Hello,
Your tonearm is a japaness source like the linn basik LVX and the revolver standard. The systenmdeck IIX is a turntable from the late 80's made in england. I see several possibilities about your problem with the arm. Firstly, the wooden plate is not screwed tight against the metal plinth. Secondly, the round black plate at the bottom of the arm is not screwed thight. Lastly, the screw at the right side of the round black plate is not screwed thight. Caution! don't overtighten the screws because you can damage the arm or the turntable. You can do that by yourself but after that it will be important to verify the adjustment of your cartridge versus tonearm. A good technician in a serious Hi-FI shop can do this for you or you can do that by yourself if you have enough konwledges in this domain. You must verify the vertical tracking angle, the antiskating, the parallelism of your cartridge with the groove with the help of a gauge and the reading pressure in grams or millinewton (for this thing you have a rotating knob at the end of the arm). You can obtain good advices about that from the website of UHF (Ultra high fidelity magazine) or the vinylengine. If your cartridge has a replaceable tip, you should verify that with a microscope in a serious HIFI shop. Maybe the stylus is damaged? That's why you should do that also. Lastly, maybe the springs of the suspension are not aligned well. It's important that the platter is parrallel with the wooden plate. Also it's important that your turntable is parallel with the floor. You can put a bubble level in the center of the glass platter and after that on the wooden plinth in two ways from front to back and from left to right in each case. This adjustment must do in first before any adujstements on your turntable. I recognized that my explanation is not enough clear about the adjustements. My goal was to give you the chance to become aware about how to adjust a turntable. Probably, a good HIFI technician will be the best solution for you!