Weak subwoofer sound output

Hi,
I recently got an apparently faulty logitech s220 2.1 speaker system. The speakers sound fine but the sound of the bass is very low almost inaudible. The system has two volume control. One is the main and one for the bass only. Both seem to be working properly as on max volume there is sound coming out from the bass but if I turn either of them down the sound dissipates. The speaker itself works. I tested it on another system and also with a multimeter.

On the back of the PCB where the IC is soldered I saw light brown burning signs so I thought the IC is out and replaced it with similar one (CD6282CS) as I couldn't get the exact same model (D6282). The problem is the after replacing the IC the exact same problem still there. The bass is still low. I've attached two images about the pcb after replacing one of the ICs. Please excuse my poor soldering :|

So my question would be how should I proceed from now? Is there a way to figure out quickly and easily what could be wrong? I would be happy even with high probability guessing too if that saves me from pulling out all the bits and bobs and testing them one by one.

Your first paragraph seems to say that the sound system is working as it should, so why did you bother to change any components? I have the same sort of speaker system but from creative. One dial turns up volume, the other turns up bass, that is how they work, that is not a malfunction!

The problem is that no matter how I turn the volumes up the bass is just a tiny little whimper. The two speakers are fine but the subwoofer volume stays low.

Ah, that's more clear now. The potentiometer on the bass knob could be worn out then, you'll have to go full Big Clive on it and pop the enclosure open. It might be fixable...

As you can see the attached pictures it is already popped open. So you say the potentiometer is worn out and that is why the subwoofer sound is low? But I can control the volume with both of them only it's lower than it should be.

Hi,

Some products are 'good', some are 'not so good', either as a whole or for one aspect or another. I have a very old mobile (circa early days of partial touchscreen mobiles) and a not so old mobile by the same manufacturer. Old one has a great and loud speaker system and good Megapixel camera, newer one is barely audible and the camera is like the original Mario Bros level quality... Progress, backwards is forwards...

Have you looked for a service manual schematic of your circuit/speaker system. There are plenty of websites with those things. It might turn out to be a time-consuming waste of time or bring up a schematic of the speaker circuit.

If you are good at troubleshooting, I'm not much good at following unknown circuits with a DMM and 'scope to understand faults, you could measure voltages around the circuit and see if they 'make sense' - with a schematic and some maths, you may be good at working out what should be happening around the circuit. It may also give you an idea if you can get away with changing the bass pot. for a lower value (or maybe even higher value, who knows) one to see if that helps.