Nakamichi PA-7A MKII repaired and like new again.

2 &1/2 years ago I posted a 'To recap or not' thread (https://www.audiokarma.org/forums/index ... ot.940181/); a few months after that thread I took both the amp and pre-amp to Chris Bridge who did all the Nakamichi warranty work way back when, BTW he also did/does Carver, Adcom and a whole bunch of other brands.

In spring 2021 he checked both units out, made a few adjustments and said 'don't mess with these' wait till something goes wrong... if it ever does..
His reasoning was simple... he's never repaired any of the NAK 7 series under warranty, when it comes to the amp all the repairs have been to undo DIY type 'upgrades' in the past 15 or so years.

A year later( a few months ago) something finally did go wrong with the amp. a popping sound after the relays kick in with the pre turned off so whatever the problem is it's definitely coming from the amp.
Chris found the problem by tapping on the thermal switches directly. He also made other repairs to degraded components by replacing the relays, feedback capacitors & resistors, protection circuit caps, found some transistors running hot and replaced with matched pairs that are better able to dissipate heat. Also re-soldered some cold solder connections.

Got it back a few days ago, sonic signature at low volume is better matched then they were before, i.e. amplitude at various frequencies are identical in both channels. Even at 32+ years of age this amp still sounds great.