If you didn't disable the 10NES (and installation of CopyNES didn't require it), shouldn't you be seeing a blinking screen if it's just the connector going flaky? If it's a solid screen and garbled graphics with an intact 10NES chip, chances are you're looking at some other failure--possibly the CopyNES, but based on another thread I've been reading over the last few days, also possibly RAM or the PPU.
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Need Stadium Events + Panesian titles, 6-in-1's, Menace Beach, Moon Ranger & Secret Scout to complete my licensed/unlicensed sets.
If you've got any of the above for sale, hit me up!