01-31-2020, 11:56 AM
I agree with Terry and you need to see if you can get the tubes tested. All electrolytic and paper/wax capacitors should be replaced and the value of all resistors checked. Once that is done, then you can begin to troubleshoot. I suggest you start at the output side and work your way back. There are numerous videos and discussions out on the internet that describe the process.
Bill
Bill