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Thread: jackhammer termination woes

  1. #1
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    Hi folks- I recently added an external jaz drive to my "regular" scsi chain which includes a zip 100 drive. I had to remove an old Syquest drive to do this. I also have a Studio Array with a Jackhammer card. Now all of a sudden my scsi 2 chain (as reported by scsi probe) is NOT terminated. I did go out and buy a new terminator which didn't help. I can't figure this out. The Studio Array icon appears on the desktop and works per usual (although I haven't tried to do high speed capture). Any opinions would be a help!! Thanks!

  2. #2
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    Sounds like that's exactly what the problem is

    So.. question though - where in the chain (physically) is the new Jaz located?. Was it in the same place as the Syquest?. Is it at the end of the chain? If so, then that drive must be explicitly terminated. Double check to see that if you are using an external terminator, that then internal termination on the drive is off. Sometimes the internal circuitry gets screwy.

    BTW - I'm assuming that the Studio Array is on a physically separate SCSI bus.

    Bad cabling and bad terminators are a bear to diagnose.. Try removing or altering the sequence of devices in the chain - ensure that the last device on the bus is is terminated.

    Chris

  3. #3
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    Hi Doc- Thanks for your speedy response. I remember now some other details I left out of my first posting. I was trying to pin point just which device and/or scsi bus was causing the termination problem. I disconnected the Studio Array from the Jackhammer card (and yes, it does occupy a seperate scsi bus). After removing this drive the termination problem no longer appeared. To double check my results I disconnected both the zip and jaz drives from their scsi bus and reconnected the Studio Array to it's bus. Wa-La, the termination problem rears it's ugly head again. This makes me think the problem lies within the scsi 2 bus somewhere. As I said before, I bought a new terminator for the Studio Array, which didn't help at all. I can't figure it out. I didn't even touch the scsi 2 bus when adding the jaz drive yet the problem is apparently coming from there. I hope this additional information helps.
    Thanks-
    Karen

  4. #4
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    Hi

    I'm a bit confused (it's late)...

    What machine are you working on?.

    If the problem disappeared when you removed the Studio array from the Jackhammer card (and that was the only device on that card), then that would suggest that the Studio Array was to blame (or its termination was).

    The fact that you removed the Zip and Jaz from their bus but reconnected the Studio Array and the problem returned has likely nothing to do with those devices and the bus they are on but would suggest something with the Jackhammer card.

    Is this your set up

    bus # 1: SCSI -> Zip / Jaz

    bus #2 : Jackhammer -> Studio Array

    How is the Jaz / Zip SCSI chain terminated? - what is the last device on the bus? and I'm assuming everything has proper SCSI ID numbers...

    Chris

  5. #5
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    damsel. Are you using the JackHammer Control Panel? Have you set the card Termination to Auto? I'm thinking that it's possible that the external port of the JackHammer is set to on and it's seeing double termination when the array is connected. This would be just as much a problem as no termination at all!

  6. #6
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    Hello again folks-
    Here's some additional information. I'm running an 8100/110 machine with nubus cards.
    Lasvegas, Iam using the Jackhammer control panel but there isn't (as far as I can tell) any type of termination options for the nubus version.
    Doc, my configuration is as you illustrated.
    bus # 1: SCSI -> Zip / Jaz
    bus #2 : Jackhammer -> Studio Array
    The Zip/Jaz chain is terminated using the termination switch on the back of the Jaz drive (the Jaz being the last drive on the chain).
    SCSI ID's are as follows:
    Zip=5
    Jaz=6
    Studio Array= 1/2

    I really appreciate all your help you guys.
    Karen

  7. #7
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    Karen,

    We were all thinking later (PCI slots) Macs. You're right, the NuBus JackHammer does not have termination settings in its Control Panel.

    What it has is three resistor packs mounted on the JackHammer card just to the left of the internal 68-pin connector and below the internal 50-pin connector. Just like the PCI JackHammer Control Panel settings, these resistor packs set termination at the card end of the bus. You still have to terminate the last device at the far end of the SCSI chain.

    In order to determine how many of these resistor packs must remain installed and which ones (assuming you do not have a NuBus JackHammer manual), I need to know what is connected to the internal and external connectors and whether all three resistor packs are installed at Term 16, Term8 1, and Term8 2. The packs are long and thin, I've forgotten the color but I think light green or some other light color.

