Issue with floppy heads hitting surface

Problems with your machine in general.
Post Reply
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Issue with floppy heads hitting surface

Post by Steve »

Hi guys,

I'm doing some maintenance on a Sony MP-F11W. Followed @exxos guide on it, replaced caps and did all the routine stuff. I noticed the heads are actually making physical contact with the floppy surface, thus failing tests. I understand I can adjust the top head with the spring notches, but it seems that the bottom head is actually hitting the disk! There is even a dark line burned into the head that you can see where it has probably been ruining disks for years.

I can't understand how it is physically possible for the bottom head to be touching the surface of the floppy like that. Any suggestions?

PXL_20211011_155345404.jpg
PXL_20211011_155345404.jpg (281.72 KiB) Viewed 1836 times
User avatar
PhilC
Moderator
Moderator
Posts: 6012
Joined: Fri Mar 23, 2018 8:22 pm

Re: Issue with floppy heads hitting surface

Post by PhilC »

@Steve its likely the disk insertion/eject mechanism is worn or bent and letting the disk sit too low into the drive.
If it ain't broke, test it to Destruction.
User avatar
exxos
Site Admin
Site Admin
Posts: 23488
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Issue with floppy heads hitting surface

Post by exxos »

IMHO When you get to messing around with their heads it is the point I just chucked the drive away. I have spent a lot of time messing around with such things in the past to no avail.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: Issue with floppy heads hitting surface

Post by Steve »

Ok yeah.. makes sense. I tried doing a '@GadgetUK164' on it, but no luck.
User avatar
GadgetUK164
Posts: 430
Joined: Fri Jan 04, 2019 2:26 pm

Re: Issue with floppy heads hitting surface

Post by GadgetUK164 »

Steve wrote: Mon Oct 11, 2021 4:58 pm Hi guys,

I'm doing some maintenance on a Sony MP-F11W. Followed @exxos guide on it, replaced caps and did all the routine stuff. I noticed the heads are actually making physical contact with the floppy surface, thus failing tests. I understand I can adjust the top head with the spring notches, but it seems that the bottom head is actually hitting the disk! There is even a dark line burned into the head that you can see where it has probably been ruining disks for years.

I can't understand how it is physically possible for the bottom head to be touching the surface of the floppy like that. Any suggestions?


PXL_20211011_155345404.jpg
They do touch the surface of the disk - that's how most of them work! I don't think I've seen a drive where FDD heads aren't contacting the disk!
My YouTube Channel - www.youtube.com/GadgetUK164
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10464
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Issue with floppy heads hitting surface

Post by rubber_jonnie »

From what I've read, the heads touch the media to read/write, but don't when moving from track to track, so over time they can get dirty.

The black line you're seeing is likely a thin layer of the metal oxide and can be cleaned with IPA and a cotton bud, I've seen it many times.

If after cleaning and servicing it still doesn't work, there isn't a great deal you can do with it.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
User avatar
stephen_usher
Posts: 5578
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: Issue with floppy heads hitting surface

Post by stephen_usher »

rubber_jonnie wrote: Fri Nov 05, 2021 9:50 am From what I've read, the heads touch the media to read/write, but don't when moving from track to track, so over time they can get dirty.

The black line you're seeing is likely a thin layer of the metal oxide and can be cleaned with IPA and a cotton bud, I've seen it many times.

If after cleaning and servicing it still doesn't work, there isn't a great deal you can do with it.
Ah, you’ve been reading about the early floppy drives which had the ‘head load’ signal and solenoid to raise/lower the head. By the time of 3.5” drives this had gone away to save on cost. The heads are permanently on the surface and held there by a spring. When you eject the disk the transport cage lifts the top head/pressure pad off the disk.

Sometimes that residue takes not only IPA but also an extended period of gentle rubbing with a cotton bud or the flat face of a piece of paper to polish the surface if the drive has been left like that for decades. However, if it looks clean and still doesn’t work then it’s bye-bye drive.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10464
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Issue with floppy heads hitting surface

Post by rubber_jonnie »

stephen_usher wrote: Fri Nov 05, 2021 10:03 am
rubber_jonnie wrote: Fri Nov 05, 2021 9:50 am From what I've read, the heads touch the media to read/write, but don't when moving from track to track, so over time they can get dirty.

The black line you're seeing is likely a thin layer of the metal oxide and can be cleaned with IPA and a cotton bud, I've seen it many times.

If after cleaning and servicing it still doesn't work, there isn't a great deal you can do with it.
Ah, you’ve been reading about the early floppy drives which had the ‘head load’ signal and solenoid to raise/lower the head. By the time of 3.5” drives this had gone away to save on cost. The heads are permanently on the surface and held there by a spring. When you eject the disk the transport cage lifts the top head/pressure pad off the disk.

Sometimes that residue takes not only IPA but also an extended period of gentle rubbing with a cotton bud or the flat face of a piece of paper to polish the surface if the drive has been left like that for decades. However, if it looks clean and still doesn’t work then it’s bye-bye drive.
Makes sense they removed it by the time the 3.5" drives arrived. The 5 1/4" drives I have do a similar thing, except the top head has a felt pad that is lifted to remove the pressure.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
User avatar
rubber_jonnie
Site Admin
Site Admin
Posts: 10464
Joined: Thu Aug 17, 2017 7:40 pm
Location: Essex
Contact:

Re: Issue with floppy heads hitting surface

Post by rubber_jonnie »

Out of interest I just watched this: https://www.youtube.com/watch?v=TfEzjcG_0gs

Quite enjoyed it and the drive mechanism is really interesting too.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Post Reply

Return to “HARDWARE ISSUES”