Tuesday, May 31, 2011

Green Bullet Repair

Soldering iron with high wattage button on the side, electrical solder, flux, damp sponge, de-soldering braid.
My green bullet microphone was having some problems cutting out when I would move the cord so I thought I would try to repair it.  I searched the internet for a while but could not find very much information on repairing green bullet mics.  I suspected there was something wrong with the cable near the spring because when I moved that part of the cable it sometimes caused the mic to make a loud click or cut out.

Used an allen wrench to remove the set screw on the cable and used a screwdriver to remove the two small screws on the screen on the front of the mic.
The mic has a rubber seal around the transducer element.  I didn't see any problem with that part.
Here is a close-up of the transducer element.  I had originally thought that maybe some wires had worn through their insulation and it was making contact with the case of the mic but I could not see any evidence of that.  The wires, solder joints and heat shrink all seemed intact.
I then disassembled the cable with the spring.  This was interesting.  A bit of copper braid is soldered to the top of the spring that is then forced into the opening and held in place with a set screw.  I still could not see anything wrong and since it is soldered in place I had to use some copper braid to de-solder it.
Once I got it de-soldered I found another interesting feature.  the braid had broken from the solder point.  I suspected this is what was causing the problem.
I decided I needed to attach a conductor from the braid near the spring to the braid near the mic case.  It seemed too short to reach this distance.  I first tried some fine wire but that didn't seem to work.  I then tried a short piece of desoldering braid.  I thought this might work perfectly.  So I tinned it by heating the braid and coating it with solder.  Then I soldered it into place on the mic cable.
Put the spring back into place and screwed the set screw back.  So far this repair has been successful.  The cut out is gone and the mic seems to work fine.

For a bit of the history behind the green bullet visit:

I have been gigging with this repair for several months now and it still works great.

Update: Patching this with de-solder braid is not the best way to do this.  This eventually did fail.  Better to redo this with the shielding mesh.

Blog out,
Hans Mikelson
Plasma Portal


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