Speaker scratchy bzzzzzz on my M90

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blu_fuz

blu_fuz

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I have had my M90 for a few years now, never heard anything strange. It is never really cranked even to 1/2 way and is usually playing streaming internet through the RCA line-in at 'office volume' so I can still talk on the phone/employees.


Friday the M90 sounded fine (and everyday before that). Come Monday I noticed the left VU wasn't moving and no sound from the left speaker. I figured out that the line-in/phono switch wasn't making contact and was cutting out the left channel. Fiddled with it and the left VU started swinging and sound was back.

Strange thing is now the left speaker is making a scratchy noise with the bass notes of anything I play through it. Almost like if the voice coil is f'd up from playing it too loud and might be kind of blown. If I play it louder, you can still faintly hear this scratchy bzzz but it is drowned out more because the music is louder but it is still there.


I thought maybe the switches are not making contact or the headphone jack is dirty. I flipped some switches hoping for a quick fix. Didn't make a change.


Right channel is clear.

I plugged in headphones and the sound clear, no scratchy noise.


Can a speaker just 'blow' from age even if the surrounds are good? If the coil is bad for some reason, is there hope for the speaker to be fixed/used?
 
floyd

floyd

Boomus Fidelis
joe my m90 does the same thing sometimes , usually a good cleaning fixes it up but lately its been getting worse , usually i just push in the band selector switches and fiddle with the toggle switches and it clears it up.
 
blu_fuz

blu_fuz

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JVC Floyd said:
joe my m90 does the same thing sometimes , usually a good cleaning fixes it up but lately its been getting worse , usually i just push in the band selector switches and fiddle with the toggle switches and it clears it up.
Click to expand...

^ I thought that would help mine too but it didn't make it better :sad:
 
blu_fuz

blu_fuz

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I was reading that maybe the voice coil wire adhesive let go of one of the coils and it is rubbing on the magnet. Maybe the speaker basket is tweeked and I should try re-mounting the basket using a X pattern when I install the screws. Or possibly the speaker cone is sagging and simply rotating the speaker could keep the coil from rubbing in the magnet.
 
baddboybill

baddboybill

Boomus Fidelis
I would try what Norm recommended with swapping speakers to see difference and I agree with him about the switch.


Sent from my iPad using Tapatalk
 
Beosystem10

Beosystem10

Member (SA)
skippy1969 said:
Sounds like a bad woofer to me too,especially if it sounds ok with headphones. :cool:
Click to expand...
Possible, but the headphones take their feed from IC601, a chip dedicated to headphone duty, where the speakers are driven by (final A/F), IC301, the power amp.
 
floyd

floyd

Boomus Fidelis
joe there is a way to remove the original m90 woofer cone and overlap it onto a different woofer frame that already has the voice coil.its a total and complete pain to do ,but you would never know the difference appearance wise.
 
blu_fuz

blu_fuz

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Staff member
Skip stopped over and gave me some Crown SZ5100 white speakers and Cpl-Chronic sent me a set of M90 woofs.

Thanks guys.

woofs.jpg
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Still waiting to see if the M90 woofers did the trick & glad we could trade woofs for straps....

I always love me some BLU-FUZ straps...

Cpl
 
blu_fuz

blu_fuz

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Staff member
Just got back from vacation. Its busy here with our kitchen remodel so it will be awhile until I can get to it. Thanks again!
 
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