Thanks for the reply Simbo
I’ve check the manual and it states that the 520ST uses single-sided, double density; 135 tracks per inch. It also states that the maximum storage capacity is 360kb per disk. The disks I have used to test it are original st game disks, captain blood, street fighter, weird dreams and more. All seem to be in good condition
I should have been a bit more specific in my first post. Is it most likely that the 3 bomb/address error is related to the floppy disk drive? Or could it be something else? I don’t really want to repair or replace the drive only to find that it hasn't solved anything.
I have got an old 'Sony MPF920-E' drive out of a PC which I could use to replace the internal Atari floppy drive. I see quite a few people on this forum have used the same or a similar model, but the PCB pictures seem to differ quite a bit from mine, in particular, mine doesn’t have jumper pins on the back. Am I right in thinking that changing the jumper setting is all I have to do to get the drive basically working in the Atari? I think I can find the solder points on the 'Sony MPF920-E' PCB for the jumpers, are they labeled JC30 and JC31?
Sorry if I'm asking too many questions, but I have searched the forums for a good guide on this but not really found a clear one. Probably more to do with my general lack of skill in circuitry and forums.