Help with bluetooth speaker

[madan1]

Hi everyone.
Can anyone help with a non-working BT speaker?
Unfortunately there is no service manual and I really doubt there is any. I tried searching for datasheet for the BT module, but again no success. edit -
So here are the symptoms:
it turns on and connects to a device, but as soon as any music is played it reboots.. I mean, a song starts and milliseconds after that it shuts down and boots up again. Without anything played it stays connected.

What I've tried:
replaced the thru-hole cap - no change
bridged the AUX so that it always use the BT input
reheat the smd stuff - no change
replaced the BT crystal and the BT cpu(?) from another module - did not work ( unfortunately the other BT module has different layout and it cannot be used on this board )
removed the class D amp IC - no change
run the thing without the speakers - no change
bridged the upper end of R37 to the solder blob on the other side of the board ( suspected bad hole connection/bridge - the green circle )

What I've discovered - when heat is applied in the red circle area, the module gets better.. I managed to get about half a minute sound out of it... still not crystal clear ( some noise and crackles ) but definitely sound.

So any ideas?

[mmartell]

Re: Help with bluetooth speaker

R33 looks kinda fucky but it could be that the whole board looks kinda fucky.

Touch up all the joints on those smd caps and resistors. One of those caps could be cracked too but not yet full on shorted.

[tibimakai]

Re: Help with bluetooth speaker

I would clean that board first, it is very dirty.

[redwire]

Re: Help with bluetooth speaker

I'd clean that filthy pcb, put it in a bowl of IPA and soak for an hour.
Then use an old toothbrush and gently scrub off the flux and crud. Rinse and let it dry for a long time.

[budm]

Re: Help with bluetooth speaker

It looks like water damage as you can see the area next to R3, 13.

[madan1]

Re: Help with bluetooth speaker

The board was clean when I first got it.
All the dirt is flux residue and heat decoloration/damage.
Indeed I was about to throw the whole thing away ( even removed the USB port to use it in another project ), when I noticed that when certain area is heated it gets better.

[Agent24]

Re: Help with bluetooth speaker

Clean everything, could just be leakage affecting the circuit.

[madan1]

Re: Help with bluetooth speaker

Unfortunately after a couple of desolders of the bluetooth unit, I finally managed to fry/wipe out the memory chip and now I just get some error beeps when apply power.
Before that I was able to get few minutes of music by heating up random parts of the board...

At least I spent some time getting familiar with that modules and now I think that it will not be that hard to find an even better substitute module.

[tomodachi]

Re: Help with bluetooth speaker

see alibaba for plug and play diy bluetooth modules if u think your device is worthy