Mega Drive / Genesis jailbars (vertical stripes on RGB video)
Faint vertical bars across the picture, most visible on flat colours over RGB, are interference from the colour subcarrier and other noisy signals on the Mega Drive board. Rule out cables and grounding, refresh old capacitors, then lift or switch off the subcarrier, or fit a subcarrier bypass board if you need to keep composite colour.
Written by the CircuitScope research team in our own words, from the sources listed at the end, and checked by our moderators.
Faint vertical bars across the picture, most visible on flat colours over RGB, are interference from the colour subcarrier and other noisy signals on the Mega Drive board. Rule out cables and grounding, refresh old capacitors, then lift or switch off the subcarrier, or fit a subcarrier bypass board if you need to keep composite colour.
Difficulty: Hard · Time: about 2 hours
Symptoms
- Evenly spaced faint vertical stripes ('jailbars') over the picture, easiest to see on large flat colours such as blue skies
- Worse on RGB through a modern scaler or a professional monitor than on a consumer CRT
- Bars that change in visibility with scaler phase settings
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