Dragon 64k PAL Video Schematic

[Rinconete]

See "Video Problem" topic in the General subforum

[Rinconete]

Dragon 64L PAL Video Schematic v3

Corrected some minor typos.

The schematic has been captured using the open source tool KiCAD. The shape of most of the parts has been redesigned to match the look of the Dragon Data schematic and included in a lib file. Although I have checked each part, line, ref and value against the original schematic and the PCB, using a multimeter, the schematic is provided 'as is'. Since I am unable to read the capacitor values they are not specified.

Some minor differences between the Dragon Data schematic and the PCB have been found. All of them are documented by means of text notes at the specific places.

I would like to thank mcleod_ideafix, sixxie and Alastair for his unvaluable support on fixing my Dragon 64 by providing some definitive documentation and suggesting some clever hints that led me to the fault.

[sixxie]

Thank you very much for this - it's bound to become useful some day!

[zephyr]

Thanks Rinconete!

[Rinconete]

Dragon 64L PAL Video Schematic v4

Update. Fixed some errors that I had fixed in a previous version but, for some reason, appeared again in v3. It seems to be related with library management in KiCAD. Sorry for any inconvenience.

[prime]

That is most excellent.....humm wonder if I could use bits of that circuit to make a colour board for my Acorn Atom clone (or the original Atom come to think of it) as they both also use the 6847 VDG.

Cheers.

Phill.

[Rinconete]

Most of the video signals come from the MC6847 VDG and only a few come from the MC6883 SAM. If both computers use the same Motorola chipset you could use the same circuit to add the color burst to the video composite signal. Do you know if it has a SAM?