Polk SDA SRS 1.2 issues

   Hi guys...I'm new here and pretty new to vintage gear (only bitten by the bug about a 1 1/2 years ago). Here's my situation; I have been lucky enough to pick up a Pioneer SX 1250 which is pushing my SDA 1.2's (not the minimum 200 WPC recommended for these, I know) and was going along very nicely for some months until I played my turntable (Pioneer PL-A35) and noticed the left channel was barely audible. I tried other inputs and everything played normally...for a while. I should mention this system is at our cottage so I only get up there every month or so and I haven't been up to try and trouble shoot it (in the rudimentary level I'm capable of...my knowledge of electronics pretty much begins and ends at connecting my system and enjoying the heck out of music).
    Anyway, I did switch speakers to rule out the channel being shot so now I know it's the speaker itself as it plays at that same barely audible level regardless of the source. So, apologies for being longwinded and thanks in advance for any help you guys might have...cheers!