Superlux HD681 problem

[Mingo]

A few years ago you modified Superlux HD681 for me.
These days I use them with my electric piano and they have been great.
Now something has happened, as I can only hear the signal in the left channel and the right channel is 100% silent.
Even if I pull the plug or the cord there is no noise or hissing at all. Have you any idea as to what could be wrong?
Help is greatly appreciated!

[Solderdude]

It is most likely a loose soldering / broken wire.
If you have a multimeter it will be easy to check what is wrong.

Also you need to take some pictures (sharp close-ups perhaps) and open up part of the headphone.

This involves removing the round nameplates which can be pried off carefully and a tiny Philipshead-screw that must be removed.
Underneath a few wires are soldered and that is where we need to measure.

The drivers most likely won't be faulty, but as the filter components do have some mass it is possible they came off from the PCB when it has been dropped.

Can assist remotely using skype if needed.

[toppe]

In a similar thread, but in danish, Mingo explained that by moving/pulling the jack-plug he could recieve the signal from left channel to both drivers in hd681 when used with his electric piano - he couldn't reproduce this from other sources/players.
I'm not technical, but couldn't this indicate a problem in the jack-plug end and not the other? I don't know how the mod works, so I might very well be way off
Hope you solve the problem and that it's a minor and trivial one that's easy to fix

[Solderdude]

In that case the drivers (and filters) are probably still O.K. and it seems to be a question of a solder joint that has come loose.

What cup is not making sound left or right ?

[Mingo]

Right cup is 100% silent.

[Solderdude]

Most likely one of the wires to the rods may have come loose.

On both sides remove the nameplate and the small screw found underneath.
remove the cap and touch the wires connecting to the rods.
If any of them are loose they need to be soldered on.

[Mingo]

My problem has been fixed!
As you and Claus stated, using a multimeter helped.
It turned out that a wire which should have been connected to a rod was loose. After I soldered it back into place everything was okay.
So thank you very much for your help! Everything is much easier when you are pointed in the right direction.

[Solderdude]

Glad you got it sorted.
Soldering wires onto the rods is a bit cumbersome sometimes....