It works but no sound

I found my chilhood N64 and it did’t work, so I cleaned it and it worked but no sound. I have checked the cables and conectors with a multimeter and they are fine. In my research to find a solution I have found that the capacitors that process the audio might need replacing and that HDMI ultra mod bypasses this problem and does the processing on its own. The HDMI mod its way too expensive for me, so my question is: wich capacitors I have to replace on the board and how do I do it without messing up my N64?