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Thread: 1571 drive mechanics, anyone?

  1. #1

    Default 1571 drive mechanics, anyone?

    Hi all,
    I have a 1571 disk drive with bad heads, head 1 has open erase coil, head 0 has an open R/W coil. Otherwise electronics and the rest of the mechanical assembly looks good.
    First question: can a bad electronic component damage the head's coils? I've checked the electronics connecting to the heads (dioes, transistors) but almost all the head's electronic R/W is in the hybrid IC on this drive.

    Second question: does anyone have a 1571 mechanics even destroyed but with good R/W heads assembly?

    Thanks
    Frank IZ8DWF

  2. #2
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    Quote Originally Posted by iz8dwf View Post
    Hi all,
    I have a 1571 disk drive with bad heads, head 1 has open erase coil, head 0 has an open R/W coil. Otherwise electronics and the rest of the mechanical assembly looks good.
    First question: can a bad electronic component damage the head's coils? I've checked the electronics connecting to the heads (dioes, transistors) but almost all the head's electronic R/W is in the hybrid IC on this drive.

    Second question: does anyone have a 1571 mechanics even destroyed but with good R/W heads assembly?

    Thanks
    Frank IZ8DWF
    This is apparently a very common problem on the 1571. I had to replace the heads on my 128D's drive a while back as one side the head was bad on. A gentleman on here from Switzerland (IIRC?) sold me a set of NOS heads for the Newtronics mechanism. He may still be around?

  3. #3

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    Thank you Geoff!
    So these heads fail with no external abuse? That seems strange, but that's also a Commodore product, so anything is possible
    On a second 1571 I'm repairing now, I've found the first bad 6502 in my repair history (I keep almost all MOS/CSG bad chips that I substituted since the '80s), the head coils appear to be all good anyway.

    Frank

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    Quote Originally Posted by iz8dwf View Post
    Thank you Geoff!
    So these heads fail with no external abuse? That seems strange, but that's also a Commodore product, so anything is possible
    On a second 1571 I'm repairing now, I've found the first bad 6502 in my repair history (I keep almost all MOS/CSG bad chips that I substituted since the '80s), the head coils appear to be all good anyway.

    Frank
    That's my understanding. I couldn't tell you where I heard that though. There are additional issues with the head tensioning strap/hinge for the top head getting bent by the head lifter when left open for a long time, and also with the fine wires to the top head fatiguing and breaking at the solder joints. On mine I was able to swap the top and bottom head wires on the connector to the board and format the top as track 0 with a single sided format, so it was definitely the bottom head that was dead.

  5. #5

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    Quote Originally Posted by geoffm3 View Post
    That's my understanding. I couldn't tell you where I heard that though. There are additional issues with the head tensioning strap/hinge for the top head getting bent by the head lifter when left open for a long time, and also with the fine wires to the top head fatiguing and breaking at the solder joints. On mine I was able to swap the top and bottom head wires on the connector to the board and format the top as track 0 with a single sided format, so it was definitely the bottom head that was dead.
    Yes, I repaired one 128D's drive that needed the top head mount to be gently and lightly rotated to make proper contact. On this one, I've checked head coils directly on the head's contacts, so bypassing the wires, so I can exclude a wire problem. The fact that head coils get open without any electronic failure seems just poor manufacturing process or an extra cheap process.
    I have several older drives with similar heads (Apple disk-II, various CBM, 360k-PC) and repaired a lot more of them. This is the second time I found interrupted head coils, and the first time it was on a 1541.
    I've contacted the person who sold the 1571's replacement heads, so fingers crossed
    Frank

  6. #6
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    The only time I've seen it happen (so far) was on a couple of Disk ][ drives. One which I had just about since it was new, and one that I got on eBay.

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