Speaker Volume Low

[High Roller]

I have a Curtis RCD8563 CD Stereo stereo with four speakers. Recently, I've noticed a reduction in speaker volume in one of the four speakers. One jack has no effect on the speaker when I take it in or out. The volume in the right speakers is about 50-60% of that of the left. This is true with when using the headphone jack as well.

I've traced the wires from the jacks to into the first circuit board and each of the four wires (in a band) seem to have conductivity. I then traced six band wires from one circuit board to a second board and those have conductivity also. I haven't tried voltage tests as I don't know where I should be reading it.

Any ideas of how to approach this? Oh, the sound from the Radio is also the same low volume out of the right speakers. It's not the speakers---I tried reversing them and same problem. One of the jacks is dead (???) but the wires from it show their good.

I'm a novist at this so any input would be appreciated.