[beginner1]

Got some new games to play so dragged the MMX300s out and have noticed at the thing where the cable splits both the headphone and mic cables are pulling out - there's just bare copper exposed as though I've been putting them under heaps of strain.  Don't imagine I can open up the splitter thing so looking at replacing the entire cable, I'm handy with a soldering iron but not sure how to get these things open, where to get a replacement, or if there's any opportunity here to upgrade the cable.  Anyone worked on a pair of these before?

 

[GREQ]

I've got a DT790, which is essentially a studio version of the MMX300. 
(most Beyerdynamic studio models share the same essential frame/parts)
I replaced the entire cable, but I didn't have a Y-split enclosure handy for a tidy finish where it terminates with two plugs, but it was easy enough.
 
To open it up, just take off the ear pads which just slip off.
 
Then you need to pop out the retainer ring around the inner baffle.
I would use something soft and blunt like a thin flat-head screwdriver.
note: this has a specific orientation and needs to go back in exactly the same way.
 
After the retainer ring is out, the baffle with the driver will simply fall out.
 
After that, it's just a bit of re-cabling and soldering. Easy. 
 
_____________________________
 
Someone else has already made a few photos of Beyerdynamic monitor-style headphone disassembly http://www.head-fi.org/t/645691/disassembly-how-2-on-beyerdynamic-dt-770-pro-80-ohm-with-photos
MMX300 should look pretty similar if not identical inside.

 

[beginner1]

Cool sounds straightforward enough.  Would 4 wires to a TRRS work with L/R/Mic and a common ground?

 

[beginner1]

Working on this now and I'm a little stuck...  I desoldered the existing wires from the pads labelled 1 - 6 but I'm not able to determine which pad is for what.  I tried looking for continuity down the wires with the DMM but I'm not even getting a reading off these things 

 

[GREQ]

It should be somewhat easy to determine on the PCB where the signal travels.
Maybe you need to unscrew the PCB and have a look at the electrical traces, and see where they lead to. It could be the traces are on the other side you can't see.

 

[beginner1]

  It should be somewhat easy to determine on the PCB where the signal travels.
Maybe you need to unscrew the PCB and have a look at the electrical traces, and see where they lead to. It could be the traces are on the other side you can't see.

 
AH!   Yeah that should work. I'm most of the way there, got the drivers going but mic not working, will pull them apart again in the morning and take another look

 

[beginner1]

Argh that took longer than it should have.
 
For reference
 
1 - Right
2 - Left
3 - Ground
4 - Mic Ground
5 - Unused - Mic R?
6 - Mic +
 
And soldering the little connector sucks

 

[mmx300poop]

Argh that took longer than it should have.

For reference

1 - Right
2 - Left
3 - Ground
4 - Mic Ground
5 - Unused - Mic R?
6 - Mic +

And soldering the little connector sucks

newbie here trying to also replace my cable, no soldering experience so gonna be hard but i try, problem is i have no idea how to find correct cable that works with mmx300. any recommendations for 3.5mm cable that has mic wires too for mmx300?