Hi friends ,last week i bought a Marantz 8 on Ebay. it seems that this unit has been serviced at some points. But i just do not know what has been changed since i do not have any records. Could anyone let me know 1) what kind of service has this unit been done? 2) the seller claim that A1 tube bias can only adjusted half way otherwise, it will be getting very hot..how to fix this? 3) any other services that need to be done? thank you for helping!! sorry for all silly questions.