I am trying to figure out why this portable speaker is sounding distorted even when plugged into the wall. My initial feeling is that its related to the 12v charging circuit but I may be wrong. The speaker was sitting from 2017 in a box and I opened it a few months ago. I tested it and straight from the get go, it sounded distorted. I left it to charge for a few days and tested it again whilst plugged in but still the same. The distortion is more so at volumes past halfway as I am guessing the voltage/current requirements are higher.

I opened the speaker and tested the sealed lead acid battery with a multimer and it was dead and it didn't respond to being charged with a 12v charger. Ordered a new battery from Amazon and it worked well for a day or 2 and same thing, started distorting. I guess it used the charge from the battery and once drained, started distorting at higher volumes. Also, the charge light is continuously on even without being connected to the battery.

So i am not sure what the underlying issue is so i am hoping someone could help. Hopefully i have given as much information as possible.

 

I assume that there is a built-in charger for the 12V battery. It would appear that the charger is not working. Check the fuse first and then the rest of the charger circuit if the fuse is OK.

 

I assume that there is a built-in charger for the 12V battery. It would appear that the charger is not working. Check the fuse first and then the rest of the charger circuit if the fuse is OK.

I checked the voltage with a multimeter from the wires that are connected to the battery and it shows just over 9 volts being outputted from the board. I have attached a picture showing this. The main fuse is ok. I wouldn't know what to look at on a component level on that board to find the fault.

 

9V is probably just the battery voltage. Disconnect the battery and with the power turned on, measure the voltage between the two wires you disconnected. The open circuit voltage should be around 16V. If it is not, you will need a circuit diagram of the charger board to do any more trouble shooting.

 

9V is probably just the battery voltage. Disconnect the battery and with the power turned on, measure the voltage between the two wires you disconnected. The open circuit voltage should be around 16V. If it is not, you will need a circuit diagram of the charger board to do any more trouble shooting.

One of the pictures I have attached shows the voltage between these 2 wires as 9.34V. I did try and scour the Internet for a schematic of that board but to no luck. Even if I could find a replacement but it doesn't seem to be available anywhere.

 

One of the pictures I have attached shows the voltage between these 2 wires as 9.34V. I did try and scour the Internet for a schematic of that board but to no luck. Even if I could find a replacement but it doesn't seem to be available anywhere.

In that case. it would probably be best to replace the existing charger module. There are lots available on the internet for 12V sealed lead acid batteries..