Resolved Disk II Drive Read/Write Error (1 of 2 fixed)

Discussion in 'Apple Collectors' started by tevion5, Jun 29, 2014.

  1. tevion5, Jun 29, 2014
    Last edited: Aug 19, 2014

    tevion5 macrumors 68000

    tevion5

    Joined:
    Jul 12, 2011
    Location:
    Ireland
    #1
    I have a 64K Apple II Plus and 2 Apple Disk II Drives. The first drive came with the computer from the previous owner. He reported that before he shipped it, that it was working perfectly and he had pictures to demonstrate this. However, upon the Apple II's arrival in Ireland from the UK, it no longer seems to be able to read any of the 20+ disks that it came with. When trying to boot from any disk it makes a series of rapid clicking sounds for about 20 seconds before giving up and going idle. When I use any drive utility software (booting from SD card adapter), it gives me a "RWTS READ ERROR (40)" when I try to initialise a scratch disk or calibrate speed or anything.

    I opened it up and fiddled about to see if I could find any obvious flaws. One thing I thought was strange was a white circular turntable below the the disk and under the lens. It seemed to have a little needle on it like an record player but it kept skipping off. This was the cause of the constant revving sound the drive gives when I insert a disk. It just keeps clicking really quickly instead of going to the usual "zzzt zzzt click zzzt" that should accompany these drives. I recorded a video of the drive in operation while partly disassembled to show what is happening when it is reading.

    Thinking the drive was faulty and that I was in over my head, I purchased a second DISK II drive, this time from the USA. Same story again. Same errors, same problems. I would think that perhaps the interface card is to blame, or possibly the system itself, but...
    It works perfectly when I bootstrap ProDOS 8 with ADTPro via audio cables and also boots perfectly from an awesome Bulgarian SD card drive that plugs straight into the Disk II interface card like a real disk II.

    I am really annoyed that neither of my drives work at all. I have taken them apart, and cleaned them both thoroughly inside and out, including the "lens" on each.

    A video of my problem can be seen here.


    Any help at all would be GREATLY appreciated, thank you! :D
     
  2. MacTech68 macrumors 68020

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #2
    I'd suggest disassembling the head carriage rails and giving them a good clean.

    There are two silver rails that the head assembly slides on. Once you undo these, use a cloth and some cleaning agent to clean the rails.

    Next, take a cotton bud and a cleaning agent, and clean the holes in the carriage that those rails pass thru.

    Re-assemble the drive and avoid the temptation to lubricate the rails.

    Also, check that the "Load Button" hasn't fallen off the head carriage. The small arm that sits on top of the head should have a little round felt pad that sits against the top of the floppy disk when a disk is inserted. If it's missing, you're in trouble. Sourcing one might be problematic.
     
  3. Coug-it macrumors newbie

    Joined:
    Aug 26, 2009
    #3
    The old Apple II+ system that I had required speed adjustment of both of the
    drives about once a month to get them to read the disks after owning it for
    several years. I recall having a diagnostic disk that would display a slider that
    you had to center after removing the drive case and adjusting a small
    potentiometer inside the drive. Sorry, no more details as its been about 20+
    years since I used it the last time...
     
  4. MacTech68 macrumors 68020

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #4
  5. tevion5, Jul 12, 2014
    Last edited: Jul 14, 2014

    tevion5 thread starter macrumors 68000

    tevion5

    Joined:
    Jul 12, 2011
    Location:
    Ireland
    #5
    Indeed! I'm over the moon. Having bought 2 drives, it's nice to have one that actually works! :D

    Yes, the original drive I had was filthy clogged on the rails. Took it apart, cleaned everything and lubricated the lot again. Works perfectly now.

    The other drive slides perfectly along the rail, but desires to go the wrong way on startup like a stubborn child. As in, the moving slider keeps trying to go toward the back of the drive instead of forward from the rest position. I don't get what it's trying to do. Just goes the wrong way and bumps into a barrier 20 times and gives up. Never goes the correct direction.

    Also, does anybody here know how to boot from a secondary drive?

    Thanks for the help so far.
     
  6. MacTech68, Jul 12, 2014
    Last edited: Jul 12, 2014

    MacTech68 macrumors 68020

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #6
    I would try swapping the analog board on the drive - only temporarily - to see if the stepper motor driver (the ULN2003) and associated circuit is ok.

    Don't leave the boards swapped permanently. This is just to eliminate the analog board as a cause.

    If the drive still behaves that same way, I'd suspect the stepper motor has a failed winding, or the stepper motor or track zero stop is slightly miss-aligned.

    Without an alignment disk, the alignment utility and an oscilloscope, alignment is hit and miss and could cause problems with disk interchangeability.

    AFAIK, there is no method for booting from the DISK 2 on a Disk Controller Card. PR#X (X being the slot the card is installed in) only boots from the DISK 1 position.

    The IIc could boot from the external drive by using PR#7 - but that appears to be a unique feature of the IIc.

    EDIT: you might be able to rig a switch to swap the drive select (pin14) from the Disk1 to Disk2 positions.
     
  7. tevion5 thread starter macrumors 68000

    tevion5

    Joined:
    Jul 12, 2011
    Location:
    Ireland
    #7
    Just noticing now you mentioned not to lubricate the rails....
    Why exactly should I not?
     
  8. David Schmidt macrumors 6502

    David Schmidt

    Joined:
    Aug 22, 2006
    Location:
    Southeastern USA
    #8
    Because they become dust/debris magnets.
     
  9. tevion5, Jul 14, 2014
    Last edited: Aug 19, 2014

    tevion5 thread starter macrumors 68000

    tevion5

    Joined:
    Jul 12, 2011
    Location:
    Ireland
    #9
    Damn. It's not thick greasy stuff I put on. Very thin light "Silicone" general purpose lubricant is what I used.

    Might still clean it off though if you recommend it.
     
  10. tdiaz macrumors 6502

    Joined:
    Feb 7, 2006
    #10
    I use silicone spray as a cleaning agent on them explicitly for that reason, because it doesn't attract dust once wiped off.
     
  11. MacTech68 macrumors 68020

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #11
    To the OP - A silicone lubricant mostly wiped off would be fine, I agree. But copious amounts might eventually prove problematic as David says.

    The rails aren't lubricated by the OEM from new. However, wear on the plastic over the years might mean a small amount (using the apply and wipe off method) might be an advantage.
     
  12. tevion5 thread starter macrumors 68000

    tevion5

    Joined:
    Jul 12, 2011
    Location:
    Ireland
    #12
    Ahh that is good news. Well I didn't drench it by any means, just enough to wet the active section if the rails.

    All that's left now is to tinker around with the second drive.

    Thanks again for the help folks.
     
  13. MacTech68 macrumors 68020

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #13
    Regarding the second drive, make sure you are testing with the same "known good" Disk Controller Card in the Apple II. The 9334 on that card is also involved in the stepper motor.
     
  14. tdiaz macrumors 6502

    Joined:
    Feb 7, 2006
    #14
    That's pretty much it, by using the silicone as a cleaning/polishing agent, you're cleaning off any microscopic corrosion or tarnishing, for lack of a better term, and the same with the inside of the teflon sleeve for the head assembly to slide on the rail. Making it "like new" again.
     

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