Looking for RL02 cable and terminator

[Gordon JC Pearce]

> If you want to keep your disk cartriges clean, change your absolute filter
> and clean the head, and don't switch disk carts too often.  My main system
> RL02 has been running flawlessly with the same disk pack 24/7 for 2 years
> now, and I haven't even changed the absolute filter yet.

On that note, is there a way to tell when the filter is getting "done"? 
  I don't want to risk damaging my drives, but then I don't want to use 
up my meagre supply of spare filters too...

Gordon.