Why ? I had some music and sound, but it was very dirty, and noisy. In 95% of the cases, it's due to dry capacitors or failing capacitors.
Since the CPS-2 board (at least all those i bought lately) had almost no sound, the culprit stands on the capacitors most of the time.
I have removed the big one, and tested it with my ESR meter. LOL almost 1200uf when it should be 1000uf......
I have also replaced the capacitor 220uf 16v which sits next to the push button sound levels, because the sound high and low was not reacting.
Once removed, tested with the ESR meter. Same as the big big one, the value in uf was 289uf instead of 220uf. Crap value.
For security, i replaced as well the 2 220uf 16V just aside the Sound AMP chip.
PS : Capcom CPS2 are pure bitches for servicing, it requires 350°C to correctly remove the capacitors, and a hole cleaner to make it nice and clean.
For pictures, i will post them tomorrow