Ever found a frayed DS10 internal SCSI cable? - VMS

This is a discussion on Ever found a frayed DS10 internal SCSI cable? - VMS ; I found a DS10 internal SCSI cable (17-04245-03) in bad shape. For an inch or two on both sides of the connector of the less exposed (middle) disk. Insulation gone, copper wires exposed. Insulation seemed to be melting or flaking ...

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Thread: Ever found a frayed DS10 internal SCSI cable?

  1. Ever found a frayed DS10 internal SCSI cable?

    I found a DS10 internal SCSI cable (17-04245-03) in bad shape. For an
    inch or two on both sides of the connector of the less exposed
    (middle) disk. Insulation gone, copper wires exposed. Insulation
    seemed to be melting or flaking away.

    One theory is that it was ozone. We have a one-pass air handler and
    our ozone levels are relatively high inside our building. But I have
    not seen this with other DS10s here.

    Or maybe some kind of vibration?

  2. Re: Ever found a frayed DS10 internal SCSI cable?

    On May 30, 12:37*pm, tadamsmar wrote:
    > I found a DS10 internal SCSI cable (17-04245-03) in bad shape. For an
    > inch or two on both sides of the connector of the less exposed
    > (middle) disk. *Insulation gone, copper wires exposed. Insulation
    > seemed to be melting or flaking away.
    >
    > One theory is that it was ozone. *We have a one-pass air handler and
    > our ozone levels are relatively high inside our building. *But I have
    > not seen this with other DS10s here.
    >
    > Or maybe some kind of vibration?


    BTW, the tape drive started working reliably in compaction mode again
    after I replaced this cable

  3. Re: Ever found a frayed DS10 internal SCSI cable?

    tadamsmar wrote:

    > One theory is that it was ozone. We have a one-pass air handler and
    > our ozone levels are relatively high inside our building.


    I doubt it is the ambient ozone level. If there was enough ozone
    floating around in the building to cause that much damage to wire
    insulation you'd probably all be in intensive care with severe lung
    damage, if it didn't outright kill you. The ozone level inside the unit
    could be higher if something in it was arcing. Even then, why would the
    damage be localized like that?

    Is it possible the cable was rubbing against something? A bit of
    resonance on the cable could result in enough motion over time to wear
    off the insulation if it could rub on en edge in the case.

    Rodents can cause that sort of wire damage, although I've never heard of
    a mouse getting into a small computer case like on the DS10.

    Regards,

    David Mathog

  4. Re: Ever found a frayed DS10 internal SCSI cable?

    Dear tadamsmar:

    On May 30, 9:37*am, tadamsmar wrote:
    ...
    > One theory is that it was ozone. *We have a one-pass
    > air handler and our ozone levels are relatively high
    > inside our building. *But I have not seen this with
    > other DS10s here.
    >
    > Or maybe some kind of vibration?


    Not likely ozone, unless the insulation was already damaged to
    unusability when the cable was fabricated. Heat or "solvents" wicking
    under the insulation would do this.

    SCSI drives that I have seen do get *very* hot, but not at the
    connector.

    Vibration would concentrate on the metal conductors as the stiffest
    part, and would not "overheat" the insulation. Likely vibration is
    what caused the functional failure of the drive... after the
    insulation failed and the conductors took all the vibration direct.

    I'd just check this cable again in a month and six months, to see if
    there is odd behavior there. If so, I would guess that it is the
    drive, and it may need a cooling fan directly on it.

    David A. Smith

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