tendril
Well-known member
Does anyone have the bootleg marked 'CAT NO. K70' ? If so, I'd appreciate some pics of both boards to see how they compare to mine
I got this board a while back as not working, and found corroded tracks, warped pcbs, liquid damage to the ROMs/sockets. I thought it was otherwise complete though, but I'm beginning to wonder if a previous owner stripped it for parts, making my job even harder.. There's no capacitors/diodes on any of the inputs. On the bottom board, no pull-up resistors on the graphics ROM data bus. Smoothing caps seem to missing. So I'm not sure if this was a previous owner, or the bootlegger REALLY cut corners in getting this out there. Another interesting difference is a 27c512 has been used in place of two 27c256's - both for the main program, and in the graphics. I've already found bad TTL chips on both boards, but all I've ever got this to display are green lines (palette ram and related are tested good though).
I'm concentrating on fixing the video board to display something other than lines by running with the main program ROM removed - on the assumption this should actually display proper random tiles. Can anyone with a bootleg or original actually confirm this though (pic?
) The reason for this approach is I don't know if the CPUs are running properly at all, but they certainly clear the graphics memory early in boot, which doesn't help to debug the graphics.
So if you do have a board, just pull the program ROM that you can see missing in my pic and see what happens
I got this board a while back as not working, and found corroded tracks, warped pcbs, liquid damage to the ROMs/sockets. I thought it was otherwise complete though, but I'm beginning to wonder if a previous owner stripped it for parts, making my job even harder.. There's no capacitors/diodes on any of the inputs. On the bottom board, no pull-up resistors on the graphics ROM data bus. Smoothing caps seem to missing. So I'm not sure if this was a previous owner, or the bootlegger REALLY cut corners in getting this out there. Another interesting difference is a 27c512 has been used in place of two 27c256's - both for the main program, and in the graphics. I've already found bad TTL chips on both boards, but all I've ever got this to display are green lines (palette ram and related are tested good though).
I'm concentrating on fixing the video board to display something other than lines by running with the main program ROM removed - on the assumption this should actually display proper random tiles. Can anyone with a bootleg or original actually confirm this though (pic?
So if you do have a board, just pull the program ROM that you can see missing in my pic and see what happens
