I have a 77 concert bass amp that has been making a crackling noise, if you hit the top of the head it goes away for a little while, I was told the connectors between the power and pre-amp are probably dirty or loose, I opened the amp and pulled and cleaned the connectors The red wire and the white/blue striped wire, problem is I'm not sure if I got them back on the right connectors and I don't want to turn the amp on until I'm sure,I feel embarassed by such a stupid mistake but I just wasnt paying attention when I pulled them off!!! Does anyone have a photo of the inside of a concert amp or can just tell me which posts are the correct ones? I believe they go on the second and third post from the corner one with the red wire that is going to what appears to be one of the two large grey capacitors!!