Yamaha psr-270 keyboard almost all keys are not...

Question

i had this 61 key keyboard for about 9 or 10 years and i constentley played it. at first 2 keys did not work then i tryed to clean the contacts with water but it only got worser. now only about 10 or 15 keys work. it also has touch response. can someone plz help me?

p.s. it is not a amp. i just can't find the musical instroments