Just shooting from the hip here but I'd guess that the power supply is overheating.
- Maybe... Do you know what would be a decent operation temperature? I will try to find a way to measure it
Do you have it in a dusty environment?
No. Only in my apartment, never get it out.
Do you own a cat or a dog?
None. The only animal who lives here and touches this keyboard is me myself.
I'd suggest opening it up and vacuuming the crud and dust out of the chassis and power supply and see if that fixes it.
I already did that and got no success. But I will consider your tip on the temperature.
Thanks man, really appreciate your support.
Best regards.