Help With 400

Hey,    well here it is.    i picked up an atari 400 with a 401, 1050, and a 1025 all for $40  at a local store.   heres muh problem   it works so far but   i cant use it  lol. the keyboard dose not work  the system reset  and break keys do.  well  i looked into it   and well  the keyboard does work i tested it with my multimeter cant say all keys do but more then the 2 that work when its fired up.      so  the next thing i did was look into it more  found that the pokey chip  did most of the workins on the kb. well i figured  it was bad so i pulled out the 5200 i had layin around and swapped the chip........    still no go        does anyone have any ideas on what else it could be???   i would love to get this thing working again  ive always wanted an atari computer now i have one but it needs some TLC!     Thanks