If it's been sitting for years unpowered/unused - the first thing i would suspect is that a electrolytic cap(s) has gone bad.But you know - everyone's telling you to test the tubes for a good reason - cheap-easy - and real easy to fix if some tubes have gone bad - hope that's it.Unfortunatly tubes don't tend to go bad in storage (hence NOS tube prices)-electrolytics will last longer in use than they will in storage (hence no NOS electrolytic capacitors at any price).
Very carefully -and don't touch anything (serious electric shock hazard -even if not plugged into AC power) - take the covers off and using a good flashlight - inspect the base and ends of the capacitors.If any of them are bulged and especially if leaking - they've gone bad and need to be replaced.
Very carefully -and don't touch anything (serious electric shock hazard -even if not plugged into AC power) - take the covers off and using a good flashlight - inspect the base and ends of the capacitors.If any of them are bulged and especially if leaking - they've gone bad and need to be replaced.