[NostalgiaRadioTime]

I've had this set for a number of years and even after restoration, it has had a crackle on the AM band that I couldn't get rid of. So, having some time off of work (using up PTO before the end of the year), I decided to pull the chassis and give it a more thorough check. All the wax and paper caps were changed, as well as the electrolytics. Tube swapping didn't make a difference, so I first though the problem was with the 7X7 tube socket. It was very sensitive to touch...it would bark back and honk and sputter at just the slightest touch. So, I replaced the tube socket. That didn't solve the problem. Thought it could be the R101 candohm, so I replaced that with a 150 ohm 10 watt. The problem is still there.  Thoroughly cleaned and flushed out the tuning capacitor. No change. So I'm left with a radio that crackles on the AM band, but mostly on the lower end. When I push the button to change it from radio to phonograph, the crackling stops, indicating the problem is before that switch. It also fluctuates in volume a bit. When the crackling stops, the volume suddenly gets loud. When the crackling starts, it quiets back down. Thought it could be the volume control, so I tried a new pot. No difference.

The last test I did was removing tubes to see if I could isolate the problem. I take out the 6BA6 Tube and the crackling stops. I put that tube in and take out the 7F8 Tube and the crackling is there again.

Voltages are steady but on the high side:

Section 1       VDC normal           VDC tested

(test points
as per SCH)

E-C               240                       278
D-C              190                        213
A-C              310                        352
B-C              -16                          -16

Plate to ground VDC

                         Should Be                           Measured
6V6's                    235                                     274
7AF7                    165                                     184
7R7                      235                                     274
6BA6                    235                                     274
7F8                        95 on AM                           104

Here's the schematic:  http://www.nostalgiaair.org/pagesbymodel...013606.pdf

Any help would be greatly appreciated. Has anyone else experienced this on this model?