The bars look like the AEC noise the VIC-II has become notorious for. The reason it's *become* notorious is that it's often more noticeable now in modern displays than it did in the classic days. See, modern display design assumes that you'll be receiving modern signals generated to better standards that yesteryear - from cable TV, recent DVD players, etc - and so their goal is to give a high-definition rendering of that without filtering, attenuating or smearing it as much as older displays did. Hence, the flaws are more noticeable. On an 80s CRT, you'd see them, but not in such eye-popping detail. Still, modern TVs use various methods of decoding and digitizing legacy analog inputs typically with intentional noise filters applied, some of which may hide the AEC noise better than others.banman wrote: ↑Wed Apr 29, 2020 9:34 am I noticed alternating vertical bars. I then reconnected the same C64 setup to an old Pioneer Plasma TV. This Pioneer set has seen better days, some of cells aren't working correctly.
Interestingly I observed no vertical bars. Maybe you can give some thought on this.
The image wasn't as sharp as the Hisense LCD. The Pioneer screen is about 5x larger than the Hisense LCD TV set. This may be a factor at play.
Maybe the issue is as eslapion says a feature of the way TV sets / monitors display the incoming signal......
In both cases I used the RF cable and attempted to tune the sets as close as I could to each other.
Where ever I manually tuned the Hisense LCD TV set the vertical bars were present.
On top of this, you are mentioning that tweaking the RF tuning a bit tends to make the noise more or less visible. This is an artifact of how the RF modulation encodes the composite signal and audio together into a carrier wave. TV's, old AND new, used a automatic gain control to try to make detail visible out of the signal, and sometimes if you tune a little either side of ideal you'll get overamplification of the luma changes (looks like oversharpening) in an attempt to amplify part of the signal the decoder's circuitry sees as 'not good enough.'
Current receivers tend to do a relatively poor job with RF output from old devices mainly because they are more selective and are expecting a stronger and more tightly-tuned input signal, which is why, although it seems paradoxic that the best new stuff would do a worse job with old equipment, it does.