The system burns Psp

I gave it to the service, they started to use it again, it passed, 1 month again, the same sizzle and the same problem motherboard ties burned. I decided to have it done again, but this time I will not start using it without taking my precaution.

The service is called the following: They said this is a problem because the voltage is input from the headphone jack (Audio output).

Now I would be glad if you helped to solve this problem.

Amfi 3000w, I think the amp either draws a lot of watts from psp or gives voltage backwards and burns psp itself.

If we put something in the middle of the audio cable going to this amplifier, it would prevent voltage from coming back or balance it if it didn't draw too much?

PS: Amplifier cable goes directly from Psp. There is nothing on tape. Do I need something fixer on the cable between Amphitheater and Psp?