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Thread: ATI Rage Pro 3D All In Wonder Video Problem (Continuation)

  1. #1

    Default ATI Rage Pro 3D All In Wonder Video Problem (Continuation)

    OK, some of you might remember that I had a problem with my ATI All In Wonder Video card a few months ago: http://www.vcfed.org/forum/showthrea...-Video-Problem

    Unfortunately, I haven't been able to fix it.

    I've decided to bite the bullet and record the problem that I am having with my system:

    (Most of what I'd put here in the post is already in this video)

    Last edited by T-Squared; October 30th, 2017 at 06:24 PM.

  2. #2
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    Alright, curiosity has me.

    Get a multimeter and poke at the RCA jacks on the VCR. IS there any resistance between the tip and sleeve? Does this value differ compared the input jack on the back of the VCR?

    The video card seems to be doing its job. The video card is not the problem (The video card is NOT the problem). At POST there are no system drivers running. Purely the system and the VGA BIOS have arbitrated with eachother. The only thing I can think of is that when the video card comes up it needs to sense a resistance on the signal wire relative to ground ("Oh, there is something plugged into my composite out connector!"), otherwise it simply does not enable that video out mode. For some reason the front port on your VCR is being detected but the back is not.

    Otherwise all the other things I can think of are far more off in la-la land like devices being plugged into two different halves of an AC phase, ground loops or an excessively high AC leakage current.
    Last edited by NeXT; October 30th, 2017 at 08:27 PM.
    = Excellent space heater

  3. #3

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    Quote Originally Posted by NeXT View Post
    Get a multimeter and poke at the RCA jacks on the VCR. IS there any resistance between the tip and sleeve? Does this value differ compared the input jack on the back of the VCR?
    Yes, there is a difference. With the front jack, the resistance is at approximately 75Ω, and stays there. (It sounds familiar and normal to me, as that's the normal resistance for a TV antenna.)

    With the back jack, it SEEMS there is no resistance, at least from what I could measure. (I did get some MegaOhm resistance measurements, but I don't think I was measuring it correctly for those instances.)

    I HAVE tested the back jack with a plug-and play arcade system I have, and it works just fine, but it probably doesn't have a sensing circuit like the ATI possibly has.

    I'll check the bottom of the VCR board again tomorrow morning to see if there's a short somewhere there shouldn't be.

  4. #4
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    I actually edited out of that post saying that you should expect a 75 ohm resistance, but I felt that might send across the idea that this was to be expected when really I did not know.
    However if the front has a 75 ohm resistance but the back does not, because you are not using BNC cabling you cannot just add in a 75 ohm terminator with a T coupling, so find a way to get 75 ohms tied between the signal pin and ground. This can be as simple as a resistor. I'm willing to bet if you just soldered a resistor between the pin and ground on the video card's RCA jack you could permanently force the composite out to always be enabled.

    I'll check the bottom of the VCR board again tomorrow morning to see if there's a short somewhere there shouldn't be.
    IF there was a short the resistance would be lower than 75 ohms.
    I mean, typically when I deal with simple CMOS logic circuits 75 ohms is pretty damn close to a short, compared to say, 1K ohms, but it works for composite video but if the resistance drops things rapidly start to get screwy. If you had a short between signal and ground you would see nothing. It simply would never work. what I'd look for instead is either an out of value or missing resistor, possibly an RCA jack that has seen a little too much use and has been bent out of shape.
    Last edited by NeXT; October 30th, 2017 at 09:47 PM.
    = Excellent space heater

  5. #5

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    What's really making this whole thing weird is that it WAS working just fine beforehand! I was able to use the VCR as a video passthrough+recorder with no problems whatsoever.

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