Greetings, I have a digimod 1000 amplification module that is from an rcf art525a box. It happens that it turns on well, audio is sent to it and the signal LED turns on all normal but there is no sound. [list=1] [*] When the amplifier is turned on, a noise like "snoring" is heard on the speaker, that noise is for 1 second or so only at the moment of switching on and then disappears. [/list] At the time of reviewing it, I found a resistance that had broken in half (R79, 7w 4,7ohm) I suppose that due to overheating, I changed it, check that nothing else was defective and I turned on again but the same fault continues. Also change mosfet Q5, Q6 (IRFP260NPBF) and the fault persists. Someone has worked with this board, any suggestions, thanks in advance.

Thanks for the help, I commented that I was able to get another board of the same model and what I did was to exchange its modules (attached photo) and it turns out that when making that change the amplifier worked perfect, then by conclusion, the said module is the one that brings the problem. Now as you can see in the photo, all its components are SMD and the revision is complicated, at first sight there is nothing defective or burned. Any ideas to find where the problem is ..? NOTE: The diagram is on page 15 of the file sent to me by Alto-APM-200