Nak Stasis Receiver-Help for service

I have always had a soft spot for Nakamichi Stasis Receivers. I just recently purchased an SR-3A for a second system. This unit is almost 20 years old and I'm sure it's never seen service. I know the Stasis circuit is a pretty simplified version of Nelson Passes original design. I was wondering if anyone could tell me what area's may need to be checked out due to the age of the unit? Also since Nak no longer services these, where can one send it to get the proper service done and make sure it's still in spec? Do most reputable service centers know how to service this unit?

The reason I ask is I've been comparing this unit to my Nak CA-5/Adcom GFA545 seperates and the Nak just sounds off. It has a rather bright/forward sound and the bass seems bloated and sloppy compared to the seperates combo. I remember, from many years ago, that these were very good sounding receivers. I really want someone who knows what they are doing to try to get this SR-3A back into spec.

Any suggestions would be extremely helpful. I hope I'm in the right forum