Hot Becker Radio

Discussion in 'Electronics' started by brucemillar, Jun 20, 2017.

  1. brucemillar

    brucemillar MB Club Veteran

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    Folks

    My Becker Radio gets very hot when on. I do mean very hot. I have the radio out of the dash just now as I was attempting to diagnose a speaker fault (now fixed). I noticed that the metal on the radio itself is really hot almost too hot to hold. Is that normal? What could be the cause?

    It is not blowing fuses and is playing okay. Oh it has the built in CD Nav with external nav antenna.
     
  2. Doodle

    Doodle Hardcore MB Enthusiast

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    There's a lot of electronics in there, including a amp...that all generates heat, and it has to go somewhere. The chassis acts as a heatsink, you'll often find a small fan mounted on the back too.
     
  3. OP
    OP
    brucemillar

    brucemillar MB Club Veteran

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    Thank you Doodle. That puts my mind at ease.
     
  4. OP
    OP
    brucemillar

    brucemillar MB Club Veteran

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    Folks

    The issue I am trying to fix is my speakers are muted - as in no sound output - not the head unit muted.

    My car originally had the rear speakers with the fader switch in the center console.

    I now have no rear speakers.
    I have removed the fader switch.

    In removing the fader roller switch I just unplugged the switch from it's base and used thin wire to jumper across the switch base terminals (crude but it works) or it did work.

    I now get sound from the fronts - Good. BUT... Every now and again it simply cuts out.

    This seems (could be anecdotal) to happen when I fiddle with the fader switch base.
    Am I better of just removing this and connecting the wires with solder and heat shrink?
     
  5. grober

    grober MB Club Veteran

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    https://forum.allaboutcircuits.com/threads/damaging-amps-with-wrong-impedance.93669/

    Because older Mercs tend to be fitted with speakers with odd impedances and your wiring is non standard its possible there's a mismatch between speakers and amp/headunit. The result of this might well be the headunit running hot. This would normally be expected to be focussed at the output transistors but could be manifested anywhere from the unit power supply to the output circuitry.
     
  6. OP
    OP
    brucemillar

    brucemillar MB Club Veteran

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    Well it seems that it was a combination of previous bodged wiring and the fader switch.

    As I am not using rear speakers I cut out and insulated the fader switch and wired the front speakers directly to the Euro connector then into the head unit.

    All working and not getting very hot.

    Thank you gents for your help.

    Bruce

    Sent from my iPhone using sausage fingers.
     
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