hey guys, i was wondering if someone here would be able to help me. i am currently using a GK 400 rb bass amp head which looks like it was built in the 80's and am having a problem with it. sometimes it doesnt turn on at all, and it seemed like it was pure luck that it did turn on until i discovered that it will work if i turn the volume knob up to about 2 o'clock. it then bursts on to that volume and doesnt work unless i do that. i was wondering if this would be a fuse problem, or if the amp would need time to warm up , or what? any help would be appreciated thanks.