melted lm3886tf in my Event ASP8 monitors PLEASE HELP!!! - diyAudio
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Old 22nd November 2012, 01:56 PM   #1
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Default melted lm3886tf in my Event ASP8 monitors PLEASE HELP!!!

Hey guys i realy hope someone can help me out here. I have a pair of Event ASP8 studio monitors that werd made in 2005 and one of them stopped working out of the blue recently. These speakers are self powered with 300 watt built in amplifiers. I opened it up and the only thing i could notice wrong was one of the 4 op amps marked LM3886TF was burnt. It is actualy cracked down the middle and the contacts are black and melted. All of the surface mount resistors and the capacitors appear to b perfect the only other thing i noticed was there was very very little thermal pasteon the op amps and the heatsink and what is there is dried up. These speakers get very hot to the point of not being able to touch them so is it possible that improper heat dispertion fried the op amp or is there something else going on here. I ordered a new op amp and if i replace it do i run the risk of having it burn up again right away? Or should it b ok if i reapply thermal paste considerably on everything that needs it? Basicaly im wondering what could cause this to happen and should i b ok by jus replacing the op amp wich is the only burnt component on the board. Any help would realy b appreciated this is my first post and i am a self taught electronics fixer but my track record has been pretty good so far with what i have repaired so i would love as much information on this as possible. Thanks again to anyone who choses to help me out!
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Old 22nd November 2012, 02:13 PM   #2
AndrewT is offline AndrewT  Scotland
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one paragraph !
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regards Andrew T.
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Old 22nd November 2012, 02:26 PM   #3
CJ900RR is offline CJ900RR  Sweden
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Hi!

As Andrew tries to say I guess, divide your text in to smaller pieces so it will be more easy to read.

Anyway, here is a link to the schematic: Event ASP8 Service manual

For start, which one of the LM3886 is broken?
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Old 22nd November 2012, 02:50 PM   #4
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Thanks for replying. It is the first op amp on the bottom that is associated with the highs. The speaker turns on as in the power led operates but there is no sound at all.
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Old 22nd November 2012, 02:57 PM   #5
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Thank you for the download. Any and all information on this topic is very appreciated. My main question is will replacing this op amp fix this amp if there is no other burn out components or damaged solder leads? I know without testing everything on the board it is basicly a crap shoot but is it possible that this chip fried all on its own without anything else damaged before or after it on the board?
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Old 22nd November 2012, 03:01 PM   #6
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Actualy looking at the schematic in the service manual it is the top one.
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Old 22nd November 2012, 03:09 PM   #7
Pemo is offline Pemo  Mexico
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Quote:
Originally Posted by Steelbox View Post
Thank you for the download. Any and all information on this topic is very appreciated. My main question is will replacing this op amp fix this amp if there is no other burn out components or damaged solder leads? I know without testing everything on the board it is basicly a crap shoot but is it possible that this chip fried all on its own without anything else damaged before or after it on the board?
LM3886 shuts itself off when it reaches dangerous temperature.
There should be another problem.
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Old 22nd November 2012, 03:13 PM   #8
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I realy dont have too much experience reading schematics but from what i can see it is power amp U1
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Old 22nd November 2012, 03:26 PM   #9
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I would first unsolder the bad chip
Then I would check/replace the main fuse and serial connect a 60w bulb in series with the mains.
Thus you will see if the rest of the amp works.( bass section)
The bulb will prevent from burning more components.
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Old 22nd November 2012, 05:35 PM   #10
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That sounds good thank you but where do i connect the bulb to? The op amp directly ? I am an electrician by trade but i am new to electronics. I rebuilt a few things the last being i changed the chips and a few capacitors on a technics 1200 turntable and got it working but i generaly dont know too much about circuit boards. I catch on pretty quick though so if u could please jus breifly describe wat to put where i can usualy figure it out. Thank you all so much for taking the time to help me.
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