Z32 (Audio/Stereo) Unclean power or electrical interference?

Discussion in 'Technical' started by bobbs, Aug 22, 2019.

  1. bobbs

    bobbs Member

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    Just a small but annoying issue with my 1991 zed- my minidisc player glitches like mad when used in the car, even when the engine isn't running... but is usually worse when the engine is running... And its very intermittent and doesn't seem to be affected too much by temperature.

    But the strange thing is the unit works perfectly fine outside of the car, either hooked up to my lab power supply or directly off a 12v battery. I've opened up the head unit itself, cleaned all lenses, mechanical parts and closely inspected all capacitors and everything seems fine.

    What could possibly be causing this kind of electrical interference? I'm guessing unclean power? For example, it still has a series 1 PTU that everyone says I should replace as preventative maintenance, but no idea if at all relevant. Only other electrical mods are a Nistune ecu, auto to manual swap, turbosmart boost controller, radio frequency step up converter and a crappy compact kicker subwoofer (doesn't matter if connected or not) and faulty clock removed. Oh it also had a break (broken ignition power wire) in the main loom under the front right guard that I bypassed many years ago.

    Any ideas?
     
  2. tassuperkart

    tassuperkart Its a lie I tell you!

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    I would be closely investigation -ive side issues at the power supply to the disk player.
    Load the power supply with a dummy load, a brake light should do, set a digital multimeter to minimum range DC and then probe between the negative connection of the player power supply and the battery earth post. Polarity of the probes isnt important.
    You need to load the circuit, not just probe the power supply unconnected.
    See if you have so strange stuff going on on the -ive side which will show up as any reading on the DMM above zero volts..

    Negative side power supply issues are the main cause of strange glitching in anything electrical so its a very wise move to pay very close attention to earth side cable runs and connections.
     
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  3. IB

    IB ?????

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    Have you connected the dimmer wire? IIRC it works differently to normal dimmers.
     
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  4. bobbs

    bobbs Member

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    Cheers guys. Those are some good starting points.
    IB: That's interesting you brought up the dimmer wire. The player didn't have a dimmer function so It's just left floating. I think it's the same wire that goes to the clock (blown) and dash lights (positive voltage signal?) so I didn't think much of it.
    I think tas might be onto something with the wiring. Even some of the earth points look rusty and I've had problems before with the main loom under the dash. Do you think running new wires directly from the battery would help? (if cleaning all the wire contacts doesn't help)
    I hope to have a look this weekend if I can stop feeling depressed about my zed not running for the last 6 months :/
     
  5. IB

    IB ?????

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    I haven't tried run any new wires for the head unit. I would if I was powering an amp.
     
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  6. Blue300

    Blue300 Member

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    It would have to be a loose or disconnected earth wire from any or all the parts you explained in the post, that would defintly make alot of the electrical circuts go crazy and have a mind of their own because they dont want to share the amps
     
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