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Unique screen issue.. Thoughts?

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  • Unique screen issue.. Thoughts?

    I made a Mini ATX setup with integrated graphics powered by the M2-ATX.. Im at about 80% of the PSUs power rating with my setup and i currently have a seperate PSU running off an inverter to power the fans and hdd. In my first attempt at powering the screen, i connected it to the 12v rail of the dc-dc psu.. it worked perfectly but i was only testing it and needed to remove the whole system from the car. The final install went without hiccups except that the screen would flicker to black at random intervals. Troubleshooting.. i ruled out refresh rate because of how periodically it was flickering and it would go to black for seconds at a time. I hooked the screen up to my laptop (without removing it or the connecting wires from their position in the car) and directly powered it from my car battery and the screen worked perfectly at its native resolution (640x480 60hertz). Scratching my head i assumed it was a ground loop issue or an issue with the dc-dc psu so i brought it in my house to run it in a controlled environment off a 800 watt psu and the screen still flickered but now it was so bad i could only see the screen for half a second before it would flciker to black for about 3 seconds then repeat. The lcd ran fine the last time I had it set up this way.
    Some tests I did:
    - Laptop screen output + 12v (seperate psu) @ 640x480x60hertz = no issue
    - Integrated graphics + 12v (same psu as computer) @ 640x480x60hertz = flickering
    - Integrated graphics + 12v (same psu as computer) w/ VGA ground @ 640x480x60hertz = flickering
    - Integrated graphics + 6v (same psu as computer) @ 640x480x60hertz = no flickering issue.. very dim screen (adjusting the brightness crashes the screen and makes it reset)
    - Integrated graphics + 12v (seperate psu) @ 640x480x60hertz = flickering
    - Tried all resolutions and refresh rates supported by monitor.. flickering in all of them
    - Absolutely no flickering when a hi res monitor is used no matter the resolution or refresh rate.

    Im at a loss of ideas besides assuming that the video card is somehow incompatible.. it worked flawlessly before though.. Powered the same way but with just a different video source like my laptop outputting the same resolution and frequency causes absolutely no flickering!

    Anyone with any idea as to what I can try and do PLEASE give me your thoughts

  • #2
    my 669 had the exact same problem-- i could run a 629 on the same connections with zero issues. the problem--the controller board in the screen is bad.
    My OLD 2001 Mitsubishi Eclipse GT:
    "The Project That Never Ended, until it did"

    next project? subaru brz
    carpc undecided


    • #3
      The screen is A okay i fixed the problem.. i upgraded the video card and removed the common ground between vga, mobo and the computer case. at first this didnt fix my problem i still had a flicker issue so i hooked it up to the laptop vga out and to a psu i had laying around which i havent hooked up to yet. i still had the flicker which really baffled me so i hardwired the monitor to a 12v car bat and the laptop and it worked. pretty much saying the psu was on its way out. so i hooked the carpc back up and hardwired the lcd to the battery and val ah no more flicker.. so the solution to my problem was a grounding issue or the onboard chipset.. but im leaning towards a ground loop