The other MORE LIKELY CAUSE is that one of the cables has snapped off from one of the solder joints in the right ear-cup.
For someone who knows AKG K141 anatomy, this is a 5 minute repair job.
- First you need to remove the shiny 'AKG' logo using a toothpick or tiny needle to initially pry it up a tiny bit, and THEN slip in something like a guitar pick or credit card to get it all the way off - this prevents you bending or denting it, which is ridiculously easy to do.
- Then you unscrew the tiny screw in the middle of black plastic cover; remove it revealing TWO solder joints connecting a red wire and a white wire from the headband wires to the right driver (which is you can't see yet).
- If these two wires are secure, proceed to unscrew the BIG BRASS screw that the small plastic-cover screw was threaded into.
- Now the whole cup should be loose and fall off the headband - the ONLY CONNECTION to the headband now is those two wires.
- If one of those wires is loose, it should be REALLY obvious, and should be re-soldered.
- Now test the headphone BEFORE reassembly (because it takes a long time to disassemble again if something went wrong).
- If this didn't work, the next most likely cause is that the
connection to the right channel is
broken in the left side where the cable enters the headphone - which is less likely and more difficult to fix because there are more wires to get confused with.
If you can't be bothered then I'll be happy to nurse it back to health.