my tt skips

I had a similar problem, now Tt sits on a wall mounted shelf.

To check for bad bearings, balance the tonearm and move the tonearm towards the plater spindle, the anti-skating should move the tonearm back to the rest post. Start near zero and increase the anti-skating if it fails to return, the lower the value the better the bearings as long there is no radial and axial play or slop in the tonearm bearing assembly.
Also verify that the cueing arm that lifts the tonearm is fully retracted prior to the above test.

I had a similar issue with my table, and my suspended floor actually turned out to be the culprit. This was only when someone moved slightly near the table. Eventually instead of tiptoeing through life, I had floor jacks installed in the room below and directly beneath my audio rack. It sounds like your problem is more often than just moving near the table, but I thought you should at least be aware of my issue.

I had a similar problem. I finally determined that the bearing was bad. In my case it required me to buy another arm to make the determination (after trying everthing else I could think of including lubing the bearing). I'm not sure if there's any other means to do so other than having a repair shop look at it. So you'll proably want to listen to other's inputs and try all other approaches such as Raul's above.

Dear Triangle: There will be some problems that you could have: the resonance frequency between your tonearm and the cartridge is really out of range ( 8 to 12Hz ), feedback from your speakers, vibrations from your rack/plataform TT, tonearm bearing out of work, tonearm antiskating out of work, faulty cartridge suspension, oil damping? etc, etc. You have to check all around.

You can check with other cartridge, with and with out antiskating, with and with out oil damping, etc, etc.

Regards and enjoy the music.
Raul.