I've got this CLD-97 that will, if left off for a day or two, will need to "warm up" before playing a CLV disc.

By warming up, I mean it will play a CAV disc without issue normally. If you try to play a CLV disc, it will start but then stop after a few minutes with no error code.

If you let it play a CAV disc for one side for 20 min or so, then put in a CLV disc, it then works normally. Sometimes it will stop while playing a CAV disc too on the first try, but will work when restarted.

Any idea what's causing this? Is the spindle going bad or something (hopefully) less drastic?

Might be a sign that some of the capacitors are bad.

I was thinking the same as well. If the spindle is actually going bad, you probably couldn't play any discs. How does it deal w/ CD playback?

I tried playing a CD in it. Starts up fine, but when I tried to skip to the next track it stopped.

Almost anything that needs to warm up probably needs caps. In a system this complex though…it’s hard to say where. Probably not in the PSU though, would be my guess.

When playing well, is the picture good?

Warming up and failing is also a common issue with IC's or semiconductors. Get freeze spray and try spraying IC's to see if you can keep it working.

The picture is a-ok. No complaints there. No snow or interference.

Any particular place I should aim on the IC's when it's playing a CLV disc to keep it going?

Flip out the top video board to access the main board for the main board IC's to spray.