T-65C Tonearm Lateral Balancer?

Newly purchased (used) Harman Kardon T65C turntable has straight tonearm with lateral balancer. Can anybody explain it's purpose? The T65C has a straight tonearm with an effective mass of 9.5gm (plus the mass of the cartridge used). The instructions simply say to place the lateral counterweight closer to the pivot when the tonearm counterweight is positioned at the end of the shaft (heavy cartridge. Also, can it's effect be measured or noticed using a test record?
Appreciate your info on replacing the caps - I am having the same problem and will replace mine, as well.

I am looking for an HK T-65C lateral balancer, as well as some other parts for this TT. Are you interested in selling anything or know where I might be able to find parts for tonearm and platter?