Hoping someone can help with this one. I recently picked up an old world tour 800B and love the tone. The issue is after the amp gets warmed up the the A power amp side starts to get scratchy and eventually loses most the signal. I have switched around cabs and it is definitely something in that side of the amp. I love the tone and am considering repairing it but concerned it maybe a serious problem. If it is too much money I have 30 days to return the amp. Thanks in advance for the help!