SE/30 crash when writing to floppy

[Jamieson]

SE/30 in good shape, logic board recapped, generally it's working well. It can read floppies fine, it can boot from a floppy no problem. But when I try to write or format a floppy I get the bomb and am forced to restart. The floppy drive has been throughly cleaned and lubricated, and heads clean, etc. Does this sound like drive problem or a logic board / SWIM problem?

 

[Garrett]

I had a similar problem with SCSI devices on my SE/30. Turned out to be one disconnected trace from the SCSI chip. I bet if you probe around your SWIM you'll find a broken connection somewhere.

 

[Jamieson]

So far all signals between the SWIM chip and the floppy ribbon cable connector are checking out OK. Could be something between the CPU and SWIM, but it's strange that it reads OK. Time to check the connections between swim and the CPU...

 

[Paolo B]

Hi All,

I post my lines here, just to avoid creating too many threads.
Issue: in one of those stupid moments which unfortunately are part of any tinkerer experience, today it just happened that I made a totally idiotic thing and apparently I busted something on my beloved SE/30 logic board.
Root cause: I connected an external “naked” floppy and didn’t notice the metal cage I used as stand up was actually shorting the floppy connector on the logic board side. Yes, very stupid. So, when I powered the Mac, after the first “boing” it instantly rebooted, because of the short. As I realized the issue, I immediately switched it off, but it was too late.
The floppy drive is still OK (tested working with some other Mac), but when I attach it to the SE/30 via the external connector, I get some weird error, like “Can’t format this disk, as it’s write protected”, even If the floppy is empty. So, something got busted. The good news, though, is that when I connect the floppy to the internal connector, everything works fine. So, I would guess it’s not the SWIM chip that got busted, but it shall be something upstream the internal floppy connector, which narrows down the possibilities to the filter circuits RP10.
Either way, I may have access to a donor board, but before starting pulling chips and stuff, I’d appreciate having the opinion of real experts about any other potential cause of failure.

Thanks in advance for your feedback!

 

[retr01]

SE/30 in good shape, logic board recapped, generally it's working well. It can read floppies fine, it can boot from a floppy no problem. But when I try to write or format a floppy I get the bomb and am forced to restart. The floppy drive has been throughly cleaned and lubricated, and heads clean, etc. Does this sound like drive problem or a logic board / SWIM problem?

Hi @Jamieson!

Since the LB (logic board) and SWIM seem fine, do you have an external floppy drive on which you can test formatting? If you can format it on an external drive, I am wondering if you can swap out the floppy drive with another internal one and try it?

I am thinking of something mechanically that prevents the internal disk drive from formatting the disk. I know it checks for something, such as whether or not the disk is locked physically, before formatting.