The best way is with a strobe disc. Get one that is smaller in diameter than an LP. Gently place it on top of a record on the platter. I keep an old beat up LP around for just such things.Got the new belt on, it definitely turned without an issue like the old one had but then I noticed it was playing things verrryyy slow.
Ive since then adjusted the pitch control and it seems like things are running as normal but I'm not feeling like I don't have the pitch dialed in accurately. I used a phone app put the phone on the table and I come approximately close to the expected speed. How would I be able to ensure I've got the right pitch?
I'm planning to take this in at the end of August when the guy at the use gear shop is back from holiday to get it properly tuned up.
Then play the exposed part of the record. You’ll be able to adjust the speed while taking account of stylus drag.
Accelerometers in smart phones aren’t really precision devices.