My x-axis belt adjustment knob just ‘rachets’ and makes no apparent change in the belt tension unlike the y-axis knob which moves smoothly. What is the purpose of the screw on the face side of that control ’box’?
Thanks, Bruce
Welcome to the forum.
The screw head visible in the slot (viewed from the front) is the axle of the belt idler pulley. It is structural not an adjustment and should be tight when the printer is running.
This makes me think you have a stripped thread, probbaly the brass insert in the center of the U shapped piece that the above mentioned screw threads into.
Thanks. The insert appears to be the same blue plastic. Is there a way to dis-assemble these parts?
Carefully. 
I’ve never had mine apart but if you keep unscrewing the knob I think it will come completely out. At that point grasp the belt and pull. If the belt idler won’t come out you will have to remove the assembly from the gantry. Behind the printhead find the ends of the X belt and slide the one on the right out of the slot. That will give you slack to work with.
I’d remove the idler from the bracket and thread a LONG screw through from inside and use a nut where the knob was. You can print a new knob with a captive nut once you are up and running.
Thanks. Probably won’t do that. I tried to find a replacement belt adjuster with zero success even at Sovol. Very few parts available anywhere. And they don’t seem to sell the svo7 any longer. Did I buy the wrong printer?
I think this will work for you.
https://www.thingiverse.com/thing:2854971
Contact Sovol support, they have access to parts that aren’t in the retail store.
@sovol3d