Turn on after 3 seconds turn off

Discussion in 'General Electronics Chat' started by donskiter, Dec 2, 2006.

  1. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
    I went to my friend he ask for my help if i can repair his kenwood model RX-39 audio system. I turn on the power then it seems the unit have no problem but after 3 seconds the unit turn off and the message appear on the display ( Protect )..I noticed after repeatedly turn on i hear a clicking sound inside the unit before the unit turn off..I plan to open it by next week so that i can first gather informations before i try to repair it.

    By the way... My friend told me that sometimes he can used the unit for a couple of months when he will not used the unit for a weeks then after the unit will fail again then he will not used the unit for a weeks..... it seems that the unit is working if had taken a rest
     
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    Protection fault normally means either DC present on a speaker output (faulty amp channel) or excessive load on an amplifier..(incorrect/faulty/too many speakers or faulty speaker lead).
    The clicking is just internal relays.
    If you are not sure about it, I would suggest first checking to see if it still does it with all the speakers disconnected. If the answer is Yes, then take it to a pro.
    If it is fine with speakers disconnected, then check the speakers/leads and loading.

    My gut feeling is a crook amplifier output device(s).
     
  3. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
    Hi Guys…

    I just came to my friend place yesterday to repair his audio system with full of knowledge thru the tips I gathered to all of you guys ( Checked for cracked solder joint, speaker wiring, failing capacitors in the protect circuit... I confirmed that when I checked his audio before theres no speakers connected so I plug the cord on the outlet and turn it on again same as before the unit shut off after 2 to 3 sec, I cleaned the connector by tipping using my finger to cleaned the connector outlet before we connect the speakers on the unit then we turn it on the unit does not shut off so we play a cd to test its working! But we noticed that when we turn up the volume the unit shut off( protect) so we try it again to know what level of volume the unit shut off its seems that the unit seems working if only set below 35 ( note. Max volume 60 ). After that we dismantle the unit to check the components of power supply hoping to find fail components by visual check up then and again slap a little the connector pin of the speaker to cleaned hoping to remove the one that causing the shut off if any . After we assemble the unit we connect the speakers and turn it on its working so we decide to turn up the volume above 35 the does not shut so we adjust it to 40,45 and 50 the unit does not shut off. Im happy that I successfully fixed his unit. But Im confused what really the caused why that unit behave like that?????? and How I repaired that ,I only disassemble the unit?????

    Don
     
  4. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    Normally shutting down as the volume is raised is caused by excessive speaker load. I also struck a Panasonic stereo that also did this because as the volume was raised, an internal Cooling fan that was suppose to come on had gone faulty, tripping the protection circuit.
    Not sure what is causing your problem.
     
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