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Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

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    Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

    This Sony HCD-NE5 (CMT-NE5) compact HiFi doesn't do anything else when pluging power cord: Standby LED blinks about every second (half second on, half second off). Doesn't respond to any button. Doesn't even try to switch the power relay that has to switch main transformer.

    11V standby present, 3.4V go to the IC801 (CPU or system controller), but it doesn't try to turn the relay by outputting 3V at POWER-ON line (IC801 pin 85): 0.0V. Actually, this line has a 50Ω resistance to GND, I think it's too low. I can unsolder a jumper wire near CPU and check that this low resistance is due to the CPU and not to other surrounding component.

    No short tactswitches. 3.4V at one pin of every tactswitch.

    I open POWER-ON line from CPU and put 3.4V from another point: the relay clicks and voltages appear, but nothing else happens. I think the CPU is bad, won't waste more time with this one. I just write this for archival purposes and to be found by others with same problem.

    Don't tell me that it is in audio protection mode. At this phase, the CPU has no way to sense the audio circuit as no voltages are generated, aside of standby voltatge.

    #2
    Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

    if the cpu was dead it wouldnt flash the led.

    you may still have a power issue.

    Comment


      #3
      Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

      I don't mean the CPU is dead, just malfunctioning. It's not a matter of all-or-nothing.

      At this stage, only standby power is relevant, and it's OK. If CPU doesn't even try to activate the relay (RY901), how can it be a power issue? What can disturb CPU from activating this relay?

      I've attached SM in someone wants to analyze the problem.
      Attached Files

      Comment


        #4
        Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

        One thing to check is the ac det circuit, do you have voltage at the input and output of IC803

        Comment


          #5
          Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

          I previously checked Reset signal (11), and there’s 3.4V. There’s 3.2V at one side of IC803 and 3.4V at the other (pinout is wrong in schematic). 3.4V at I_POWER_DOWN (23).

          Comment


            #6
            Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

            reset signal is usually a short low pulse when you turn the power on.

            Comment


              #7
              Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

              It’s amazing. I’ve left this set sitting for two weeks, unrepaired. Now I try it again and it works fine. I’ve tried several times in cold state, always works. Before, it didn’t work not a single time, was a constant failure to me.

              Comment


                #8
                Re: Sony HCD-NE5 (CMT-NE5) repair, standby LED blinking, just this

                Temperature changes "moving" FFCs or other connectors, eventually establishing good contact?

                clean/reseat any FFCs between boards

                use "nutrol" or "2-26" on the fingers, then plug em back in
                "pokemon go... to hell!"

                EOL it...
                Originally posted by shango066
                All style and no substance.
                Originally posted by smashstuff30
                guilty,guilty,guilty,guilty!
                guilty of being cheap-made!

                Comment

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