AKG K 206 Consumer Headphones "k141" Questions

how can i open my AKG k141 studio headphone to repair it ? I had a problem with my AKG K141 Studio headset. The right side stopped working. Hard to believe but one of the leads to the ear speaker was ...

I own AKG K141 MKII headphones that now play through both the left and right headphones but often only high frequency parts of song without bass part. When I fiddle with the cable where it connects to