Take the back off of the unit and remove the wires from the LED Woofer and Tweeter.
Power the unit back on and test for DC on the woofer and tweeter connectors, found less than 1 volt.
Did not think that both of the LM3886TF IC were bad. Looking at the input pin 10, I find no music. output pin 3 had a strange wave form that was not affected by level.
Checking the bridge, found 24v and -16v, the 6800uf 25v caps ends were pushing out, they would have to be replaced anyway. After replaceing them the voltage return to -24 and +24. They are running the power supply at max with 25 volt caps. Did not have any 35 volts that would fit.
When removing the caps, cut the glue from arround the caps first. This PCB is double sided with eyelets that connect between each side. If you rip out the eyelets when removing the caps you will have to solder a jumper wire to complete the path.
Unit now is working again.
Hi, great post,
ReplyDeleteI have previously replaced the caps in a BX5a with a buzz and thump on turn off. same issue.
I also am trying to fix a BX5 (not the a model). Easier to get apart.
I wonder if you can advise. This speaker doesn't have a buzz, just a loud rustling sound, like stroking a mic. It appears to be independent of the volume setting or EQ ?
Internally the caps all look fine and no components seem to have burned out.
Just measure voltage across filter caps and if you can look signal with the scope
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