nakamichi pa5 or 7

I'm no expert but I've heard that with time capacitors tend to dry out.

what does that mean if the capacitator dry out, does the amp stop functioning. how do i know if my amp's capacitaor has dry out.

I am no expert either, but I heard that the sound changes for the worse - if you like what you are hearing, I would say don't worry about it. Depending on how the amp was used, it might be still ok - the temperature it was subjected to, and how much it was used.

I have even older stuff I still use without changing caps - 30 years old marantz 2270 receiver, and 20 years old Quad 405-2 amp.

I owned a Nakamichi PA5A MkII. This stock version had 150wpc with large heat sinks and never got hot. The earlier version had 100wpc w/no heat sinks and did get hot. Perhaps, Nakamichi changed the bias between the two versions. I was very happy with the MkII driving my speakers w/ribbon drivers. But, when I switched to electrostatics, the amp was unable power them. So, if you purchase this model Nak, be sure that your speakers aren't too demanding. I don't have any experience with the PA 7. You can find out more at AudioReview.com.