3 Replies Latest reply on Apr 15, 2020 6:31 AM by msbettyhunt

    Diode identification and car radio repair

    edumcg

      Hello,

       

       

      I'm trying to repair my nissan car radio model: Clarion BTS33

       

       

      The problem began when the fuel volumen line of my car shortcircuited with 12V.  As soon as that happened my radio turned off and never came back again. I sent the radio with some folks to repair it, they replaced some ICs that were burned out but they couldn't replace one specific diode.

       

       

      Right now, when I plug the radio into my car only the screen shows up but it prints nothing. Just a blank orange screen. No audio output no matter what buttons I press.

       

       

      I found the cable on Amazon: https://www.amazon.com/20-pin-Subaru-Headunit-Harness-Steering/dp/B01D9K3L44

       

       

      I also found the user manual of the radio: https://fccid.io/2ABGYBTS33-CLARION/User-Manual/User-guide-2150158

       

       

      The only component that looks burned out is the diode D402. The diode is the same as de diode D403 so I can see the marking is "C308" the 08 is fllipped to the right 90 degress.

       

       

      My plan is to replace the diode but I haven't been able to find a datasheet.

       

       

      I've attached images of the radio and the circuit board. Any help would be appreciated.

       

       

      Thanks!

        • Re: Diode identification and car radio repair
          jc2048

          SMD markings are difficult because of lots of duplication between manufacturers. It might be this [best to trace out the circuit around it and see if it makes sense with the part in there]

           

          https://docs.broadcom.com/doc/AV02-1320EN

           

          both HSMS2823 and HMS282E use 'C3' code [package size is different, so you could tell which by measuring].

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          • Re: Diode identification and car radio repair
            fiddler_in_the_lab

            I would not have to high hopes that replacing that diode will fix the problem.... but as it is an easy thing to do if you (or a friend) have a multimeter and basic soldering skills. So it sure is worth to try.

             

            I did not find a perfect match for the marking code. There are a few dual diodes that start with C3 (or C30). The 08 could be a date code. But in this case you are lucky that there are more diodes of the same type mounted on the PCB so you can measure if the diode configuration is either "common cathode" or "serial" with a multimeter that have a diode test.. You could probably measure directly on the PCB, or de-solder it to be safe. The diode test should also show if it is a schottky or silicon diode.

             

            I do think that it is enough to replace the diode with any general purpose diode that have the same configuration and type (eg common cathode schottky in sot-23 package) to see it it works.

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