Stereo started smoking!!!!!!!

Discussion in 'The Projects Forum' started by EarlAnderson, Jul 18, 2012.

  1. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    Just a while ago my stereo started smoking. I took it apart to see what was wrong and i found 2 SV31 biasing diodes that werent heatsinked good. I thought forsure that this might be the problem but when i tested them with my multimeter, they tested okay. Should i go ahead and replace them anyway
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Not yet, I wouldn't.

    Can you tell where the heat or smoke came from? Post a picture if you can see anything you have questions about. Skilled eyes here might see something.

    What was the stereo (you mean the receiver, right?) doing when it went up in smoke? Did it stop making noise, make funny noises?
     
  3. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    Before i noticed the smoke, i noticed that the right channel started humming and the left channel sounded perfectly fine
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    What was it smoking?

    The right channel forgot the lyrics.
     
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  5. wayneh

    Expert

    Sep 9, 2010
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    That's bad, sort of. It means it's not your power supply and is more likely your right channel pre-amp or output stage. You should check to see if your speaker wires (or speaker) might be shorted on that side. There's a chance the amp protected itself from damage, even though it got hot enough to make a bit of smoke, and might recover once the short is removed.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    :p Smoking the right thing will do that!
     
  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    I guess chips is smoking and is ................High !
     
  8. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    Nope. The speaker wires arent shorted, however i dod notice a couple of lifted copper pads on the circuit board
     
  9. wayneh

    Expert

    Sep 9, 2010
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    Time for pictures. Do you have a schematic? Try googling for it.
     
  10. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    I couldnt find a schematic, and my iphone wont let me upload any pictures.
     
  11. BMorse

    Senior Member

    Sep 26, 2009
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    Sounds like you need a new phone also! :D
     
  12. nomurphy

    AAC Fanatic!

    Aug 8, 2005
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    If you have the box open you can visualy check for burned components, but you can also use your nose to smell for things that overheated or burned (or at least determine an area for further investigation). Just make sure the unit is off when your nose is close to the board(s).
     
  13. wayneh

    Expert

    Sep 9, 2010
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    Awww, you're ruining our fun! :eek:
     
  14. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    I have some news. I found a blown fuse on the power supply board.
     
  15. SgtWookie

    Expert

    Jul 17, 2007
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    Well then, that would seem to indicate that you have a problem in your power supply.

    And it's most likely that you have a shorted electrolytic capacitor.
     
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  16. wayneh

    Expert

    Sep 9, 2010
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    Proceed with caution. It blew for a reason, and it probably wasn't the source of the smoke. But the good news is it may have protected other components.
     
  17. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    I agree with Sgt. Wookie. When I read the post, the first thing that popped into my mind is electrolytic capacitors. When they blow, they let out a LOT of smoke. And when you mentioned that one of the channels started humming, it suggested to me that one of the electrolytics used to smooth the DC after the rectifier in the power supply was blown. Check the capacitors for bulges, holes, and cracks. Chances are that's where your problem lies. Again, a photo of the board would be most helpful here :)

    Regards
     
  18. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    Yeah but im still trying to figure out what the problem is in the first place. I found a couple of lifted solder pads on one of the transistors on the board where i think the smoke came from.
     
  19. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    Ill be posting a bunch of pictures tomorrow. I live out in the country and have slow internet so ill have to post them tomorrow at work
     
  20. EarlAnderson

    Thread Starter Member

    Nov 13, 2011
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    4
    I have good news and bad news. Good news is that i found out what the problem is. Bad neas is is that it's a burnt resistor and i dont know what value it is
     
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