As a bit of a caveat, I'll admit I'm a bit neurotic, and I've had a run of bad luck with tech lately. So it's entirely possible there's nothing wrong with my TI at all and that what I'm seeing is normal--I just have no prior experience with the TI and have only seen this one in operation.
Since taking my TI out for more sustained use the past several weeks, I've periodically noticed some screen flickering that doesn't seem to be related to the four-sprite-per-scanline limitation I've read about. I can best describe it as a partial line of dark shadow that comes and goes on different parts of the screen. It's most noticeable when the screen is mostly still, like when I'm idling in BASIC or playing Video Chess. While playing games with more movement on the screen (i.e. Parsec or Alpiner), I haven't noticed this phenomenon as much.
I have an aftermarket 5-pin to RCA connector cable for video display. My power supply seems to be in decent shape, though after three decades in storage the cord is looking slightly worn (but not frayed) right next to the part that connects to the TI. This has led me to think it could also possibly be power-related (if there's even a problem), but again, I'm not sure.
I know it's difficult to diagnose something like this with a brief description. As you all know, we've all become accustomed to the way modern screens and refresh rates work, so while I know the TI displays differently, I'm just not exactly sure how, if you know what I mean. I suppose my question is not so much "Do I have a problem?" as it is "How do I know if I have a problem?"
Apologies if I'm worrying about nothing! I'm really wanting to get into using my TI, and for me a part of that is just getting familiar with how it functions under normal circumstances.