I am a sole owner of a mint Sansui 5000A receiver and RA500 referb. An incredibly great unit. Never a problem. Treated like a baby.Only replaced 3 lamps over the years. I was wondering if the transformers and power switches can be interchanged between the 5000, 5000A and 5000X Sansui receivers. I would like to get an extra transformer just in case mine fries. Also, my power switch will only work if i hold it in- all other functions are working very well. Is there a simple fix to this switch problem. For the future, would it be worth it if i had a technician check the units for proper values and outputs. I would hate to mess with it if it is seemingly working fine though. I was thinking of purchasing a second unit for parts as my son would love to inherit them. Any advice. Thanks and best regards, chan. 