Home Theater Questions? Ask a Technician for Answers ASAP
Hi Fred and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, bear with us; re-confirm and post back with the complete model number of the NAD.
Still, the described symptom almost always point to an internal hardware issue. Are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even perhaps a soldering iron?
The description of "...lost most volume on one side..." may be as simple as am erring control such as the volume or balance where cleaning may be attempted using compressed air or better yet, plastic safe / non-staining DeoxIT DN5 or LPS 03116 Contact Cleaner or equivalent to clean the insides but allow sufficient drying time
a failing 'right' channel amp circuit that would need parts replacement.
Either of the above would require that the unit be opened up for visual inspection, even voltage/continuity/resistance checks, confirm faults and effect repairs.
I realize that the above information may perhaps be not what was expected. Unfortunately, there is no quick-n-easy fix and neither is there a workaround; sorry for having to be the bearer of bad news.
Should you be uncomfortable with a DIY, perhaps your best bet would then be to consult with and/or seek the services of an independent repair shop / qualified professional.
Good luck and thank you too for the opportunity to be able to exchange information.