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Trying to Fix Bluetooth Speaker, please help

Discussion in 'Troubleshooting and Repair' started by davewheeler, Oct 19, 2019.

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  1. davewheeler


    Oct 19, 2019
    Just got this speaker and it worked ok but then stopped working after barely any use.

    leds still flash and I can connect to bluetooth but no sound.

    I opened it up and had a fiddle with it, got it to work again by sticking an allen key between the battery terminals on the board creating a spark, came straight on. but if you turn it off and on again by the switch it doesn't work again. The allen key thing works pretty reliably but I admit it's not ideal.

    Also it buzzes when connected to the power but not when its just playing from battery.

    Can anyone diagnose the problem from this?
  2. davenn

    davenn Moderator

    Sep 5, 2009
    Some sharp and well lit photos would be great .... and including how you were shorting out the battery holder

    So, this thing is mains power AND battery powered ?
  3. 73's de Edd

    73's de Edd

    Aug 21, 2015
    If this involves a plug in power connector and additionally there is a leaf switch that is electro mechanically built within that connector.
    Be sure that switch makes its proper connection when a plug is connected in .
    That might relate to why the pressure of an allen wrench mechanically shifts or distorts , to get that operational situation.

    OR . . . . . check the solder connections that are made from the connector into the circuit board.
    One of its terminal might be time related and repeated plug ins. . . . now floating loose within its solder joint, thus the possibility of a spark being seen as it makes or breaks contact as its position is distorted and displaced laterally by a plug in action. Your pressure tthen distorted it into temporarily contacting.
  4. davewheeler


    Oct 19, 2019
    best I can do right now.

    it’s battery powered yes but also has a plug, to recharge, I’m assuming it should work while plugged into mains

    made it go by touching the two points below the red connecter in the first pic 6FD0BD66-8D2F-4512-9160-89F87BF1A121.jpeg C43E1E53-1324-4682-96B6-DF039132E545.jpeg A3DC4AB6-1715-48D9-940D-CC2ED24957CD.jpeg
  5. davewheeler


    Oct 19, 2019
    thanks, there wasn’t any pressure or mechanical distortion, just used a piece of metal to connect the two points.

    can’t see any cracked solder but obv I’m no expert. I jiggled just about everything I could and would have thought there would be a buzz or a crackle during brief moment of connection if that were the case, but so far it’s just silent or on and working fine after that spark.
  6. Ylli


    Jun 19, 2018
    How about you tell us the make and model?
  7. Bluejets


    Oct 5, 2014
    Not a good idea to go around shorting things out in any piece of electronic gear, could end up smoking the whole box and dice.

    Following the red and black lead from your red plug for example, appear to go directly into that black plastic enclosure ( battery box??)
  8. davewheeler


    Oct 19, 2019

    Intempo 1447
    Last edited by a moderator: Oct 23, 2019
  9. davewheeler


    Oct 19, 2019
    probably not, yes its the battery box
  10. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir davewheeler . . . . .

    One finds absolutely somewhat less than 0% service info / schematics being available on that "Unicorn" unit .

    By astute techno observation, one sees that the External DC power comes into the far left 2 pin connector.
    The next 2 pin connector is receiving the battery box input.
    The final 2 pin connector just routes over to the main power switch.

    Lastly are the two irrelevant speaker plugs.

    Soooooooooooo . . .if you electrically jumpered across the RED BOXED power switch connector. WITH THE MAIN POWER SWITCH IN ITS OFF POSITION, you just effectively jumpered across the switch and turned the system on, for the duration of that connection being made..

    For the second aspect on the noisy audio / or / hummmmmmmmmmming noise . . . . did you use the factory specified or supplied wall wart ?
    If not, I would suspect that batteries are being needed in the unit also . . . . with them then sort of acting as a supplemental and additional " filtering" of your external DC

    You say . . .
    I opened it up and had a fiddle with it, got it to work again by sticking an allen key between the battery terminals on the board creating a spark, came straight on. but if you turn it off and on again by the switch it doesn't work again.
    I say . . .

    You describe the efffects of that main power switch being bad. Leave it in itts off position. Place a jumper wire across it right at its terminals , then confirm that the unit will work with that connection being made 10 out of 10 trys . . . .if so . . . .then replace that dern switch.

    Now if you shorted across just below the RED plug which goes direct to the battery box and it has fresh batteries inside, it should spark, but NO logic in the unit coming on and working afterward.
    My different photo shows the same wire routing directions and the connectors are probably mechanically keyed so that a connector cannot be plugged in, other than being in its correct position.



    73's de Edd . . . . .

    Next time you go out to eat in a fine restaurant, and when the maître d' asks where you would like to sit, ask him for a table near a waiter.

    Last edited: Oct 20, 2019
  11. davewheeler


    Oct 19, 2019
    Many thanks, my liege, for your eloquent response and commendable effort.

    Sadly your switch theory holds no water; it was 100% the battery box connection I was shorting, and not the switch.

    Illogical, maybe, but as true as the concerto emanating from said unicorn's maw as I write these very words.

