archive.worldofdragon.org

Hi all,

I recently acquired a Dragon double disk drive and controller with DragonDos 1.0.

Both drives were spinning up but any time I tried a disk command I got an SK error.

Fellow forum member Stig has been trying to help me on the Facebook page but now we have run out of ideas.

Current state of play is that neither drive now spins up and no lights. I have obtained another psu and tried to power up the drives with this but both are still dead. Do the drives themselves have any sort of fuse that may have blown? I am unsure where to go from here.

Thanks guys!

I've had similar proble ms with two drives and ended up being a disk controller calibration issue.

You'll have to try to put the WD2797 chip in calibration mode and use an oscilloscope to properly adjust the variable capacitor on the controller.

Also - check that the drives themselves are not belt driven - I know a large number of original Dragon Data drives were - the belt will be knackered by now and need replacing.

Hopefully you have made a record of any changes so you can back track - you can power the drives from cheap chinese +12/+5v PSUs or a PC ATX PSU - the power connector is pretty standard.