Having trouble with Teres Audio VTA adapter

I am trying to set up my Teres turntable again. I have not used the turntble for a few years and when I tried playing a record, it was obvious that things were out of adjustment. My Teres turntable is one of the older models; I purchased it in 2005, I believe it is a 165?? Anyway, it has gone through some upgrades, including replacing the lead-filled acrylic platter with one made of birch plywood, a different motor/battery set up, etc. I also added a Teres VTA adapter.

I am trying to set the VTA before checking the cartridge alignment. The rear of the tonearm, a Moerch DP-6 with a 12" arm tube, appears to be slanting down slightly so that it is slightly higher than the cartridge end. My understanding is that the tone arm should be basically parallel with a record set on the platter. I have twisted the knob on the VTA adapter from 0 (zero) and all the way up, but I can not see any change in the position of the tonearm no matter where the Adapter is set.

It has been years (3-4) since I have "played" with this turntable and I have forgotten the little I knew..... :-o No instructions came with the Adapter; after all, its operation should be pretty obvious and straightforward...
What am I doing wrong here? What obvious thing am I missing?

I'm guessing you loosened the side screw stop?
Hi Holly, I agree with Lak.

Your Teres 160 has an acrylic armboard. On tables with hardwood armboards, Chris often glued the VTA adapter in place. On acrylic armboards, the only thing holding the adapter is a set screw, which may have loosened up over time.

The screw is accessed through a hole at the outer end of the armboard. You'll need the right sized hex key.

I'm not sure exactly how the screw interfaces with the collar of the VTA adapter. It may screw into a threaded hole (best), tighten against a flat spot (better) or just tighten against any random spot on the collar (oh well). If it's meant to hit a particular spot, that spot may have rotated when you attempted to adjust arm height. Check that before re-tightening.
I agree with the above comments. Either your VTA adapter is loose in the armboard or the arm is loose inside the adapter.
Thank you all very much for your responses. I had not loosened the screw for the adapter to the tonearm; both the VTA and tonearm are securely fastened. I don't know what I was doing - crossing my eyes?!? - but I managed to get the VTA set correctly yesterday evening, at least the arm tube looks level with the record to me!

Still no joy with the turntable, though. I am having a problem with the sound being very distorted now, but I will start another thread because I don't believe it has anything to do with VTA or the adapter.

(Why is it that even when logged in, you have to put in your Username and Password again under your post? Rather annoying! )