Neumann M149 - Problems - Sound cuts out

[Whoops]

Hello,
I have a Neumann M149 microphone which started to cut the sound when singing into it.
The cable had a dodgy connector which was replaced, and the cable carefully re-soldered at both ends and tested.
The PSU was also tested when connected to the microphone and all the voltages are perfectly up to spec.

I did a sound sample that I'm attaching to this post showing the problem of the microphone.
Could you please have a listen and let me know what you think the problem might be?

Thank you so much

 

[moamps]

Does this dropout also occur at lower sound pressures? If not, then it sounds like a standard problem with a dirty or insufficiently tightened capsule membrane that touches the backplate due to higher sound pressure. After that contact, it takes some time for the membrane to charge again and start giving a signal. Have you tried the other side of the capsule in figure eight setting?

 

[Whoops]

Does this dropout also occur at lower sound pressures?

it doesn’t happen at lower

If not, then it sounds like a standard problem with a dirty or insufficiently tightened capsule membrane

visually the capsule is clean, there’s no dirty or debris in the capsule. It’s pretty clean

maybe the membrane is not tight enough

Have you tried the other side of the capsule in figure eight setting?

No, I haven’t done that, but will try that out

 

[nielsk]

You can also swap the front & rear capsule leads, as I recall this is single backplate.
If the backside is good you can rotate the capsule and should be able to use the front in cardioid, this has the multipattern on it but this it may not cause any problem with the switch set to uni
Maybe get some more use before re-skin/ replace

 

[Whoops]

I cleaned the capsule very very carefully with a light brush and distilled water.
Let it dry well and the mic is working perfectly again.
Stable with no sound drop outs.

It seems the capsule was contaminated which made it being moisture sensitive,
cleaning it solved the issue