Loudspeaker sound no longer works after 10 seconds

Hello dear community, I have the following problem: I have been retrofitting a new radio and speakers in my Mercedes Benz W202 C180 Bj 95 for six months now. Since the day before yesterday the speakers no longer go, at first the sound was only short and then came back again, but now the sound is completely gone. When I disconnect the battery and clamp it again, I hear again 10 seconds well over the loudspeakers, whereupon a dull noise sounds and the loudspeakers go out abruptly. I ch have connected my old radio (from the factory), here everything runs without problems (sound without trailer). I tracked down my amplifier, which is connected to the terminal 30,15 and 31 to the ISO plugs. Can it be because of this? Although it worked with the new radio for half a year without problems and with the old still everything works? Or maybe it is on the adapter? Have made some pictures of the amplifier and of my ISO plug and adapter:https://pl.vc/q3ghn https://pl.vc/15u6eihttps://pl.vc/14zm0vhttps://pl.vc/14pl4whttps://pl.vc/9xnrmhttps://pl.vc/13k4ds I would be very grateful for a quick answer. Mfg Timon98