    Internal 50-pin connector - anything installed?
    Internal 68-pin connector - anything installed?
    External 68-pin connector - Studio Array?

    In SCSI Probe, what does it say is the manufacturer and full model number of the Studio Array drives? Need to know this so that we can search for jumper pin settings and locations to enable termination on the last array drive on the chain (the far end) and be sure the other array drive is not terminated.

    That info should get us started. k

  8. #8
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    Hi all-
    First I'd like to apologize for leading you on a "PCI" wild goose chase. I'm really sorry about that.

    Kaye-
    I've pulled the card out of my mac. There were three light blue resistor packs at the terms you asked about.

    Here's what SCSI probe 5.2 reported:

    SCSI BUSES:
    2-FWB Incorporated NCR53C720

    SCSI DEVICES
    ID TYPE VENDOR PRODUCT VERS
    1 disk seagate ST12550W 0006
    2 disk seagate ST12550W 0006

    7 cpu apple PowerMac 8100/1.. 9.0

    Also, there are no devices connected to either internal connector. And, yes, the Studio Array is connected to the 68-pin external connector.

    I hope this info is helpful.

    Thanks-
    Karen

  9. #9
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    Karen,

    I'm very glad those resistor packs are there because they would be very hard to find. With just your external JackHammer 68-pin connector being used, all three resistor packs remain in place on the board. That satisfies the need to teminate that SCSI chain at the card end of the chain.

    NCR53C720 refers to the SCSI controller chip on the JackHammer.

    I'll go search around for the ST12550W jumper pin settings, specifically the Termination Enable (TE) jumper pins, not to be confused with the Termination Power (TP) jumper pins. The JackHammer supplies TP and it is not good to have more than one device supplying TP such as one or both ST12550W's and the JackHammer. k

  10. #10
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    Go to http://www.seagate.com/cgi-bin/view....i/st12550w.txt

    This page is very cluttered but you are interested in the J4 jumper pins. Looking at the end of the drive where the 68-pin connector is located and oriented so that the J4 jumper pins are to the right of the 68-pin connector, you are interested in the J4-6 two pins (horizontal) Enable Drive Terminators. Note that those two pins could be the next to the bottom pins or the bottom pins (some drives don't have J4-7 pins). So count from the top, don't just assume that J4-6 pins are next to the bottom.

    Now the drive physically closest on the SCSI cable to the JackHammer should not have these pins jumpered (a little plastic jumper that slides over the J4-6 pins horizontally, sometimes black, sometimes gray). The drive furthest away, the last drive on the chain, should have J4-6 pins jumpered horizontally.

    Remove the terminator you purchased. It may be a passive terminator. It must be an active terminator to work, or maybe it just doesn't work correctly.

    While you are looking at both drives, take notes of all pins that are jumpered on J5, J4, and J01. Crank up and see if things are working correctly. Be sure to ask if you are not sure about anything before proceeding very far. k

  11. #11
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    Hi guys-
    Kaye, I've opened the Studio Array and I'm gonna try to give you an ASCII "picture" of what I've found.


    -------------------------------{oo}
    -------------------------------{oo}
    this area has no pins---
    -------------------------------|oo|
    -------------------------------|oo|
    -------------------------------|oo|
    -------------------------------|oo|
    -------------------------------|oo|
    -------------------------------|oo|
    -------------------------------|oo| <---- are these the J4-6 pins?


    This indicates jumpered pins {oo}
    This indicates non-jumpered pins |oo|

    The reason I post this is because I couldn't quite tell from the Seagate page which pins I should start counting down from to locate tha J4-6 pins. I guess I just wanted your opinion as to which set of pins you think is J4-6.

