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Thread: Meltdown!

  1. #11
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Meltdown!

    No worries. Be careful about changing the grounding scheme though - the 78-series regulators do require some biasing components (as you can see in the application circuits) and if they are not in the moulded dongle then they will be in the monitor unit and/or the camera. The RCA plug shield wire is probably connected to the 12V ground reference within the monitor unit. Just make sure there are no open or short circuits in any of the connections to the plug - the +12V feed, RCA ground and composite video should all be isolated from each other.

    I think in your application the dongle is intended to step down the 12V to the voltage required by the camera unit, like Rick says. You can do this with a linear regulator if the input voltage is within the range of the device and it has the correct output voltage for the application. The mini-DIN plug that connects to your monitor appears to be identical to my system, which runs a 12V camera module (so the regulation is on-board in my case).

    I was hoping you might have a variable power supply handy. You should be able to run the monitor and the camera from independent power supplies, but don't be surprised if the resulting image "rolls" or wobbles - this could be 60Hz mains hum breaking through, which won't be an issue on a vehicle system.

    There's still some fiddly investigation to do, but its looking hopeful. Good luck!

    Lauren
    only Pythagoras can save me now!

  2. #12

    Re: Meltdown!

    Well, I finally made some time to finish testing the backup camera. It's dead Jim... I started with 3.3v, then 5.0v, 9.0v, 12.0v and finally (just for giggles) 15.0v. nothing. after I hit 12.0v the first time up, i switched the RCA output leads and tried again. without any luck, I decided I had nothing to lose by feeding it 15v.

    After finding no life left in it, I decided an autopsy was in order. I could not find anything obviously wrong with it inside; no burned resistors, pinched wires or blown chips. Sigh... I repacked all the parts into it's original little cardboard coffin and unceremoniously laid it to rest on the shelf - right next to the LCD screen I fried with too much voltage. maybe some of the adapter rings will be needed on the next fleabay one I have to buy.

    these cars have EXPENSIVE learning curves sometimes...
    1975 Sterling
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  3. #13

    Re: Meltdown!

    eh...for $19 (delivered) on fleabay I just bought another camera. they sure have dropped in price since I bought the first one! At this price, I can afford to replace them once a year...
    1975 Sterling
    215 ci Buick V8
    Sterling in Garage! Back to work!

  4. #14
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Meltdown!

    Sorry to hear the camera module was fried. It was worth a try before committing it to the big electronic junkyard in the sky...

    Hope you have better luck with the replacement unit!

    Lauren
    only Pythagoras can save me now!

  5. #15
    Senior Member bushboy's Avatar
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    Re: Meltdown!

    Talking about telecams, mine died last night on the way home. Was working one minute, next minute.........no signal was displayed on the blue monitor screen. No time yet to investigate. And I really really miss having it. No rearview mirror, just the wing mirrors giving me a view of the elephant ears sucking in bugs!!!!

    bushboy
    "Always do what you are afraid to do"
    "I can accept failure, but I can't accept not trying"

  6. #16
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Meltdown!

    Oh dear - as you say, not a good time to have a failure, especially on a daily driver. I don't know what I'd do if mine failed, there's no acceptable position for an interior rear view mirror.

    Amusingly, I had a hire car from work the other week. Its the first time I've driven something other than the Nova for over a year and I found it really annoying to drive at night because I kept being blinded by the lights in the rear view mirror!

    I know you can flick the dip thingy, but my telecam compensates automatically...

    (Yes, I know some snazzy Renaults have mirrors with light sensors in them, but this was a cheapo Vauxhall Corsa )

    Good luck tracing the cause of the fault - hopefully its just a loose connection.

    Lauren
    only Pythagoras can save me now!

  7. #17

    Re: Meltdown!

    I just found the "on" button for my mirror and find it works better switched on , never work on a nova just no where to put. The thing the last mirror I had stuck on the windscreen I ripped off as I could not see that side of the road.
    http://jimsnova.page.tl/
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  8. #18
    Senior Member bushboy's Avatar
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    Re: Meltdown!

    Yesterday the TFT monitor also died. so now I am back to square one

    No camer,
    No Screen,
    No rearview

    bushboy
    "Always do what you are afraid to do"
    "I can accept failure, but I can't accept not trying"

  9. #19

    Re: Meltdown!

    Bum - don't you just hate it when that happens? Is it possible the system needs its own voltage regulator to stop it getting the 14 volt charging current? (I seem to remember reading about that when I was fitting mine...........)
    It's a 50 year old car and everything works, just not always at the same time.......and it's probably about to get jealous!
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  10. #20
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Meltdown!

    Man, that is a bummer.

    You're telecam is made up from piece parts, isn't it Martin? I wouldn't be surprised if the monitor supply needed some additional series regulation. The trouble is, most linear regulators need around 2-2.5V of headroom otherwise they drop out of regulation. So the best you could hope to do with a 12-14V vehicle supply would be 9.5-10V regulated. That may not be sufficient to drive a 12V device.

    It does seem a bit odd that both your camera and monitor both failed in succession. If they were both rated for 12V operation, are you happy with the alternator output? Do you have a voltmeter on board?

    I'm just wondering if you have more volts about than the normal 14V limit... It might also have explained the "rolling" picture, which only stabilised when driving at night??? That would obviously coincide with increased electrical demand from the lights...

    Lauren
    only Pythagoras can save me now!

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