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Thread: Xenarc touchscreen flickering

  1. #1
    Newbie OrangePeel's Avatar
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    Question Xenarc touchscreen flickering

    Hi

    I know this may seem out of place, but I don't think it's the screen. My Xenarc 700TS works fine on the AC adaptor in the house, but when I installed it in my car I noticed that there are reasonably faint flicker lines apparent when the screen is displaying something dark. I thought alternator noise at first, since the screen grounds directly through its base into my dash (as well as through its power cable) and the PC is at the back grounded to the chassis. Some experimenting with removing ground loops by hooking it up by a long cable to the PC ground didn't solve the problem at all. Also alternator noise was counted out because it happens with the ignition off.

    I've had it for about 6 months now, and it's more of a slight annoyance than anything else.. I mean I don't care, but sometimes I pick people up who haven't seen my system before and they're like "wow a TV!" then they're like "why's it so flickery?".. hmm wish it was a TV must get a tuner card.. Anyway.

    Yeah well I traced it to the hard drive I think. The whole carputer is currently on an Ituner PW60 with an Epia V8000 and Seagate U series 5400RPM disk. The draw is nowhere near 60W. I have an Opus supply on backorder currently.
    But yeah, whenever the HD is accessing, the screen gets ripples across it. I'm guessing they're being fed down the VGA cable from the motherboard.

    So this is as far as I've got with my assumptions. Anyone know how to isolate the problem? I thought about having a separate power supply for the HD, but that's just inefficient.. Anyone think my Opus might fix the problems when it arrives? My PW60 is annoying because it drops its power good line unnecessarily sometimes, and doesn't stay on while cranking the car. Damn annoying. And yes my car PC has plenty of ground/positive supply, 18awg cable to my amp distro blocks.

    Help?
    89 Celica, CarPC installed, 1st bday :)
    http://www.fishy.net.nz/carpc/
    • MediaEngine
    • Epia V8000
    • 80GB WD 7200RPM HD
    • Xenarc 700TS
    • SB Live
    • Opus 90W
    • CIMR100 remote
    • Deluo serial GPS
    • D-Link USB radio wired to power antenna

  2. #2
    Maximum Bitrate jusatry's Avatar
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    maybe sheild the VGA cable? Shield + ground?

  3. #3
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    i have exactly the same problem. It's "noticable" - though my car is primarily used for music, it does make films look silly in dark scenes.

    I am using a 150W OPUS (3.2 GHz P4) - i had considered if it was HDD accessing, or something too. Have you tried using the 12V cig adaptor that came with the screen, i run mine off the PC 12V line, but should probably try that too, its just, i am tooooo lazy, and it works as it is

    if you do source the problem *please* PM me, i would be greatful for any help

    Stu

  4. #4
    Variable Bitrate Pokey's Avatar
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    I would go with the largest wire (lowest gauge <=10awg) as you can find. 18 gauge is fine for your stop lights, but when you're talking about power supplys you NEED the largest wire you can get ahold of. The larger the better. Remember that the smaller the wire, the larger the voltage drop. You want your power supply (or inverter) to think its sittting on top of your battery. Not to put the fault on anyone here, but i see too many people use whatever wire they have laying around for the battery supply. That wire is the most important wire in a car for a computer. And only use it for the hot wire, use frame as a negative wire.

    Just trying to help out

  5. #5
    Raw Wave Confused's Avatar
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    Wire it up to the regulated 12v from the Opus, and it will be perfect.

    Trust me, i've experienced it.


    Garry
    Co-Developer of A.I.M.E.E
    www.aimee.cc

  6. #6
    Variable Bitrate
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    I am powerin my Xenarc from a regulated 12V supply and it still flickers. The flicker seems proportional to hard disc activity.

  7. #7
    Constant Bitrate StationRocket's Avatar
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    I had the same problem and it turned out to be that the VGA cable was picking up niose off the power cable to the Xenarc.

    I seperated the two cables which I had origionally and together and my niose issue went away. I guess the shielding on the Xenarc supplied VGA cable isn't that good.

    I'm running the Xenarc on unregulated 12v (aka 14.4) off my battery via a relay that is keyed to the ignition.

    I have a 90W Opus powering my Epia M 1GHz, my slim slot DVD/CDRW and a 5.25" hard drive.

    Hope this helps

  8. #8
    Newbie OrangePeel's Avatar
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    I've always had my Xenarc hooked up using the cig lighter plug behind the dash. Problem is my Xenarc has its base screwed into the top of the ashtray inside the dash, which means that it's grounded through its casing (I know this, coz I can touch +12 to the tip of the cig lighter and it comes on without the ground cable...
    So if I use the Opus power, there will be a ground loop. At the moment, the cig lighter ground is pretty much at the same point as the screen is grounding through its base. Of course the PC is at the back, and grounded there.

    So yeah. My laptop's coming back from service tomorrow hopefully, I'll hook it up on that and see if the noise goes away.. I have a feeling it will. If so, I'll hook up my linear regulator molex connector that I hacked up a year or two ago to the HD and power it separately, see what that does...
    89 Celica, CarPC installed, 1st bday :)
    http://www.fishy.net.nz/carpc/
    • MediaEngine
    • Epia V8000
    • 80GB WD 7200RPM HD
    • Xenarc 700TS
    • SB Live
    • Opus 90W
    • CIMR100 remote
    • Deluo serial GPS
    • D-Link USB radio wired to power antenna

  9. #9
    Variable Bitrate
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    Aug 2004
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    I've had this same hard-disk access noise on every Xenarc screen I've installed. I've installed in 6 different vehicles, and no matter how many grounds you add it's still a problem. To minimize it, solder a ground wire to the metal ground on each end of the Xenarc cable, and ground those wires at the same place all your other stuff is grounded too. it still won't go away entirely though.

    Xenarc won't be able to help you either - they dont care the screens still sell.

    the problem:
    - is not there when powered on 120V adapter
    - is still there when powered by a 12V DC-DC converter
    - is still there even with the ignition off
    - seems to come from any kind of MOBO activity
    - has no solution!

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