Slightly ill MD441

[ln76d]

Yes, it's probably diaphragm, maybe not dead but i think the glue is weak.
Try to take off this "trumpet" tube. Look on photos from previous posts.
If You take it off, do a good photos of diaphragm from few angles.
If it's glue from the outside edge of diaphragm and if your hands are smaller than bears have - you should fix it.
Worse if it's glue what holds coil into the diaphragm - not always to fix - depends on your manual ability and the glue from the edge of the diaphragm. It's truly easy to break coil wires.
I doubt that sennheiser repairs cases like this, so you have nothing left to lose.
Probably they will try to sell you a new capsule, which can sound not that good as this old. I didn't compare new 441 with the old one, but looking on md421, which they sounds different, probably the newer one will be worse - but that's only my opinion

 

[mindlessstudio]

Right-o. When you say trumpet tube, do you mean the white fabric bit?

 

[ln76d]

Right-o. When you say trumpet tube, do you mean the white fabric bit?

Look on photo, where i wrote - pull off both sides - this is the ring which you should take off first.

 

[mindlessstudio]

Yeah, I tried – but I can't seem to work out how and I'm afraid to cut things that shouldn't be cut. As far as I can tell, the ring that you've circled is part of the bigger black tube with square holes in it, and not a seperate ring – I might be wrong, but it looks like it to me. I tried sticking a scalpel underneith it from the 'white fabric side', which didn't work. And I can't get anything underneith it from the bigger black tube-side at all. There simply doesn't seem to be a joint. I'm sure I'm doing something very basic wrong here ...  :-[

 

[ln76d]

It's plastic or metal - this ring?

 

[mindlessstudio]

plastic – and I can't see any metal tings at all in that area ???

 

[ln76d]

plastic – and I can't see any metal tings at all in that area ???

Sorry, maybe i was wrong with this ring. I really don't remember how it opens, it was a few years ago. I'm look at this mike in 2D only.
I'll let you know tomorrow, because i need go to sleep now.
I need time to think about

 

[ln76d]

If you want to fight with this diaphragm still, i need to see this capsule from few angles - several good photos will be helpful.

 

[mindlessstudio]

Ooh, I missed that post, sorry!

Well – I can't really work out how to take the capsule apart. You mean just some pics of it whilst it's NOT taken apart?

 

[ln76d]

Just do a few pictures for me and we will see. I need to find where it opens up.
I'm not sure, that this all black plastic part shouldn't be moved up.

 

[mindlessstudio]

Okidoki. Here goes then. Hope this helps

 

[mindlessstudio]

One more

 

[mindlessstudio]

Aaand one more.

 

[mindlessstudio]

The yellow wires are just for the test, you suggested btw.

 

[ln76d]

In place where white coat ends, there's no visible horizontal junction?
Try to remove this white coat first - we dont need it for now.
Try to do that carefull, because you will need glue it again

 

[ln76d]

If you didn't take of this coat, leave it for now.
Look on photo:
http://www.gearslutz.com/board/attachments/low-end-theory/198457d1287388414-sennheiser-md441-bad-soldering-repair-md441_top_02_arrow_small.jpg

There's a screw in a "hole"

Try that first

Probably on the rest of these holes is glued.

Here's the photo of the inside:

http://www.flickr.com/photos/31603983@N05/7303811878/in/photostream/

 

[MicDaddy]

The whole resonator assembly pulls straight off from the address end.

Look for 2 screws, covered in an orange glue/sealer.  You may have to remove these screws to break the bond, then the resonator will be easier to pull off.

The 2 screws do not hold down the resonator, but the adhesive covering the screws is going to pin it down to the magnet structure.

I have taken some photos but too large to upload, once I can re-size I can upload to show how it pulls straight off.

edit: From the photos above, it 'looks' as if the two screws are potted with a black adhesive.  Use a driver to remove these two screws (a magnet is your friend so not to lose them) this should break the bond between the magnet structure and resonator.  Then very firmly grip the resonator at the base near the solder terminals.  Be careful not to sever lead wires to the coil.  The resonator will come straight off by pulling forward.

 

[mindlessstudio]

Thanks guys, I managed to get the black plastic cap off without any problems now. I'm not quite sure what to look for re the diaphragm, though. Attaching some photos – it looks fine to my little eye. There's a slight dent in the 'ring' part and the center part seems to be slightly 'ovally' glued on, but the dent shouldn't make it not-work and the oval bit would have manifested itself forever, yeah?

 

[mindlessstudio]

Not related to the capsule problem, but see what the filter looks like!!! I've got a hunch that a drummer hit this mic pretty hard (it was being used alongside two brethren for toms when it stopped working. Sigh). But that hasn't got anything to do with the other problem, given that the capsule doesn't output anything meaningful even from directly out of the diaphragm, yeah?

Need to work out how the PCB should have been hooked up and then do a bodge job. Bummer. Only bit I haven't worked out yet is that little black cable out of the transformer.  Any ideas?

 

[mindlessstudio]

The other side of the PCB