The beep is the 3 chanel of my 3pk, I´m change to second gear.

sounds 100% the same than a thermal shutdown.

The 3pk has the ability to change the tone (100 tones in all) of its beeps and probably that is why you thought that its similar to a schulze shuttdown beep.

Captain harlock
How I can to change the tone in my 3pk?

Go to the third menu and then choose the term SYSTEM. There you have six modes where you can toy around with. Choose the 4th mode which says: BUZ-TONE: choose from between 100 different types of tones. The higher the number is, the sharpest the tone is and vise versa.

Ok
Thank you much