How to reattach Liquid Crystal Polymer Diaphragms in Sony Headphones

[erikbrenn]

Hi,

My great Sony MDR-1R headphones failed today, sound now only coming from one of the transducers. Opening up I see one of the diaphragms has come loose (Assuming that is the diaphragm?)



And this is the other side, which works ok.




Not being familiar with this tecnology I was puzzled, I see no electrical connection from underneath the pcb/diaphgram to the transducer/speaker.

Looks like a thin layer of glue kept it in place... 
Will it be sufficient to glue the diaphragm back with some superglue? 

I tried to press it down using my hands but could hear any sounds from that speaker

cheers

[TheMG]

The blob of glue covers up and protects the wires coming from the voice coil, which are very small and delicate, much smaller than a human hair. They connect to the solder pads on the top side and run down through a little slot/channel covered up by the glue.

I'm afraid it looks like those wires have broken when the PCB came loose. Unfortunately, this is not something that is going to be repairable. At the very least, you will have to replace that transducer, if you can find a replacement.

[erikbrenn]

Thanks! 

I was actually wondering if anything was going down beneath that gunk of glue. But I can't see anything even in my microscope. I guess whatever was there has retracted itself down in the hole there.
Will open it up and post more photos if I see anything

At least I learned something.

[erikbrenn]

Can't believe I missed that...

There are indeed som very thin wires down there, both where severed...

[erikbrenn]

I have separated them from the glue using my finest tweezers. 
Here they are next to a pencil tip,  fragile stuff



Will try to splice them with my AWS 40 or 52 wire    

[erikbrenn]

One down, one to go   

[Gyro]

One down, one to go   

The Force is strong with this one! (in my best Yoda voice). 

It looks as if you'll be able to achieve a successful repair, as long as you can prevent the PCB from tearing off again.

One thing that you will need to get right is polarity (relative to the other earpiece). The best way is to place both earpiece close together and play a low frequency tone through both channels. The correct polarity is the one that gives greatest sound output - out of phase will cancel out.

[amyk]

Great work!

As for polarity, if you get it wrong, don't worry --- you can just swap the far less fragile connections from the cable instead of attempting to redo the microsoldering.

[erikbrenn]

The other wire was pretty hard to do, had no support to hold it against.  I fooled around for an hour swearing and putting everything aside eventually.

Couple of days later I'm back with a vengance.  Came up with a better way to splice thin wires. I cut a tiny perfboard, added flux to help heat transfer around the tiny wires,  and used that as a support to join the wires while adding tin.  Worked pretty well.



To fasten the wires along the cavity I used UV solder mask



I have glued the tiny pcb back using epoxy but will wait until tomorrow to work on attaching the wires....