Think I may have same arm on my LP12. Will look at it.
I have some thick silicone I bought from a Hobbytown store locally.I special ordered because Thorens spec was thicker than store stocked. About $8. They sell it for shock absorbers in radio controlled toy cars. I used it on cue for Thorens TP165 TT. On the Thorens I applied the silicone to outside of the cue vertical shaft. It slowed drop by increasing friction between shaft and tube ID.
Is it dropping too fast? Wonder if you could apply to shaft OD when raised, near its base, without dlsassembling it. I'll look at mine. I don't have a manual on that arm. Did find a similar arm made by a Japanese company on Vinylengine site.