If you changed the capacitors and they're still static, sometimes it could be underneath the chip where either:
A) leaked electrolyte caused damage to the traces underneath, or
B) the original capacitors were on for a long time, leaked, and over time caused their ability to filter voltage to fade and therefore causing damage to the op-amp or DAC underneath the chip.
You're next step, in my opinion, should be to remove the hybrid sound chip from the PCB, clean it well, reflow solder **carefully** to all 64 pins, then use chip quik to remove the op-amp (LM358 replacement part), and check continuity of the traces between the op-amp and corresponding pins; repair traces by jumping with 30 awg kynar wire if needed.
Last but not least, if there's still static after all that, you may need to replace the DAC (AD1868 replacement part only available through AliBaba/AliExpress).
I'm going away to Greece tomorrow and won't return until July 30th, so when I get back and if you're interested and don't want to attempt to repair the sound chip, you could send me the board for repair.
If you're comfortable removing the sound chip though, definitely pick up some extra chip quik (leaded only, don't bother with the lead-free as it's much tougher for this job). And make sure you have a desoldering gun like a Hakko 808 or so - both tools will help make the removal easy.