RZ12A V3 portable speaker not charging correctly and sounding distorted

Thread Starter

jbharaj

Joined Apr 14, 2022
4
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.
 

Attachments

KeithWalker

Joined Jul 10, 2017
3,063
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.
 

Thread Starter

jbharaj

Joined Apr 14, 2022
4
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.
 

KeithWalker

Joined Jul 10, 2017
3,063
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.
 

Thread Starter

jbharaj

Joined Apr 14, 2022
4
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.
 

KeithWalker

Joined Jul 10, 2017
3,063
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..
 

Thread Starter

jbharaj

Joined Apr 14, 2022
4
I figured this issue out. Sorry for the late reply. I forgot to mention that I moved this speaker from England to Canada. The transformer inside the speaker is rated for 220-240V and Canada is 115V. I ended up changing the transformer out to allow 115V input and 12V output for the circuitry and everything is working as it should.

This would also explain why it wasn't running correctly even when connected to constant mains power.

Thanks all.
 

daba1955

Joined Apr 27, 2019
181
I figured this issue out. Sorry for the late reply. I forgot to mention that I moved this speaker from England to Canada. The transformer inside the speaker is rated for 220-240V and Canada is 115V. I ended up changing the transformer out to allow 115V input and 12V output for the circuitry and everything is working as it should.

This would also explain why it wasn't running correctly even when connected to constant mains power.

Thanks all.
The transformer in my RZ12A V3 is rated at 110/230V, and it has an unconnected (but thankfully sheathed centre-tapping. That'll be the 110V connection. I suspect that if you had just swapped that with the red wire on the power input socket it would have worked in your country. Of course I hope you have labelled the power-in socket accordingly, it says it is 230V,2024-01-01 13.04.45.jpg2024-01-01 13.04.59.jpg2024-01-01 13.05.05.jpg

But dang !! I was hoping someone was going to chip in with a circuit diagram for this board, because I have a slightly different issue.

There is no Auxiliary 12V output on the spring-loaded terminals. The support people have told me that this is a 12V INPUT !! which I find incredibly hard to believe .... No-one in their right mind would use spring-loaded terminals for a power input ....

Anyway, I guess I'm going to have to trace out the circuit board and come up with a schematic to see where the problem lies....
 
Top