Troubleshoot NAD 3125 integrated

I'm using a NAD 3125 integrated I bought new in 1985. This was my home study system, recently promoted to main system following the demise of my main power amp. It drives a pair of RDL speakers (Roy Allison's last company).

One channel has somewhat lower output, particularly in bass. (Checked by switching speakers and playing test tones.) I'm consdiering buying a replacement, since it costs $100 plus just to have service center evaluate. Plus repairs. Does this type of problem sound familiar? If this is simple and common, I will fix, otherwise go for new NAD C320BEE or maybe Cambridge Audio 540.

Would appreciate any comments.
Taking its age into consideration, I'd say you have a few dried up electrolytic capacitors. It wouldn't hurt to rebuild the amp with all new ones. You can go the cheap route and just buy cheapies, or you could spend plenty and use all Blackgates or similar audiophile caps, but the cheapies will work fine and probably cure the problem.
I have the same amp, much the same story - it's been a solid amp for 20 years. Recently, the left channel has started dropping out intermittenly, with only a small amount of power delivered on the left when this happens. Switching amp to mono cures it. Problem is more evident with a lower level input such as 4125 tuner, as opposed to a CD/DVD input. Visual inspection shows no obvious problems, cracked solder, etc. This is the first I've heard of dried up caps - are they likely to be the culprit in my case also? ps: I notice you're local to Victoria, BC. Any recommendations on where to find caps in Victoria?