis and didn't have any.  My box also came out with the control.  I'll go slow with removing the black yuck.  And I thought I was done with that stuff on this radio.