Need advice please

I recently purchased a Nakamichi PA-7II amp.  I already have one and wanted another to expand my system.  I paid $2000 for it.  Looks nearly mint in original box.  However, I have a crackle from the left channel when playing music at low volume.  It is in fact coming from the amp determined through process of elimination and by switching out components.  Estimated cost to repair the issue is only between $100-$200.  I have always thought that this particular amp was Nak's finest and is becoming the most rare to find these days.  I have an opportunity to return it to the seller.  Is it worth keeping and getting repaired?  Thanks for your opinions. 
I already have one and wanted another to expand my system.

  Is it worth keeping and getting repaired?

see if the seller is willing to split the cost of the repair bill vs packing the amp up and risking the amp getting damaged in shipping 
$2,000 seems steep to begin with. Be surprised if the previous owner is willing to pay any for the fix as it’s used and fairly old. You can ask but I’d say you really wanted this amp for what you paid so probably just makes sense at this point to keep and fix regardless and hope the estimate is close to the final bill.
Not many worthwhile things in this hobby cost $100-$200.  I’d just bite the bullet and go on enjoying your amp.  Life’s too short. 
THat's a good price.  Do it.  Also though, check the state of the filter caps.  Those amps are worth recapping too. They may sound better and will prevent failures / complete loss later on.
do it

no brainer if you like the amp