SE/30 floppy drive won't write or format

[samb]

I'm having an issue with a recapped SE/30. Post recap and ultrasonic cleaning, the logic board works flawlessly, except for the floppy drive. The drive works fine as a boot drive and can also read floppy disks without any issues; however formatting ANY disk fails (400K, 800K, 1.4M) .

When formatting on an external 800K drive, the formatting portion completes and the disk is ejected, with a "failed to initialize", just before the verification pass starts.

With an internal drive, again reading the disk (and booting from it) works fine, but formatting the disk freezes the computer with a "type 11 error".

I've buzzed the traces between the SWIM, the internal floppy header and the external floppy connector - all check out fine.

Any idea as to what may be causing this behavior?

Thanks in advance for any help or pointers anyone can provide.

 

[shirsch]

You mention it booting and reading diskettes. Can you write to the diskette?

 

[jmacz]

I had a similar problem. Check this thread for what the issue was in my case:

Post in thread 'Floppy / Floppy Controller SWIM Issues'
https://68kmla.org/bb/index.php?threads/floppy-floppy-controller-swim-issues.42355/post-521513

 

[samb]

You mention it booting and reading diskettes. Can you write to the diskette?

It won't write or format diskettes, but reads them flawlessly.

 

[samb]

I had a similar problem. Check this thread for what the issue was in my case:

Post in thread 'Floppy / Floppy Controller SWIM Issues'
https://68kmla.org/bb/index.php?threads/floppy-floppy-controller-swim-issues.42355/post-521513

Very interesting thread! Thank you. I'll take a look at uh7 later tonight or tomorrow.

 

[samb]

@jmacz thank you so much for the linked thread! It turns out that I have EXACTLY the same issue: a metal probe on UH7 pin 4 and all of a sudden formatting works perfectly.

I admire your perseverance and thanks for the very thorough investigation and write-up.

I need to determine what would be the best way for me to deal with this: UH7 replacement or a single gate inverter. In the meantime, I've used a capacitor of 2pf to ground and it's working great.

 

[jmacz]

@jmacz thank you so much for the linked thread! It turns out that I have EXACTLY the same issue: a metal probe on UH7 pin 4 and all of a sudden formatting works perfectly.

I admire your perseverance and thanks for the very thorough investigation and write-up.

I need to determine what would be the best way for me to deal with this: UH7 replacement or a single gate inverter. In the meantime, I've used a capacitor of 2pf to ground and it's working great.

Awesome, glad it helped!