Broken Yamaha R-500

[Helen]

I have a Yamaha R-500 receiver that has stopped working. When it stopped I heard the speakers pop. When I tried it several other times the speakers popped again. It does not work with the head phones and I also hear the popping sound with the head phones. The speakers do work with another receiver. The power is on and the radio appears as if it is working but with no sound.

After researching on the web it appears that the STK 3042 II could be the problem. I’m guessing that the Power amp STK 2040 is ok because it has power. Would this be a correct assumption? Hopefully that is the case because I can’t find a 2040 but can find a 3042 III. I’m guessing from what I have read that the 3042 III is a good substitute for the II. If it is the 3042, how do I get the old 3042 II out?

Thank you very much for help with this project.