Hi
This first post at head-Fi is caused by a sporadic aution buy of a pair of Stax SR-X (MkII) / SRD-5SB.
From the seller I uderstand that they are really slow starting up, and also suffer from a sligt channel inballance.
From my understanding a membrane cleaning and recoating could be needed.
 
I have searched, but have not found any clear information about how this could be done.
Could anyone advice me where to get a better understanding how this is done?
Pix

Coat the membranes in anti-static cleaning gel/fluid, and be prepared to do several retries. I hope its just a recoating that's needed, channel imbalance could also indicate a damaged membrane.

Thanks for the advise, but is there any tread you could forward me to see how this is done?
I think I have the skils to do it, but some pictures could help me, avoiding to demage anything when disassemble the phones.

The "DIY electrostatics" thread is probably the most useful thread for this. If the SR-X mk2 driver design is the similar to the SR-5/SR-Xmk3, just be careful not to put too much stress on the small silver wire connecting the back and front parts of the driver while you're disassembling the driver, and also don't poke any holes in the dust cover if you can help it.
 
Chinsettawong uses a soft sponge to apply the coating, which is probably the safest way to do it.
 
You may also need to do some dust removal after you're done - this can be done by using some mild sticky tape on the metal stators to pull the dust off, and very carefully dusting off the membranes.