100 J issue with sound

[prime]

Hi guys i have a J that has a bit of a sound issue, mech and amp didnt work when i got it, I replaced all of the paper caps with mylars, i did find one of the old caps had broke of of its post but that has also been replaced, cleaned all sockets and tested all tubes, replaced the RCA jack for cart input because the old one was butchered, I get about 80% of volume that i am used to with other units,  i also get a bit of a hum, the kind you get when touching a mike so ground seems to be the culprit. I noticed when i remove the metal cover on the 5879 tube it caused a bit of the same sound when i touched the tube, that may be normal or is that where i should focus for ground issue

[jukeboxmarty]

It's sometimes difficult to resolve ground hum issues... but your experience with the 5879 tube is fairly normal. That's why they put the shield over it. You can probably introduce hum just by waving your hand close to the 5879 without touching it!

[prime]

Good to know, i have gotten it closer to 90% volume so i may leave well enough alone. I had cleaned all contacts with Deoxit-5 but while looking at the bass switch at the rear i noticed the copper at the switch was quite tarnished. I cleaned it with 2000 grit sandpaper and it improved volume. pete