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Beolab 2 distorted diaphragm

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jbarhydt
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jbarhydt posted on Thu, Oct 17 2019 1:09 AM

I recently purchased a used Beolab 2 (BL2) to compliment a set of Beolab 1 speakers that I purchased earlier in the year.  The box and packing that the BL2 came in were not sturdy enough to protect the sub, so I suspect that the sub bounced around during shipping.  When I unpacked the sub, I noticed a "clanking" noise coming from inside the chassis.  I also noticed that the outer diaphragm was "tilted" in one direction, and as I rotated the sub, the "tilting" of the diaphragm would change shape.

I downloaded the service manual and noted that B&O states that there is a mechanical limit to the driver, and I'm wondering if during shipping, the sub was dropped in such a way that the voice-coil in the driver exceeded the "mechanical limit" and was damaged.  Other than the exploded parts diagram, I don't know what the driver looks like, but if it is like other speaker drivers that I've had in the past, the distortion of the diaphragm/grill is most likely due to a broken voice-coil.

I connected the BL2 to my existing system and the red light came on with the power leads, and then the green light came on for a second when I turned the system on, only to go back to red.

I'm thinking that the driver is physically broken.

Question 1:  If I pull out the driver, can I see visually if the voice coil is dislocated/broken?

Question 2:  Can I use my ohm meter on the driver contacts to verity that the voice coil is still attached or not?

 

Thanks.

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Beobuddy
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Utrecht, The Netherlands
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Beobuddy replied on Thu, Oct 17 2019 10:05 AM

I fixed several with a broken magnet at the back.

The magnet is huge and it is possible that it breaks in halve. When that happens, the ntc (small wire with temperture probe) probably becomes loose.

Without the ntc the BL7-2 doesn't start up.

So, start dismanteling both side parts and you can have a look at the driver's back with its magnet. 

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