Reassembled with clean board. Yes, after soldering everything back I cleaned up again with more IPA .
Unbelievable, everything works.
Tested fig 8, omni, front and back as all the other functions.
Listen to the attached file if you want to rejoy with me.
I do not bother with a frequency analysis. Now It sound like a NT2-A for me.
Still a little low output for my taste but now I can use it, I don't dig further in this tagic-comic hole.
TO ALL AUDIOPHOOL OUT THERE: IF YOU PAINT IT BLACK IT DOES NOT SOUND BETTER! IF IT DOES IT IS YOUR FUNNY BRAIN NOT THE IMPROVED CIRCUIT/SIGNAL!![](https://imgs.xkcd.com/comics/audiophiles.png)
Failure analysis:
Mic was stored somewhere for a long time and ended up in Ebay. Few minutes after powering up the mic, the 80VDC broke off the black no-sense dielectric and created a resistance path in the input stage.
Thanks to everybody who helped me!