My TV only has RCA inputs and no HDMI. Can I still hook up
One possible solution might be to use a small converter that “down-verts” an HDMI signal into AV outputs. A quick check of Amazon shows that these run about $15. I’m not sure how these units would handle the 16:9 to 4:3 picture format change-over, though.
Another possible solution, if you’re using a streaming, networked Tablo is to find a older Roku that has the AV outputs. I don’t think Roku makes them any longer, but they had models in the (oldest) hockey puck style as well as ones that look like the newer Roku Premier units. Both supported HDMI and AV outputs, and the software also allowed you to choose either 16:9 or 4:3 resolution. Someone may have one on Ebay.
A throw-back to the days of a converter box for ASTC from NSTC.
You understand your TV is an outdated antique. If you could, I suppose you’ve already replaced it. But really it’s way past it’s life. Someone somewhere is likely to have an old - yet newer - panel TV they’re looking to get rid of…cheap.