Background: Aftermarket head unit using a MOST converter.
No problems since installed in 02/2020, was also installed for 2 years on my previous 997 turbo.

Music randomly cut off on me while I was driving (the Audio unit was still powered up and showing data). Chalking it up to a glitch with apple Carplay, I switched to FM and there was still no sound.

Got home and shut the car off, then started troubleshooting. I turned the car back on and the audio unit powered up and FM was transmitting sound, but then the sound cut off after about 10 seconds.

I pulled the head unit out and input tested everything on the MOST converter (it's only voltage in and ground) and unplugged the fiber optic connector to verify the red laser beam was on. Since the head unit was out I quickly swapped back to factory PCM and it powered up but no sound.

Took the FRUNK apart and accessed the stereo amplifier and input tested it. Constant 12V and Switch 12V and ground present. Fiber optic laser beam on. At this point it's pretty clear that it HAS to be the amplifier.. I was just curious to see if anyone has had this happen? I google searched and it doesn't seem to be too common.

Weighing my options now... I would hate to spend the money on a new or used factory amp that will eventually fail, but also hate aftermarket stereo systems (even though I have an aftermarket head unit- it's a must for me, factory PCM is a convoluted mess and has no bluetooth/carplay and the maps look like super mario on NES).

RANDOM PIC FOR ATTENTION

 

It is entirely possible this just happened to mine as well. It’s in an audio specialty shop right now. I’ll let you know. My failure sounds identical.

 

My amp on my 997 GT3 was previously repaired by beckerautosound.com. They also added a bluetooth module to my CDR24 so I can listen to bluetooth music wirelessly. Contact them to see if they're able to fix it. I'm getting a strange popping noise from my speakers right after unlocking my car and opening my door and also notice there is always a hiss coming from the speakers, at least for the first 5 minutes until the car goes back into sleep mode and all of the lights turn off. So I'm planning to send my CDR24 and amp to them to have them repair anything that is necessary.

 

I have an aftermarket Alpine head unit (w amplifier and upgraded speakers) and about every twenty times I start the car it shows the message “Check Tuner” and nothing works. Only thing that fixes is it is to turn off the car to presumably reboot it. Not sure it is related to your problem. Can’t figure it out.

 

Had similar issues with the CDR23/Dension in my 03. As they got more common I eventually yanked it to a setup similar to yours. Never had a problem afterwards so attributed it to something with the head unit or Dension unit. I’ve never had it apart on my 997, but in regular aftermarket amps there is constant 12v but also a separate wire that controls an internal switch that actually turns the amp on. 2x check all those connections. Also, just because there is a light in the fiber doesn’t necc mean it’s sending a good signal. It also could be the DAC aka MOST box. Might be worth gambling $75 to replace that before sending your amp to Becker.

 

FYI my Audio shop, Bangharts in west Chester pa, just let me know the fiber optic interface with the head unit was bad. Apparently it hadn’t been zip tied down when it was installed six years ago. So it was flopping.

new one is apparently $500

bangharts is top notch so I’m trusting them. Fantastic reputation. Nonetheless, that sucks.