Topic: Electret cap restoration

[ts]

I previously owned a pair of AKG Ck2x caps that were completely dead. With the help of another board member we (he) convinced Karl from AKG Austria that these were worth working on. Karl did reluctantly do it and they have been fine ever since. Well I don't own them anymore but I'm pretty sure they still work

I now have a line on a pair of Nakamichi CM700 caps that seem to have suffered the same fate. These are not completely dead. They have a weak signal with some static. Can these, like the AKG's, be brought back to life? Stephen Sank has already declined to look at them and does not know of anyone who would. I have also sent emails to Tracy Korby, Richard, Busman and Chris Church. Anyone else who may be willing to tinker with these?

on second thought, maybe the power supply is at fault?

[bugg100]

Well, you hit all the high points of gear techs here....  Do you mean to say you have a pair of Nak 300's that don't seem to work OR caps that you know don't work?  Much more to these mics than just the caps....

[illconditioned]

Would have to test the caps alone to be sure.  If the electret charge is missing (or if the diaphragm is damaged) I don't think there is anything to do.  I don't know how fragile the backplate charge is, but I remember Karl @ AKG service telling me that it could be lost/damaged if you mess with the backplate when you have the capsules open.  I was rewiring CK9x series capsules to run on battery power.

  Richard

[ts]

Would have to test the caps alone to be sure.  If the electret charge is missing (or if the diaphragm is damaged) I don't think there is anything to do.  I don't know how fragile the backplate charge is, but I remember Karl @ AKG service telling me that it could be lost/damaged if you mess with the backplate when you have the capsules open.  I was rewiring CK9x series capsules to run on battery power.

  Richard

Thanks Richard. I should have them by Monday. I will contact you then.

Tony

[Church-Audio]

Would have to test the caps alone to be sure.  If the electret charge is missing (or if the diaphragm is damaged) I don't think there is anything to do.  I don't know how fragile the backplate charge is, but I remember Karl @ AKG service telling me that it could be lost/damaged if you mess with the backplate when you have the capsules open.  I was rewiring CK9x series capsules to run on battery power.

  Richard

Thanks Richard. I should have them by Monday. I will contact you then.

Tony

With most capsules the problem of losing power is often one of a shorted out capsule where metal debris shorts out the diaphragm to ground. Or to the back plate. In some cases I can open up the mic capsule and remove the conductive particles using a microscope and a set of very fine brushes and compressed filtered air. Its not an easy task and there are absolutely no guarantees. If your lucky its just a set of fet transistors that have gone bad but it sounds like this is just a capsule with no electronics in it.

[illconditioned]

Would have to test the caps alone to be sure.  If the electret charge is missing (or if the diaphragm is damaged) I don't think there is anything to do.  I don't know how fragile the backplate charge is, but I remember Karl @ AKG service telling me that it could be lost/damaged if you mess with the backplate when you have the capsules open.  I was rewiring CK9x series capsules to run on battery power.

  Richard

Thanks Richard. I should have them by Monday. I will contact you then.

Tony

Note: I'm not offering to fix these!  I'm just offering information.  I've given up fixing gear for others.  I worry that I may break more than I fix!!!

Talk to Chris Church or perhaps Busman...

  Richard