The Sennheiser freePORT radio microphone was a very popular vocal mic, being inexpensive and good quality. It is very much at the budget end of the Sennheiser range and doesn’t have all the fancy features of the more expensive models but still does a solid job.
We have a couple of these at our church which we use for portable use and they get quite a lot of abuse. One of them recently broke so I had a look at it, always being keen to repair rather than replace. The handset had got bashed and there was no audio coming through.
One difficulty with these mics is that it’s not obvious how to get into them. The best place to start it by unscrewing the top of the handset to expose the capsule:
The problem here is pretty obvious, in that one of (very thin) wires which runs from the capsule into the body of the mic has broken off. So a repair should be a simple matter of resoldering it, although there is no slack available here so the whole wire needs to be replaced.
The next thing to do is to remove a screw in the battery compartment, and the collar at the top which fits on to the pop shield:
Then you have to remove the shiny black plastic piece which says ‘Sennheiser Freeport’ and covers the electronics. This is much easier if you remove the collar as well:
I ended up replacing both of the wires on the right hand side of the picture by desoldering them from the board and replacing them with new. The wires are very fine, and I used two cores from a burglar alarm cable which were the thinnest thing I could find. You have to thread them through the collar to get to the capsule. The black wire goes to the pad marked with a blue dot on the capsule. Once done it’s a fairly simple matter of putting it all back together again.
The other problem I have had with these mics is that the power connector on the receiver tends to get worn out. This is also dead easy to replace. So with relatively little effort you can keep this working in spite of some quite rough handling.