Quote:

cable works fine, my VCR works fine but for some reason my DVD player causes the vertical hold to go wild.

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So, if I play a DVD every 5-10 minutes the picture slowly scrolls down/upwards across the screen.



This (and your brightness issues) sound like symptoms of Macrovision going overboard, as detected and displayed by the TV. I can't speak for why the VCR isn't causing the same symptoms, but it seems as though the TV is receiving something from the DVD player (when connected directly, or shunted through the VCR) that the VCR itself isn't putting out as of yet.

What you're describing matches exactly what I've seen several years back when people were trying to copy rented movies from one VCR to another, and then tried to play back the copy on their TV.

As a test, try putting an original copy of a Disney VHS tape into the VCR, connecting RCA cables from the VCR to the TV, and watching what the TV does during playback. Disney VHS tapes were famous for containing tons of copy protection signals embedded on them. The point of this test is to see whether known copy-protection-heavy tapes make your TV do the same thing the DVD is doing now. For consistency's sake, you should also run the VCR's RCA cables through the same inputs on the TV as you have been using for the DVD player.

If this is indeed your problem, there are little boxes you can buy that sit between an AV source (VCR, DVD player) that strip out the Macrovision signal. Some are called "video stabilizers", other devices that will do the same job are "time based correctors".
More info here...

I see several different boxes on eBay ranging between $20 and $200 US$. The cheapest fix for you may be to try different DVD players or other RCA video output sources, if you want to keep the TV.