Crackling Sound in Normal Channel of 63 Bandmaster

[bobtec]

After the amp has been on for one hour ,If I tap the top of the amp I get a crackling sound with just a tiny bit of hum.I cleaned all the sockets,but that first .1uf cap is microphonic The tubes are OK, I have changed everyone...If I pull out the 50 yr old plate resistors ,should I just cut them off at the joints,or should pull them out.I do not want to make things worse and pull a ground wire out too.Would it take a hour for a resistor to start to act this way...I just was trying to see if I can do it before shipping it off for a month and $150.00 The amp sound really good for that first hour,Then I start to hear a slight distortion,Also for a while the Volume pot would be scratchy that has stopped,but it is noiser than the treble and bass pots

[bobtec]

i FIXED IT..BAD PLATE RESISTORS....drifted way up