CDR23 pcb repair - Source button not working - Rennlist

11-27-2022, 09:49 PM

#1

schwagn

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Join Date: Nov 2022

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CDR23 pcb repair - Source button not working

Hey all! Recently ran into a little trouble with a CDR23 - I had recently purchased a 996 with CDR23, Bose, and a CD Changer (CD Changer was removed by previous owner). I wanted to add a Rennkit BTR3 Bluetooth adapter, and assumed that my CDR23 was already programmed to use it (it was). The problem I was having was that when I pressed the "CD" source button, nothing happened. FM worked, and AM didn't do anything either. The previous owner mentioned that when he purchased the car, the radio didn't work at all - he sent it to Becker NJ for repair, and I assume they didn't find any issues with it. He figured the CD Changer was bad, so removed it and looped the MOST fiber optic cable.

Anyhow - I obtained the car and wanted bluetooth. Ordered the kit from Dave at Rennkit (great customer service btw - he answered a few questions I had about compatibility) and away I went with the install. Hooked the unit up using the unused cell phone power connectors under the center console, MOST adapter, etc.. and put it all back together. Hit "CD" on the head unit and nothing happened. Nada. At this point I wasn't sure if it was an issue with my install, or if the previous owner or Becker had coded out the old CD Changer, or if the BTR3 was bad... I'm new to the car and wasn't sure how it was supposed to work. After a lot of reading and some limited testing on my part, I was ready to go buy a PIWIS tool and re-enable the CD Changer. Luckily I had a brilliant insight - "Maybe you should try inserting a CD into the CDR23!" If it switched to CD mode, that would probably mean that just the CD button is broken. And so I did. Inserted a CD, and the unit switched to CDS and started playing it. Pressed "FM" and it went back to the radio. Pressed "CD" again and nothing.. it stayed on the radio. Therefore, I assumed the "CD" button was bad. (And the "AM" button too.) I found another CDR23 unit on ebay and ordered it, and figured at this point I have nothing to lose by taking this one apart and seeing if I can fix it. So I did. Found an old post somewhere where someone had a similar issue and was able to find some corrosion on the pcb, and I figured that was my problem as well.

Dismantling the CDR23 was fairly simple. The top popped off, and then by removing a couple of screws I was able to pop off the front of the unit. That came apart by removing 4 screws and some clips. I then found some corrosion and a broken trace on the PCB right where the "CD" source button was. Fixed those by soldering in a jumper wire (don't make fun of my soldering job, I'm no expert.) Covered the repaired pcb with a clear nail polish. Put it all back together and it worked! Except for the AM button... I can live without that. I wasn't able to find any more broken traces along the AM button lines, so idk about that one. But I can now select my BTR3 inputs by selecting "CD" twice to get to CDC mode, then disk 1-6 to use the various BTR3 sources. Perfect!

I wish I had waited until I had the correct soldering tools - I was using an old crappy gun that was too hot, and I didn't have any flux, so this job likely would have been easier with the correct tools. (Or something like a conductive pen for pcb repair, etc..) Luckily it worked and I didn't cause any additional damage.

I tried to take pics along the way. Let me know if this helps anyone, or if you have any questions. I'm happy to help. Thanks!

Lenny