jonb wrote: ↑
Mon Jan 14, 2019 12:09 pm
Returning to the first picture, there are still problems:
- Top line missing
- Half of the bottom line is missing
- The monitor sometimes struggles to lock onto the signal (despite me fiddling with the trimmer on the little composite board)
Mark, you mentioned on your other thread that the position and size of the output could be adjusted. I guess that is not possible with this setup and one would need the GBS-8200 board as well? I do have one lying around but I was saving it for the Amiga 1200.
That was by using the settings / controls on the GBS-8200 board.
With all analogue video systems, keep in mind that television (4:3 aspect ratio) always has an image that is biggger than the available screen area, so that the viewer does not see any black borders. So all analogue CRT sets have appropriate technicans controls (and sometimes user controls) to set it up like this (assuming the received signal is within the specification).
But for computer monitors, the size of the generated video picture should either be the exact right size, or have border areas. But not all computer manufacturers stayed within the specification for broadcast video. So the monitor has to be matched to the system. Most CRT monitors also have appropriate technican controls or user controls, or both. But most LCD displays have limited controls, as they were designed to work with signals that comply with broadcast video specifications.
So if the display you are using does not have enough range in the controls available, the first step is always to try another display. The only other solutions are to see if the timing of the computers video system can be changed, or to use a scan converter like a GBS-8200.
Note that some LCD displays don’t display the top line or bottom line of a BBC or Master. And nearly all don’t display the left hand and right hand side of the image generated by a QL in monitor mode.