Siren-like noise from PA4X

[PAPAPETE]

Hello all,
I have been performing with this monster keyboard since purchasing in 2017. I've never had any issues...until recently.

A few weeks ago, in the middle of a song, all of a sudden there is this extremely loud siren - like sound. At first I thought it was a local distress siren, but no. It was being generated by my trusty PA4X. I shut the keyboard down, waited a minute, then rebooted. Everything then functioned properly until yesterday, when the same thing occurred, but luckily in my home and not at a gig this time. I once again shut down the keyboard, waited a few minutes, then rebooted, and keyboard once again is working perfectly.
The first time it happened I was playing through powered speakers. The second time I was using headphones only in my little home studio.
Has anyone else encountered this problem, and if so, do you know what caused it, and finally, were you able to trouble shoot and fix it.

Many thanks in advance, and Happy New Year to all!!

[BR]

Yes, It happened exactly the same thing with my Pa4X during a gig few years ago.
I rebooted and it worked ok.

I have a post about this issue:
http://www.korgforums.com/forum/phpBB2/ ... ight=noise