I can only comment on Nak decks, as i have most of them. The lx3 is a sankyo transport deck which is very good. If the deck has been sitting for years not used it will most likely have dead spots in the reel motor or cam motor and or the idler tire will be dried up or cracked or worn out. When you get the deck,test it with a cassette in it. Check ff and rewind. Should be fairly fast rewinding or ff a 90 min tape in about 90 seconds. give or take. Also, with a tape, let tape play for the whole tape. Should obviously play a whole tape. What i do to test for dead spots in reel motor is.If there is an auto repeat switch on the lx3, most naks have auto repeat.I switch it on, throw a tape in and let it play for hours,it will rewind automatically and replay the tape forever. Come back and if the tape has stopped anytime then either the tire is toast or reel motor has dead spots.
LX3 is a good deck and fairly easy to work on. Tire is easy,reel motor not so much.