Question about Alesis M1-Active MkII Main / Stereo Speaker

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Alesis M1 Active 620 - Power supply broke down

Hi,
I have a pair of speakers Alesis M1 Active 620 and one time when i plug the power cord i listened a "clap" inside the speaker and it didn't work since there. I opened the speaker and after test the power supply it didn't had power on the output. I changed two transistors FET (IRF 840), two resistores of 39Kohm 2W and one zenner 20Volts (1N4747). It still not working! I think that the circuitry of oscilator is not working because i opened the other speaker which is good and on the same terminals of the same transistors IRF 840 the good speaker has an oscillating signal!

I don't know what can I do, can anyone help me? Where can I buy a new power supply board for replace this???

Please help me, I need the speakers for work!


Thanks all a lot, best regards.
Pedro Madeira, from Portugal (email: djholtz@sapo.pt)

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5 Suggested Answers

  • 15 Answers

SOURCE: Alesis M1 Active Mk2 Speaker won't Power Up

Hi, This is usually the Capacitor C8 on the powerboard it usually bulges and pops, its becuase its right next to a resistor which gets very hot and sometimes puts the capacitor into meltdown, yours might have gone past that stage but this is worth a look; http://www.neufeld.newton.ks.us/electronics/?p=232

Hope this helps

Cheers

Steve

Posted on Jun 02, 2009

r_ic7
  • 13 Answers

SOURCE: Fried Woofer

The problem are worsen that before. It is wisely to replace both left and right amplifier
IC, but make ensure that the power supply feed a good amount of voltage to amplifier,
Also a strong good signal. Be sure to measure it.

r_ic7

Posted on Nov 29, 2008

  • 1 Answer

SOURCE: Alesis M1 ACTIVE MONITOR amp circuitry board is ticking

Had the blue light flicker of death. Fixed this issue with a 330uF 35V cap. Sounds just fabulous now. I did get the cap out of the radiant spell of the resistor utilizing the longer leads and insulator for the leads. I had 2 months left in my warranty but figured paying for shipping to Alesis and at least 2 weeks wait just didn't compare to the $2 I spent with a local electronics shop.
Downtime=<2 hours.
Kudos folks. I've been unemployed for 6 months after a layoff and was really bummed until I found this site.

Posted on Mar 13, 2009

  • 15 Answers

SOURCE: alesis 620 m1 active studio monitors sound cutting out

It could be a power problem, unless you have blown the driver ?, carefully pull out the power supply board, and look to see if anything looks melted, burned, or capacitors popped etc. Be carefull though as I do not want to be responsible if you get an electric shock, etc. preferably look and dont touch, just use common sense ;)

Posted on Jun 02, 2009

  • 1 Answer

SOURCE: my alesis m1 active 620 monitors blue lite keeps

Thanks for following up...I took it to get fixed..$150.00 later it works..

Posted on Oct 08, 2009

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