Got a HB-F5 a while ago from Japan. The image however was just garbage. The AV-out was so blurry that even in 40 columns you could not read the text. The RGB output from the JP-21 connector (Scart like) was not much better due to a poor sync signal.
I put the thing away, but started tinkering with it a few weeks ago and now have a beautiful image. As it turns out, the RGB potentiometers were all the way turned up, causing super saturation of the image. That still did not clear up the sync issue. I tapped directly into the sync signal from the LVA510 composite video encoder IC and fed it together with the RGB signals into a GBS8200 RGB to VGA converter board.
The result is phenomenal.
https://drive.google.com/file/d/1fvR-C3gP4auatwinSGr6-T9dIFL...
https://drive.google.com/file/d/12zycfYUIy86asNaogpnkJhBOU_E...
https://drive.google.com/file/d/1x58HLIeAf8ZbxbMq7TJ3-DbgvTA...
