Europower pmp5000 no amp sound when cold start

[stelioskoz]

Hi i have behringer pmp 5000 and i have this problem.
when i power on for first time ,the mixer starts normally but the amplifier not working. After 5 - 10 minutes the amplifier start working. Then if i power off and on again ,then amplifier starts after 3-10 seconds and working fine. The voltage on the amplifier is the same all time. So i think that the problem is on my amplifier. Can you suggest any solution? Thank you!!!! Sorry for my bad English.

[stelioskoz]

So finally i manage to fix the problem. That was capacitor c66 2,2 μf 50V on the amplifier. Now the mixer and the amplifier starts normally

[Jazz P Bass]

Congrats for finding that.

[stelioskoz]

Congrats for finding that.

Thank you jazz p bass!!!! I measured the voltage on c66 it was 4v and every second it goes up and up and after minutes the voltage was 8 v. Then the amplifier started. So i changed the capacitor and the problem fixed.

[Jazz P Bass]

So that resulted in the output of IC 6 comparator staying low.

[stelioskoz]

Jazz P Bass Yes i think this circuit is for safety. If the amplifier is very hot then the thermistor R1 change the resistance and the ic 6 cut the amplifier

[Helmholtz]

R1 seems to be a thermistor but certainly not a varicap (= variable capacitor).

[stelioskoz]

R1 seems to be a thermistor but certainly not a varicap (= variable capacitor).

Yes. sorry it was my mistake!!