Northstar: thanks for the link.
Tapetech: records wobble which causes the tone arm to move up and down. Can’t tell if the platter itself wobbles. It’s hard to see if the platter is wobbling without anything on it. I was thinking I might need a new belt. The belt actually fell off while playing a record a couple of months ago and I had to put it back on. It’s been ok since then but it might be time for a new belt. TT is about 5 years old and I use it a lot.