How to repair a Blue, Bluebird Microphone (The Head snapped off)

[niceties55]

I got a free Bluebird Microphone from a friend, however the head has snapped off and the wires are broken that connect the microphone to the electronics inside of the body. (See Photo)

I was wondering if anyone had any tips and tricks to fix this neat mic? It would be great to have if I can get it up and running.

I have beginner/intermediate soldering skills, so I am willing to take it apart and work on it.

[Wonks]

It looks rather like the head’s snapped off before. There looks to be quite a lot of existing glue around the join area.

Hard to say if the black insert is plastic or metal, but it’s probably in there for good.

Which may make any attempt at a repair very difficult.

I’d have a go at undoing the small metal screws around the solid band and see if you can remove the grille and the capsule. It may be possible to drill out the insert and re-tap a thread, though there doesn’t appear to be much thread left on the body section to connect to. If you can get the capsule out, then you should be able to rewire it, and then the top might have to be stuck on with epoxy. Not pretty, but you could have a working mic.

But you need to get it all apart first.

[Sam Spoons]

I'd be looking at dismantling both parts so that you could drill out the bottom part with the broken male thread and remove the broken part from the top section without risking damage to the electronics then I'd tap the bottom with a matching thread so you could use a piece of threaded brass rod to re-join the two parts. The neat way to reinstate the wiring would be to drill the threaded rod (easy enough if you have a lathe, doable with a pillar drill but tricky with a hand held drill) but a couple of holes to the side of the new fixing to thread a piece of FST through would get you working and not look too Heath-Robinson.

[Drew Stephenson]

I'd be looking at dismantling both parts so that you could drill out the bottom part with the broken male thread and remove the broken part from the top section without risking damage to the electronics then I'd tap the bottom with a matching thread so you could use a piece of threaded brass rod to re-join the two parts. The neat way to reinstate the wiring would be to drill the threaded rod (easy enough if you have a lathe, doable with a pillar drill but tricky with a hand held drill) but a couple of holes to the side of the new fixing to thread a piece of FST through would get you working and not look too Heath-Robinson.

I'd probably take this approach if it were mine. Not having a pillar drill I'd accept the compromise of a bit of external wiring to connect the basket to the body.

[Wonks]

Though you could thread some brass tube instead.

External leads will be more prone to pick up noise, especially as it will be before the mic’s own preamp, so any noise will be boosted, so I think you’d still want the leads to run within shielding.

You might be able to run the cables separately in an extra metal tube (or tubes) added to run from the head to the body. Maybe one either side of the central post so it looks balanced. Could give some extra support to the head as well.

But you’ll need to open everything up first and see what’s possible. There may be circuitry or equipment in the way of any alternative cable routes. Also check for any internal casing cracks that might cause issues. Unlikely I know, but the mic may have been dropped several times.

[Hugh Robjohns]

The leads from the capsule are operating in an ultra-high impedance environment so need very careful shielding.

The head on that mic is actually mounted via a rubber grommet which provides some shock mounting. How essential that is I can't say, but Blue wouldn't have used it if they didn't think it worthwhile.

I get the interest in trying to get a free mic working again... but it has clearly been seriously abused in its former life and you could well find that the capsule itself has been damaged through percussive shock (a common capacitor capsule killer!) or the circuitry within the body could be cracked and damaged.

Also, where the capsule wires connect to the circuit board there is likely to be some form of sealant on the PCB terminals and components protecting the ultra-high impedance end of the head amp from moisture. That will need to be carefully removed to attach new wires and replaced to avoid unwanted hiss and noise in use.