Mistery Tube mic!! Need help to fix

[soundlaboratory]

I have had this mic for a few years now and i have never been able to find any information on it. as to make, specs etc.. The mic and PSU both read CSD custom sound designs.
the mic sounds just beautiful on most things often beating out a vintage u87 and a u67.

But as of late it has been acting up.

1. About half of the time when i power up the mic in cardioid setting. The BACK capsule becomes the cardioid one meaning the mic is 180 degrees flipped it sounds fine but i have to turn the mic around

2. when set to omni it goes silent no buzzes no anything just silent

3. when set to fig8 it acts just the same as #1 no difference


The mic i believe is worth me fixing but i have no idea where to send it, it has a 6201 tube in it and that's how i got it, it uses a 7 pin xlr between mic and psu.

some pics attached
Anyone recognize either this mic or the symptoms im having?
im leaning towards a bad switch its a 9 position

[digitaldrummer]

don't know anything about the mic, but have you tried spraying some cleaner (deoxit or other) on the switch? or if the switch is on the PSU, maybe the cable is faulty? you should be able to test that with an ohmeter.

Mike

[soundlaboratory]

The switch is indeed in the PSU and seems to be all sealed up and no access to the contact points, And yes i've tried 2 different cables same results.

[infiniteposse]

I would recommend posting this at the PSW forums, perhaps in Klaus H's sub-forum. Those guys know their mics.

Good luck!

[rhythm ranch]

Apparently CSD is a sound installation company specializing in churches. They must have gotten some mics rebranded at some point. Their webpage is here. Might be worth contacting them to see if they still have any info.

[Nick Sevilla]

This sounds to me like one of three things :

1.- Power is not getting to one of the capsules, namely the front capsule. Check those capacitors (the 6 black thingies in the mic) for leakage / bad capacitor. Those tend to fail at around 5 years of age.

2.- A bad connection to the front capsule. check all the wiring to and from the front capsule. measure continuity AND resistance, and make sure ti matches the known working capsule side too.

3.- A bad front capsule. Again, check for continuity, a bad capsule membrane / damage to the capsule, etc...

Cheers

[rodabod]

Check the polarisation voltage feeding the front diaphragm. You may need to check back to the PSU where it is derived (IIRC) Circuit is probably a Nady 1050 or something similar. Schematics are around.

[themagicmanmdt]

This sounds to me like one of three things :

1.- Power is not getting to one of the capsules, namely the front capsule. Check those capacitors (the 6 black thingies in the mic) for leakage / bad capacitor. Those tend to fail at around 5 years of age.

2.- A bad connection to the front capsule. check all the wiring to and from the front capsule. measure continuity AND resistance, and make sure ti matches the known working capsule side too.

3.- A bad front capsule. Again, check for continuity, a bad capsule membrane / damage to the capsule, etc...

Cheers