To connect to your TV you will only need a cable from line out on your TV to Tape 1 or 2 on your BM probably RCA to 5 pin DIN.
You can get that from Steve at Sounds Heavenly, if you have an Ipod or another player get a cable to connect that one too, Steve will sell you the right one.
To check your speakers take of the front covers and inspect the drivers, as Martin explained check that the surrounds are glued to the metal basket. If you have a multimeter or a ohm meter, check resistance between the round and the flat peg on your speakers.
If your BM 4000 is repaired by a profesional it will not break down again, the main reason they brake down after repair is because the repairs are done by amateuers like me, we love repairing and after one repair we only wait for the next breakdown, and with entusiasm we take the item apart and "repair" again.
If you dont know how to solder and if you dont know just a little bit about electronics, then dont do it yourself.
Use the search function on the forum, check for speaker repair, BM 4000 repair and so on, you will find a lot of information.
You can read about your BM 4000 here and nearly every other B&O made model here
Beosound 3000, BL 4000, BL 8000, BG 2404,BG 5000, BG CD50, Beocord 5000, BM 901, BM 2400, BM 4000, BV S45, BV 3702. There is nothing we cannot do, but a lot of things we don't want to do!!