High-Volume Playback system maintenance

When mastering a track I often find it necessary to play back at high volume on a simple system (e.g. stereo-only). My studio monitors are decent, but they kneel before the bellowing, grindcore rig that was given to me by a dear friend who was stomping around Chicago’s industrial scene back in the 80s.
While it does play quite loud it’s seen some heavy use, so it needs a tune-up every so often. Today was just a dirty pot-scrubbing, but I fear more substantial trouble on the horizon. It smells like a hot lamp inside a musty library. <deep inhale> I love this hunk of junk. It’s sure to collapse someday…

..but today is NOT that day!