troubleshooting U87ai with a problem

[ward]

Hi,  I have a U87ai with a problem.
I made a small sound file of what the problem sounds like ...
https://www.dropbox.com/s/yyl6u8h5hb9byxr/distortion%20broken%2087ai_1.aif?dl=0
Sometimes it disappears for a time, but then it comes back again.... and it stays in this +-5seconds pattern.
I hope somebody here knows how I can solve this?

Thanks,
Ward

 

[ward]

I have taken off the bottom and cover and looked at it.  Wiggled the head basket softly and then I put it back together.
This simple action seems to have solved the problem ?
At least I haven't heard it for at least an hour now...

So I'm thinking it's the pins connecting headbasket that gave an intermittent contact.
Should I clean these pins and how do I get to them without breaking something ?
I just wish I could believe it's not gonna happen during the next recording session...

 

[Bo Deadly]

Could be some oxidation on the shell. Maybe put a little deoxit on a rag and clean the threaded parts of the shell that contact each other.

 

[mjrippe]

I have taken off the bottom and cover and looked at it.  Wiggled the head basket softly and then I put it back together.
This simple action seems to have solved the problem ?
At least I haven't heard it for at least an hour now...

So I'm thinking it's the pins connecting headbasket that gave an intermittent contact.
Should I clean these pins and how do I get to them without breaking something ?
I just wish I could believe it's not gonna happen during the next recording session...

The pins connecting the headbasket are gold plated.  Gold does not form an oxide layer (tarnish) so as long as nobody has roughed them up they should be fine.  As Squarewave mentioned, the mic body needs to make good contact all around - this is your shielding/ground.

 

[moamps]

Headbasket pins of U87 should be cleaned periodically using alcohol. Namely, the high voltage for the polarization of the capsule can attract various impurities at the junction of the contacts and make one type of diode that can cause interference like the one that happened to you.

Female pins on the body should be slightly tightened on older microphones using such a metal needle.

 

[Moby]

Hi,  I have a U87ai with a problem.
I made a small sound file of what the problem sounds like ...
https://www.dropbox.com/s/yyl6u8h5hb9byxr/distortion%20broken%2087ai_1.aif?dl=0
Sometimes it disappears for a time, but then it comes back again.... and it stays in this +-5seconds pattern.
I hope somebody here knows how I can solve this?

Thanks,
Ward

How it handle "voice pops" ? To me it sounds like a capsule lost it's tension but maybe I'm wrong. Also, moisture in capsule can make this happen .

 

[ward]

Thanks for listening and giving advice people 
After my previous post the problem came back after some time...

So, now I cleaned the pins with alcohol, and tensioned the female connectors with a jewellers screwdriver.
And so far it behaves ... I'll have to listen for some more time....

How it handle "voice pops" ? To me it sounds like a capsule lost it's tension but maybe I'm wrong. Also, moisture in capsule can make this happen .

I made a little recording of me talking directly into the problematic U87ai, and then in a good one.
Not very scientific, I don't think I have the distance and direction exactly the same.
There is a difference in handling pops.
https://www.dropbox.com/s/fmoannq6cl61hp5/BAD%20poppp%2087ai.aif?dl=0
https://www.dropbox.com/s/jimz3n9ammklqgk/GOOD%20poppp%2087ai_1.aif?dl=0

Please ignore the test above, it made it at least a little more scientific by talking into both at the same time.
Switches are the same, preamp is the same with the same gainsetting.
https://www.dropbox.com/s/3t90hcbx0j6zmy6/BAD%2087ai.aif?dl=0
https://www.dropbox.com/s/aayrkjh75gweahx/GOOD%2087ai.aif?dl=0

 

[RuudNL]

The most important difference is the level between the two recordings.

 

[Whoops]

How it handle "voice pops" ? To me it sounds like a capsule lost it's tension but maybe I'm wrong. Also, moisture in capsule can make this happen .

+1