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PostPosted: Tue Jul 01, 2014 5:37 pm 
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Joined: Wed Jul 17, 2013 6:50 pm
Posts: 8
Hello there,

I'm having problem with one of my 587 :( recently I switched OFF and then back ON the electricity at home. When I switched it ON the audio interface sent a very loud noise to the philips. One of it unfortunately now has a problem.
When this 587 is switched on ( even without music ) it produces a constant noise like wind that comes ONLY from the woofer. It works, it sounds great for around 30 min and then this noise constantly in the background. It is not a damaged woofer, it does this noise even without signal, without woofer excursions.

SOME COSIDERATIONS:

This 587 was recently ( one month ago ) recaped and it was working just fine until that accident.
I cleaned all the PCBs before assemble back the pieces.
When changed the caps with new ones I accidentally inverted the polarity of one capacitor and when I tested the speaker the cap started smoking a bit.
I inverted this capacitor to the correct polarity and the speaker worked fine, hours and days of test with no problems until that accident I recently had with the electricity.

May it be this capacitor I wrongly inverted got partially damaged and after that problem with the electricity it went broken?
This capacitor is the 2245 placed on the right side of those big caps 2247 and 2243 on the amplifier PCB.

VERY IMPORTANT:
Consider that the speaker works just fine for let's say 30 min and then does that problem. The windy noise on the woofer.
Another consideration is that the noise comes ONLY from the woofer. Mid and Tweeter is not affect by it


Caps? Probably but don't know which one is damaged ( the 2245 is just my guess based on what happened when I recaped this speaker ). Do you have any idea where I have to look for? It would be great to identify the caps that are related to the woofer.

Hope you can help me.

Best,
Andrea


Last edited by freakmfb on Thu Jul 03, 2014 2:11 am, edited 3 times in total.

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PostPosted: Wed Jul 02, 2014 9:52 pm 
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Joined: Wed Jul 17, 2013 6:50 pm
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No idea?


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PostPosted: Wed Jul 02, 2014 11:17 pm 
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Rank: 22RH545

Joined: Fri Feb 11, 2005 11:02 am
Posts: 2030
Hi Anrea,

The first thing to try would be exchanging the two amplifiers and see if the problem moves with the amplifier.

Probably some good dust cleaning on the small transistors-leads will help.
Take a small brush to clean between the leads of the small transistors.

Success !

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Herman:
Voor je het weet weet je het niet meer !


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PostPosted: Wed Jul 02, 2014 11:21 pm 
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Joined: Wed Jul 17, 2013 6:50 pm
Posts: 8
herman wrote:
Hi Anrea,

The first thing to try would be exchanging the two amplifiers and see if the problem moves with the amplifier.

Probably some good dust cleaning on the small transistors-leads will help.
Take a small brush to clean between the leads of the small transistors.

Success !


Hi Herman,

thanks for your reply. In fact this 587 was recently ( one month ago ) recaped and it was working fine until that accident and I cleaned all the PCBs before assemble back the pieces.
I have to admit that when I assembled this speaker I accidentally inverted the polarity of one capacitor and when I tested the speaker the cap started smoking a bit.
I inverted this capacitor to the correct polarity and the speaker worked fine until that accident I recently had with the electricity.
May it be this capacitor I wrongly inverted got partially damaged and after that problem it went broken?

This capacitor is the 2245 right side to those big one 2247 and 2243 on the amplifier PCB.

VERY IMPORTANT:
Consider that the speaker works just fine for let's say 30 min and then does that problem. The windy noise.
Another consideration is that the noise comes only from the woofer. Mid and Tweeter is not affect by it


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PostPosted: Sat Jul 05, 2014 10:40 pm 
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Rank: 22RH545

Joined: Fri Feb 11, 2005 11:02 am
Posts: 2030
Hi Andrea,

I considered your points before my previous posting.
Have you had a chance to change the amplifier boards yet ?
The problem could come from the woofer itself. Otherwise I stick to my suggestion of cleaning those small transistors.
(have a good look at their pins before cleaning)

_________________
Herman:
Voor je het weet weet je het niet meer !


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