Help needed - Why is it only working in Omni?

[narcolepzzz]

Newbie here. I'm trying to drop a JLI-86u into a takstar tak55. At first it was working fine. Then it was horribly noisy in cardioid and fig8, but fine in Omni. The pattern switch soon stopped doing anything. Is there a likely issue here, and how do I test for it?

I felt like there was a bad ground joint, so I re-did that, but nothing changed. Could I have permanently ruined the capsule by using it while poorly grounded?

 

[micolas]

Newbie here. I'm trying to drop a JLI-86u into a takstar tak55. At first it was working fine. Then it was horribly noisy in cardioid and fig8, but fine in Omni. The pattern switch soon stopped doing anything. Is there a likely issue here, and how do I test for it?

I felt like there was a bad ground joint, so I re-did that, but nothing changed. Could I have permanently ruined the capsule by using it while poorly grounded?

It would be very useful to post some relevant pictures with good resolution.
As a general rule, before modifying anything you must take detailed pictures of the stock, original product.

 

[RuudNL]

Sometimes this happens when the screws in the tensioning rings on both sides accidentally touch each other.
(It happened to me once.)

 

[micolas]

Sometimes this happens when the screws in the tensioning rings on both sides accidentally touch each other.
(It happened to me once.)

That would mean that even with the switch in the cardioid position, the microphone should still sound omni.

 

[Khron]

Some related thoughts..?

https://groupdiy.com/threads/why-you-should-never-use-multi-pattern-mics.81157/

(Not sure which page it's on, but there's mention of the rear diaphragm being left floating with no discharge path, when switching from omni or fig-8 back to cardioid...)

 

[narcolepzzz]

Sometimes this happens when the screws in the tensioning rings on both sides accidentally touch each other.
(It happened to me once.)

This was it. Thanks!

For anyone wondering, JLI support was excellent. They responded in under two hours and are sending a replacement.

 

[micolas]

This was it. Thanks!

For anyone wondering, JLI support was excellent. They responded in under two hours and are sending a replacement.

Excellent!
Did you measure with DMM between the two diaphragms, what does it indicate, short circuit or a small variable resistance?
Did you return the capsule?
If not, you can fix it.

 

[narcolepzzz]

Excellent!
Did you measure with DMM between the two diaphragms, what does it indicate, short circuit or a small variable resistance?
Did you return the capsule?
If not, you can fix it.

Honest question, how is a small resistance different than a short in this context? How would each show up on the dmm?

They haven't asked for it back, so fixing it is definitely on the table. Any resources and tools you'd recommend before I try?

 

[micolas]

In short: a variable resistance is different from a permanent short circuit. It seems that you are in the second case.
Did you also measure the resistance between the blue wires from the backplate and between them and the white ones from the diaphragms?