    Update: I have also had similar success with a perfectly timed jamming in and out of the charger in the back of the device.

    Someone has suggested that a momentary dip in power created by either could be compensating for a faulty capacitor.
  12. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir David Wheeler Esq . . . . .


    So the main switch is definitely OK and you definitely were shorting the battery connector box out. If that is using Dee size cells . . .vice Cee's . . . and a sum of 6 of them, a dead shorting across them, would have each of them pumping out fom 5-6 amps / 30 w for short durations. BUT the consideration was that you were shutting off power to the main system, alhough, be it in a quite spectacular way.

    I see a ver r r r y l o o o o o w probability of ANY service info being forthcoming or being found for that unit at this time..

    Now, with you having the main power switch at its on position at all times.
    Confirm for me, does 1 jump across, accomplish that desired effect or might it take multiple times to finally end up with the unit coming on, working normal and renaining on until you finally turn it off with the main power switch ?

    So lets blaze ahead and see what facts we can develop from a close in photo examination of the boards topside and the bottom foil trace interconnects.
    We see that the closest terminal to the corner will be the DC adapter power plug then the battery connector plug and the final power switch plug, with the two internal speaker plugs being of no interest to the problem.
    Looking at the foil side of the board we see all negative leads soldered to the ground plane foil, the positive leads float, but they are being within TINY foil islands.
    I see the corner plug + connection traveling down the edge of the board until I can see it no longer.
    I can not see either of the two other plugs trace paths since they are on the other unviewable foil side of the board.

    The most power used in that unit would seen to be with that AUDIO amp IC that you see right beside the speaker plug connectors. Read its part number on its top and pass to us so that we can see if 9 volts is being at its lower parameters, that the unit will work at.
    Otherwise, I could see that, being hidden back in the left quadrant of the circuit board, that they are using a switch mode boost converter to hop up the supply voltage .
    Your disrupting the power with a short . . . . and its resultant loss of power . . . . could KICK the inoperative converter into operation, as the power comes back.
    That being considered, and not shorting the battery connector, instead , how about a more direct approach by using just battery power and then you just turn on the power switch and unplug and plug in the battery connector to blip-blip-blip-blip-blip-blip the power on and off several times to see if the unit jumps into operation just after one of those power plug in / turn on blips.
    That replicates your shorting action in turning the unit on and off but the batteries will be happier.
    Also you might just try flipping the main power switch on and off in the same manner.

    You say . . .
    Update: I have also had similar success with a perfectly timed jamming in and out of the charger in the back of the device.

    Which means that this below is then confirmed . . . .
    Stepping ahead, with not yet knowing your prior results, then leave the power switch in its on position and move down to the AC wall warts end connector and accomplish the same fast on off effect with the unplugging of THAT connector into its receptacle to see if that makes it work . . . . if your timing is right . . . . and you are holding your tongue, now pressed into the side of your jaw . . . just in the right position.
    Leave it plugged in if the unit comes to life at some attempt.

    Until I see a good photo that will let me see the foil path interconnects between the power switch, the battery holder, the wall warts connector plug AND their actual power connection being eventually made into the circuit board; I am currently seeing the wall wart connector plug directly having its connections co-joining with the battery connector.
    Then the power switch connects their shared + connection into the + buss of the circuit board.

    E- capacitors . . . . I see 4 of them across the board near the connectors 1 at the center of the board near an 8 pin IC . . .its numbering I.D. is being needed . . . . and it is of a skimpy/minimal 10VDC rating . . . used with a 9V power supply ? ? ? ?
    The next two units sit either side of the AF power IC, I need the IC numbering and the voltage rating of those caps in case that chip is operating at > that the 9DC of the battery supply (via an on board power up converter circuit ).
    Then we see the final E-cap in that row and it looks like a 10V rating on it also.
    Then nearby, sits a dumbell shaped ferrite cored inductor with its magnet wire winding. That could be used in series with the incoming power for EMI / RFI /HASH AND CRAP filtering . Or it COULD be associated an earlier mentioned DC up converter supply, as being its ringing inductor, but NOT into that NEARBY cap with its mere 10VDC rating .

    Seems like at least two E-caps are hidden from my viewing, at the other end of the board, can you supply their values and VOLTAGE ratings . . .plus positions .
    Another photo of that area might answer all, as to there being an up- converter power supply hidden in there.
    A deteriorated, marginally low value E-cap in those positions could account for exactly your needing of " kick starting " the unit .

    Thaaaaaaasssssssssit . . . .fer now . . . ..

    73's de Edd . . . . .

    The things that come to those that wait, just may be the few things left by those who got there FIRST.

    Last edited: Oct 23, 2019
  13. davewheeler


    Oct 19, 2019
    so to recap,

    shorting the battery with a jumper wire still works but yes it takes a few tries.

    disconnecting the battery entirely and plugging the charger in and out also works, again, unreliably.

    there are 5 of those CAPs, I think they are all the same 10V then one larger one at the back left which is 16V. I will supply some better pics which I think have the info you were looking for, including the battery, 7.4V

    wasn't able to upload the pics directly, too large maybe, but please look here
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