The real problem is sometimes further in the circuit. Like ‘forest’ was saying in another topic I fixed a couple of them by replacing only the z4 zener diode. It gets really hot during operation, and stuff just breaks: Had the same issue, caused by the heat around Z4 diode. Fixed by replacing the dead cap C74 (100u/16v) and the diode Z4 (12v 1W zener 1N4742), check maybe you need to replace more components, R2 for example. This area of the pcb is generating “mute” signal for the amp, so no wonder the trick of cutting “mute” pin of tda7265 works sometimes If you want the simple solution. you don't have to cut the pin (messy), just cut the jumper in the red box: