The previous term I used to describe the sound I get, fits pretty well: sawchain

Imagine a very loud 90s modem, the sound when connecting to internet in those times, something  like pink noise modulated by a S&H, that gets re-triggered each time I push a key. No, no synth sounds at all. :(

I tried removing and reinstalling the D/A chips, unfortunately nothing changed.

If useful, I can upload a video to let you hear the noise.

Thanks so much!