I haven't opened up either to look inside yet.
One has the classic no sound problem, from both the speaker and the headphones. I suspect it would be a simple case of replacing the capacitors.
The other, will not power on at all. My question is about this one. What are the likely causes of a complete failure to even power on? Does this automatically mean this system is only good for parts now, or is there a fix for it? I'm assuming you could replace the power supply if that was the problem? Is that worth the effort? Any ideas?