🚀 go-pugleaf

I have a SOTA VGA/16 board with 512K RAM. Does anyone have information about
this VGA board. It uses a Tseng Labs chip set. Examining the source code of
Bert Tyler's FractInt public domain program I have managed to perform basic
graphic operations in some of the extended VGA modes (ie set mode, read/write
a pixel). However, I have not managed to use the 800X600 with 256 colours mode
properly. Using the method Bert Tyler uses for setting this mode on an Orchid/
STB/Genoa/Sigma board, I get a fractal image drawn in the correct mode, except
a few vertical lines appear in the image. These lines seem to be mapped to
RAM which does not contain constant values since the colours of the lines aree 
constantly changing very rapidly. So the question is am I doing something wrong
or have I got some bad RAM? The diagnostic program that came with the board 
shows everything as ok but I think it only uses the first 256K.

If anyone can help me with this problem or has information about doing such 
things as panning and scrolling on this board, I would be most grateful.

Thanks,
                  Bob.