Problems with a TT Technics SL D3

Hi, I need some help:

I found a turntable Technics SL D3. It looks a little old but nice.

First of all I would like to know if it is a decent one, a good one, or just junk?

I haven’t one enything on it even clean it,just downloaded the manual. But I have some problems and I don’t’t want to start messing up before I receive some advice.

A) When I put a record, especially at the beghinning, it has problems to maintain the speed. It is erratic a few seconds faster and a few seconds slower. After the first third of the record it stabilizes. Do you know how to solve the problem?

B) I hear better the left channel than the right. It looks like a problem of the cartridge, I mounted it on my TT and the same happened but more noticeable (I don't understand why). Any idea to solve the problem?

C) Would you suggest to change the tonearm cables? If yes which cables should I use (maybe the cables of a CAT 5 computer network cable)?

D) Any other maintenance operation to be made or suggestion?

Thank you for the help