Questions about Quantum Prodrive LPS

Discussion in 'PowerPC Macs' started by poiihy, Jan 8, 2015.

  1. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #1
    Soon after I first installed OS X on my beige G3, the Quantum ProDrive LPS stopped working (stopped showing up in the system). Just randomly started. It is 80 megabytes and empty so I didn't really care and I didn't have time to fiddle with it. This was before I transported it here. It's been not working ever since. Why doesn't it work?
    Note: The beige G3 is bricked (bad PSU and can't get anywhere) and I have no other computer with SCSI so I cannot test SCSI drives anymore.

    Second question:
    What are these three things that plug in right behind the SCSI port? See the image attached.


    P.S. These old hard drives have such fat logic boards that almost 1/3rd of the device is just the board! When you take the board out, you can see that the actual disk drive is quite thin!
     

    Attached Files:

  2. catzilla macrumors 6502

    catzilla

    Joined:
    Dec 15, 2013
    Location:
    Rhode Island
    #2
    Those are SIP (single inline pin) resistors, probably for termination.
     
  3. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #3
    what happens if they are not there?
     
  4. catzilla macrumors 6502

    catzilla

    Joined:
    Dec 15, 2013
    Location:
    Rhode Island
    #4
    It depends on where it is in the SCSI chain, IIRC, it's been awhile since I played with SCSI. Try both ways, you won't hurt anything.
     
  5. bunnspecial macrumors 603

    bunnspecial

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    May 3, 2014
    Location:
    Kentucky
    #5
  6. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #6
    Oh I see.

    the beige G3 only has 2 SCSI slots so both drives would have the termination enabled.

    Maybe this ProDrive stopped working because a resistor pack went loose. When I looked at the drive, the middle pack was bent. Could these packs loose contact and cause the drive to stop appearing?

    I don't know if I should open the drive or sell it because I don't know if it can be fixed. It has good treasures inside I would like to get at :eek:
     
  7. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #7
    The beige G3 that I'm familiar(I have two of them, and have spent a fair bit of time with both) with has an internal SCSI port to connect to a 50 pin ribbon cable and an external DB-25 SCSI connector. I'm pretty sure both ports are on the same bus.

    If you are only using internal SCSI devices, the bus needs to be terminated at the controller and at the last device on the internal chain. I've seen SCSI ribbon cables with anywhere from 2 to 7 connectors on them, but the ONLY device that should be terminated on the ribbon cable is the last hard drive-which you would normally plug into the end of the ribbon cable. Terminating any other devices can cause problems.

    By the way, I'm pretty sure the G3 logic board(and most other OWR Mac logic boards) are automatically terminating, meaning that the SCSI controller will turn termination off if devices are connected to both the internal and external SCSI connectors. I have a handful of Adaptec PCI SCSI cards with both internal and external connectors, and they all work this way also. The last device in the external SCSI chain must be terminated also-some external devices have a switch on the back to turn termination on or off, while others on others you have to plug a separate terminator into the back of the device.
     
  8. poiihy thread starter macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #8
    What about the sudden disappearance? It just randomly stopped working out of the blue (it does not show up in the system, not even in disk utility). Could it be because one of those terminator resistors got loose? Or could it be the hard drive has completely died?
     
  9. bunnspecial, Jan 12, 2015
    Last edited: Jan 12, 2015

    bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #9
    Could be either. You can't rule out spontaneous death with components this old. Try it again with the resistors seated.

    Also, since you indicate that you have multiple drives in this system, make sure you don't have any ID conflicts and make sure no other device is terminated. Normally the last device would be ID 0 and the second hard drive ID 1, although I don't think these specifics actually matter as long as no two devices have the same ID.

    If you have some means of power the drive outside the computer(I have a power brick with a molex plug on the end that is really handy for this kind of stuff), plug the drive in and listen to it spin up. Older drives do normally "grind and crunch" a lot, but something like a stuck/crashed head or dead motor should be pretty obvious.
     

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