Repair KIPUS MZ-70 (very similar SPL DYNAMICS D7S)

[yoppi]

Hello

I repaired power supply a of amplifier KIPUS MZ-70, (amplifier very similar to SPL DYNAMICS D7s), suffered a reverse polarity and exploited all transistors (IRFP064N) and gate transistors and IC TL494.
Is completely repaired the amplifier and transmit audio without distortion, but I have noticed that the output transistors (IRPF360LC), slightly increases its temperature without charge ... The transistor gate has a square wave and the voltage rail is + 122v and -126v ...
Why this increase in temperature of the IRFP360LC?

Greetings.

 

[Perry Babin]

The temperature has increased compared to what?

 

[yoppi]

Hello
From the experience I have, the output transistors do not have to be hotter than temperature there is in the room, without connected speakers.

Greetings.

 

[Perry Babin]

It depends on the amplifier and the time left on. If all of the outputs are heating at about the same rate, I'd expect it to be normal.

 

[yoppi]

Hello

Yes, all are heated equally and at the same time. I will try to load (in the car with subwoofer) and I say happen.
Perri, what procedure you use to make sure the transistors mosfet output a digital amplifier are working properly and will not have problems in the future?

Greetings and thanks.

 

[Perry Babin]

I don't have a foolproof method for every amp. I look at the drive waveforms before (and when possible) after installing the outputs. If they look OK and heat evenly I drive the amp as hard as I can on the bench for about 2-3 hours. If it survives that, It's generally reliable.

 

[yoppi]

Perri, thank you very much.

Greetings