Hello, i have a problem with my sub.so yes, I gave my amplifier to the service because it wouldn't turn on, unfortunately the servicemen weren't able to fully repair the amplifier, that is, the amplifier turns on after the service but two diodes start to light up: power and protection, then protect goes out and the limit starts to light up. The service stated that there was a problem with the control of the transistors, which overheat and then burn out and that they had a problem with the device documentation (whatever they meant) and that was the end of the service adventure. The amplifier is already with me and I decided to see what was actually happening. And it looks like the transistors are actually heating up and very quickly because the thermal imaging shows 70°C and that in 3 seconds. And that's without connecting music, just turning it on. I don't turn it on for longer than 10 seconds because I'm afraid that further damage may occur. I took a photo which. These are transistors Q414-314- Q413-313 and Q103-Q107. I also noticed that they decided to change the carbon resistors R344 and R345 to regular high-power resistors. Has anyone had such a problem with such an amplifier, or knows what steps to take to find the cause?
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And weird thing. Out of curiosity I decided to check if the amplifier works at all and I connected it to the speaker and to my surprise it does work. However, these transistors are still worrying, because so far the highest temperature I have recorded is 70 °C, after which I immediately turned off the amplifier, I do not want to find out if the transistors can heat up even more