Recently purchased a original u87 with Tuchel 7 Pin connector. It was connected to a tech built phantom box via 5 pin plug.
All sounded great, however I wanted change this to an xlr and use my mic pre's to power the mic.
from my research and looking at the circuit diagram I connected the following from the Tuchel connector
Pin 1 to pin 2 XLR
Pin 2 to Pin 3 XLR
Pins 3 and 7 to Pin 1 XLR
However the mic no longer o/p audio.
On opening the mic I saw a connection from the + battery terminals to R22, which looks like a mod to me, because with this wire in place you would not be able to use a battery. Please see pictures, can any one tell me if this is factory wiring and if you can shed some light on this that would be great.