Creative Labs I-Trigue L3800 Speakers: Signal loss to satellite speakers

Discussion in 'General Electronics Chat' started by Kiwi_Tim, Oct 23, 2015.

  1. Kiwi_Tim

    Thread Starter New Member

    Oct 23, 2015
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    I own some Creative Labs I-Trigue L3800 2.1 speakers.

    http://www.goodgearguide.com.au/review/creative_labs/i-trigue_l3800/219071/


    They are about 8 years old now, and have served me well up until a couple of days ago when the sound to the satellite speakers would stop and start. Sound to the sub woofer does not appear to be affected.

    I thought this might be a faulty 3.5mm cable and replaced it, but that made no difference. I also thought it might be an error with my Samsung TV, but testing the speakers with a PC reproduced the error (although less frequently).

    I removed the circuit board from the sub woofer speaker and all of the components seem to be coated in a plastic coating that might make attempting a repair difficult. I looked at the capacitors to see if any were bloated, but could not see any obvious bad ones. I am quite good at repairing computers, but my knowledge of electronics is almost non existent. I am hoping someone can give me some simple advice at the novice level as to how I should go about attempting a repair. I am guessing that some component(s) on the circuit board have failed or there is a poor connection somewhere on the circuit board. I can not afford to replace these speakers, so repair is my only option.
     
  2. ISB123

    Well-Known Member

    May 21, 2014
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    Pictures and schematics..
     
  3. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Last edited: Oct 23, 2015
  4. #12

    Expert

    Nov 30, 2010
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    6,852
    Start tapping on things and wiggling things...and hope it goes bad. If you don't have a crusty connection, you are in for some intelligent trouble-shooting (which almost never happens in replacing the cards or modules in computers).
     
  5. Kiwi_Tim

    Thread Starter New Member

    Oct 23, 2015
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    I have tried tapping and wiggling connections, but that does not seem to help.
    Here are some pictures. You will see every thing is covered in white plastic. Does this stuff ever become conductive with increasing age? If it does, perhaps removing it might help. I tried chipping some off but it is set like concrete. Any ideas for removing the plastic gunk? 20151024_104017.jpg 20151024_103928.jpg 20151024_104017.jpg 20151024_103928.jpg 20151024_103834.jpg
     
  6. Kiwi_Tim

    Thread Starter New Member

    Oct 23, 2015
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    In the 2nd picture above you can see a square object with black and green plastic bits which is perpendicular to the circuit board. This is where the left and right satellite plug in (on the other side).
     
  7. #12

    Expert

    Nov 30, 2010
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    The white stuff is, unfortunately, glue. It stops vibration from wiggling the solder connections and mechanical connections loose. It never gets electrically leaky (that I know of). It also serves to make repairs so difficult that you feel encouraged to throw this in the bin and buy a new one.

    Is that a JRC4558 on the last photo? It's an old, but well respected audio amplifier. Look to the datasheet to see which pins you find the power supply attached. Pins 8 and 4. Notice the round divot. That is the marker for Pin 1.

    I can't read most of the part numbers, but that is how we start. Find ANY information and work to expand our knowledge.

    It looks like DodgyDave brought a schematic which shows a NE5532. As far as I know, it is an exact, pin-for-pin substitute for the JRC4558.

    This is enough for a start at checking voltages. Be careful about shorting pins together with your volt meter probes. You can smoke a chip in an instant by doing that. If you find the power voltages to be correct and available, the next step is trying to trace an audio signal through the jungle of parts.

    Hint: Most of these turn out to be the power chips, TDA2030.
     
  8. Kiwi_Tim

    Thread Starter New Member

    Oct 23, 2015
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    I think the glue has beaten me. As you say, time to throw it in the bin and get a new one. Thanks to all that have offered advice!
     
  9. Kiwi_Tim

    Thread Starter New Member

    Oct 23, 2015
    5
    3
    I found the problem. The glass fuse was sitting loosely in the fuse holder. I tightened this up and the problem has gone. Hope this may help someone else with the same issue.
     
    #12, Sinus23 and Dodgydave like this.
  10. #12

    Expert

    Nov 30, 2010
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    Did a bit more of the parts wiggling, did you?:rolleyes:
    Glad you found it.:)
     
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