m8 i had the same problem, i bought my 1st pair of 1210's from cash generator for £280 and i had exactly what you are experiencing i bought new concorde dj stylesus and it was the same, i took them back and they said there was nothing wrong, did you buy yours second hand, do you or have you taken your decks somewhere else?
if you have some twat has probably spilt a drink of something over them, because i found out a few month's l8r after buying them they were a pair of battered decks
my advice to you is take them once to be looked at, if they are still the same (cut ya losses and scrap them...
nice 1.