AC30 TB Problem

G'day All,
Just a quick Q about my 67 AC 30 TB. Maybe some one can help. When I switch it on I get a slight crackle sound and then when I plug in the guitar lead no volume comes. Sometimes when I turn the vol. up full and pull it back it starts to operate normally. Then sometimes if I switch the amp on and off a couple of times it also starts. I have checked all the valves and have sprayed CO Contact spray all around the place. Any ideas what the problem might be?
regards
Buckshot
Just a quick Q about my 67 AC 30 TB. Maybe some one can help. When I switch it on I get a slight crackle sound and then when I plug in the guitar lead no volume comes. Sometimes when I turn the vol. up full and pull it back it starts to operate normally. Then sometimes if I switch the amp on and off a couple of times it also starts. I have checked all the valves and have sprayed CO Contact spray all around the place. Any ideas what the problem might be?
regards
Buckshot
