Any chance of saving this FDS disk?

Started by togemet2, February 24, 2023, 10:11:31 pm

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I recently bought a white prototype Famicom disk, but unfortunately it seems to be acting up a lot. The disk itself manages to boot, however, the outcome is always the same. Random colors that continue to flash on screen before it then throws an Error 24 (Disk card header block #$03 unrecognized).

Looking at the magnetic disk shows that both Side A and Side B are very clean, with no visible irregularities. Attempting to dump it several times gives different results: some dumps being completely corrupted, and some showing signs of mostly intact graphic data. From this I was able to determine that it contains a prototype of Otocky.

Could the data be salvageable? No doubt that developers would rewrite these disks using their own development setup, which is why I think this could be calibration related. Any ideas? Thanks!


Well, if you're suspecting calibration issues, you could try slightly adjusting the spindle position and/or speed of the motor until the disk could be properly dumped?


You have three adjustments: spindle alignment, read head position, and motor speed.

the guide for correctly aligning the spindle is here:

If you have a scope, you can use it to set the read head at a position where the signal is strongest using this guide:
you can also try doing this with a good digital caliper.

motor speed can be tuned with the copy master program:
I believe a speed of 4-5 should be optimal when a disk is inserted.

good luck. if you want to sell it afterwards, let me know.


Thanks for the links, fingers crossed everything goes smoothly!

Will update if I can get anything working.