Chinon FB-354 bad upper head

bitrot · 23 May 2022, 17:26

He all, in the process of restoring an A3000 with battery damage.

One of the last of two issues is a floppy drive that I have diagnosed as having a bad upper head.

I have replaced all the caps, lubricated rails and worm gear, cleaned heads.

When inserting the disc, the head will go to track 0, read the info that has the disks name, etc. So the amiga recognizes it.

I have a second drive in there that works 100% so I know it is not cabling or jumper issues.

I used a diagnostic tool and it can read every sector on the lower head and nothing on the upper head.

Anyone have an experience if there could be something else on the PCB that could be bad?

Contacts for the head ribbons are clean. Is this a spare parts drive now?

Any advice is welcome. Thank you.

whaka · 04 June 2022, 02:02

hello,

dead head can happen too, if the coil get burnt due to a defective head amplifier.
what you can try is simply connect the lower head ribbon on the upper head connector and see if it can read something.

in the better case, this may work and confirm a dead head.
in the worst, you'll fry the lower head too, and you'll be fixed...
at this point there's not really a lot to loose anyway.

Bruce Abbott · 04 June 2022, 02:45

Most common reason for a bad head is wires pulled off it due to it getting caught in a floppy disk case when being ejected. In my experience this was impossible to fix, so the only repair option was to take a good head out of another (faulty) drive.

I wouldn't bother doing this today because I no longer have a stash of faulty Amiga drives, and old PC drives are cheap and readily available.

23 May 2022, 17:26	#1
bitrot Registered User Join Date: May 2022 Location: USA Posts: 3	Chinon FB-354 bad upper head He all, in the process of restoring an A3000 with battery damage. One of the last of two issues is a floppy drive that I have diagnosed as having a bad upper head. I have replaced all the caps, lubricated rails and worm gear, cleaned heads. When inserting the disc, the head will go to track 0, read the info that has the disks name, etc. So the amiga recognizes it. I have a second drive in there that works 100% so I know it is not cabling or jumper issues. I used a diagnostic tool and it can read every sector on the lower head and nothing on the upper head. Anyone have an experience if there could be something else on the PCB that could be bad? Contacts for the head ribbons are clean. Is this a spare parts drive now? Any advice is welcome. Thank you.

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04 June 2022, 02:02	#2
whaka Registered User Join Date: Jan 2017 Location: France Posts: 102	hello, dead head can happen too, if the coil get burnt due to a defective head amplifier. what you can try is simply connect the lower head ribbon on the upper head connector and see if it can read something. in the better case, this may work and confirm a dead head. in the worst, you'll fry the lower head too, and you'll be fixed... at this point there's not really a lot to loose anyway.

04 June 2022, 02:45	#3
Bruce Abbott Registered User Join Date: Mar 2018 Location: Hastings, New Zealand Posts: 2,544	Most common reason for a bad head is wires pulled off it due to it getting caught in a floppy disk case when being ejected. In my experience this was impossible to fix, so the only repair option was to take a good head out of another (faulty) drive. I wouldn't bother doing this today because I no longer have a stash of faulty Amiga drives, and old PC drives are cheap and readily available.

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