    Hope this makes sense to you-
    Karen

  12. #12
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    J01 block of pins:
    -------------------------------{oo}
    -------------------------------{oo}
    this area has no pins---

    J4 block of pins:
    -------------------------------|oo|<---J4-1
    -------------------------------|oo|<---J4-2
    -------------------------------|oo|<---J4-3
    -------------------------------|oo|<---J4-4
    -------------------------------|oo|<---J4-5
    -------------------------------{oo}<---J4-6 horizontally placed ***
    -------------------------------|oo|<---J4-7

    This indicates jumpered pins {oo}
    This indicates non-jumpered pins |oo|

    *** Only on the last drive on the chain.

    Something puzzles me about J01 block. It looks like you are saying there are two jumpers there. Let me redraw it:

    J01 block of pins:
    {oo}
    ?| |
    {oo}

    where "|" is the jumper placed vertically (not horizonatally). That config means Term Power to SCSI Bus and Drive. We want Term Power from SCSI Bus. So it should be like this:

    J01 block of pins:
    {o-o}<--jumpered
    |o?o|<--not jumpered

    Only one jumper, on the top pins and horizontally. Hope this makes sense. Very common for these pins to be misconfigured. JackHammer supplies Term Power to the SCSI Bus. Two sources of Term Power is not good. If both drives are configured your way there are three sources of Term Power.

    Only if the total length from the jackHammer connector thru the external cable thru the internal array cable to the last drive terminated, if that distance exceeds 3 meters, then you might need the jumper config for Term Power from Drive, but only on the last drive. Questions? k

  13. #13
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    Hi Kaye-
    I just wanted to ask you one more question. Which drive do I jumper the top set of J01 pins?

  14. #14
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    You want both drives set for Term Power from SCSI Bus. So you jumper the top set of J01 pins on both drives. k

  15. #15
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    Hi folks-
    Kaye, I still had the same termination problems with the Studio Array after making the changes you suggested. I have no experience or knowledge to back this up but, I keep getting this feeling it's something with the jackhammer card. I was able to pick up a new (I assume used) card from ebay this Sunday so I'll know in a week or so if this is the case. Either way, I'm still very open to further sugestions.

    Thanks for all your help-
    Karen

  16. #16
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    Karen,

    Try one more thing with that JackHammer card. Move it to another NuBus slot and see. If no better, we wait a week. k

  17. #17
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    Kaye, I may be misreading this, but I think your diagram sets the drive up for Term Power From Drive.

    If this is the block of pins:

    J01 block of pins:
    -------------------------------{oo}
    -------------------------------{oo}
    this area has no pins---

    Let's number them this way for clarity:

    J01 block of pins:
    -------------------------------{1 2}
    -------------------------------{3 4}
    this area has no pins---

    I believe that you recommended a jumper across pins 1 and 2. That diagram in the Seagate docs is hard to read, but I compared it with a booklet I have for the 32550 and it appears that the following is indicated:

    1) Jumper pin 1 to pin 2 for Term. Pow. from Drive
    2) Jumper pin 2 to pin 4 for Term. Pow. from SCSI bus.
    3) Jumper pin 1 to pin 3 for Term. Pow. to SCSI bus.
    4) Jumper pin 1 to pin 3 and pin 2 to pin 4 for Term. Pow. to both SCSI bus and drive from Drive.

    So I believe she would want a single vertical jumper on the outer two pins of the J01 block to achieve Termination Power from SCSI Bus. As I said, that Seagate diagram is difficult to read but I think the
    +-+ is meant to indicate a rectangle surrounding a pair of pins
    +-+ representing a jumper.

    Karen, also make sure, as Kaye indicated, that J4-6 is jumpered on the last drive on the chain. You want to count the pins from the top and don't just go to the second to last set of pins, because the Seagate docs indicate that the last set of pins is absent on some models.

    [This message has been edited by trag (edited 14 May 2002).]

  18. #18
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    trag,

    You're correct. I agonized over that diagram but found another this morning http://www.seagate.com/support/disc/scsi/st12550w.html that clearly shows a J01 jumper on pin 2 to pin 4 for Term. Pow. from SCSI bus. Even this diagram I had to think about because it shows the drive with the the jumper blocks J4 and J01 vertical but just below the jumper blocks are horizontal. Ouch!

    Glad you helped out here. Karen, my error. Very sorry. Try it and let us know. You want that particular jumper on both drives. k

  19. #19
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    Hi all-
    You're all being such a great help to me. I will try the new "configuration" when I get home from work tonite. Thanks....you're my buds!!

    Karen

  20. #20
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    Hi folks-
    I changed the jumpers as suggested by trag. Unfortunately my termination problem still exisits. Oh, kaye, I forgot to mention that I also switched nubus slots as you suggested.

    This is one stubborn beast.

    Karen

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