Bought a Philips rarity that doesn't work - any ideas?

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WhinyLittleRunt

WhinyLittleRunt

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So I bought a Philips LBB-9020 that I have been seeking out for some time now, for no good reason other than it looks cool and it's rare. I will say that, before I continue, the seller has more of the same that I can swap the non-working one for, which I will be doing, but I'm just really wondering what would make this mic not work.

It has a big on-off switch on the front, and a bass roll-off switch down at the bottom. Supposedly up is for voice, and down is for music. Anyway, I got it in the mail the other day and I was all psyched. The thing has a Tuchel connector on it, so there was an adapter cable with it. Ok, no big deal. I expected that. Plug it in, nothing. No signal at all. Ok. Well, maybe it's the connector cable. Well, I grabbed a probe and got signal from each of the terminals, so I don't think it's that. I get some alligator clips and stuff and try to bypass the connector entirely right to the pins on my mixer. Still nothing. Ok, well then the cable is probably fine. I decided to have a look inside and see if something broke. I figured out how to get it open and apart (had to desolder the terminals at the bottom) and the plastic sleeve slides off. Inside, I see nothing much; the mic capsule itself, and a little PCB with nothing on it but what looks like a resistor, the on/off switch, bass roll-off slide switch, and this weird circular thing:



So I tried to bypass the board entirely and alligator clip just where the two wires come off the capsule. Still get nothing.



At this point I'm guessing to myself that the capsule is shot. But that would be odd for it to break in shipping, as well packed as it was. And it was supposedly tested beforehand. Now, like I said I can send it back and get another one that works. But because the mic has almost nothing inside it I'm baffled as to what could cause it to not pass any signal. I probed the PCB with my DMM and got signal passthrough at all points, and when I had it all back together again I plugged it in and when you flip the on/off switch, you can hear the click but again no signal.

Any ideas as to what the circular thing is on the board, and also if a capsule can just go bad? I'm more curious than anything else because I've never had a defective mic...
 
Yes, capsules certainly can and do go bad The round thing looks like an inductor for the filter circuit.

>So I tried to bypass the board entirely and alligator clip just where the two wires come off the capsule. Still get nothing.

Did you unsolder the red and blue wires so that it is completely isolated from the little circuit board? I think that is what you have done. No signal? Bad capsule!

Is it a high or low impedance mic? My only thought was that if you are plugging a hi-Z mic into a low-Z input (or vice versa) you may get little output. Otherwise it sounds like you have done all the tests and time to swap the mic.

Cheers
Stewart
 
Yes, I isolated the red and blue directly off the capsule and got nothing. Cool - i didn't think there was much more to it. Hopefully this next one will work right, as I'm a little more than bummed any time I get anything defective in the mail...
 
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