Hi,

Looking at the lower picture, there are connections for (from R to L) speaker L +ve, L-ve, R +ve, R -ve then I think it is Batt -ve and Batt +ve.

I suspect that the two wires (red and red/green) on the Batt +ve and Batt -ve go to the other headphone cup where I think that the AA battery may be located. The specs say that it needs a AA battery to drive the bass.

You may have to open the other speaker cup and replace the battery.

Hi,

As you have replaced the battery and verified that it is in the correct way, check the following:

With a DMM (Digital MultiMeter - Voltmeter function) check that you have 1.5V DC across the Batt +ve and Batt -ve connections on the circuit board. If not ensure that the battery holder terminals in the other speaker cup have enough tension on the battery for a good connection and that they are bright and shiny. Here is a link that shows how to increase the terminal tension.

https://www.youtube.com/watch?v=sw495C-A....

If there is still no battery reading across the battery connections on the circuit board then you have to remove the battery and using the DMM (Digital MultiMeter - Ohmmeter function) check for continuity of each of the wires from the battery holder terminals to the circuit board. If one of the wires is open then you will have to remove the battery holder and inspect the connections underneath.

If all the above checks prove OK and you can read 1.5V DC at the circuit board then there is a problem on the board. Unfortunately, without a circuit diagram it will be difficult to ascertain which component is faulty .