Sudden lack of audio on 2001 Prius

About 2 mos. ago, the CD player on my 2001 Prius stopped delivering sound. The player appeared to be working, but nothing came out of the speakers.

So, I ignored the problem. Now, nothing–not the FM, or AM, or Cassette or CD player deliver sound, although all otherwise appear to be operating - I can see what station I am not hearing or what CD track is not coming out of the speaker.

Ideas? Good place in the Boston, MA area that might be able to diagnose?

Could be a blown amp, or as simple as a blown fuse. Assuming you can’t handle the fuse issue, your local car stereo shop can help you out. No specific recs for you though.

I checked the fuses, and at least as near as I can determine, nothing else connected to either of the two fuses that the owners manual says are related to “audio” has been affected.

I got some confirmation that the fuse might not be the problem when the sound suddenly came back on, for just a few minutes, a few days after this happened. Then, while I idled quietly at a light, all went abruptly silent, again.

How hard is it to diagnose/replace a misfunctioning amp? Is this a $100 repair? A $1000 repair?