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Thread: Seeking hard drive interface pinout for PS/2 8530 "30-286"

  1. #1

    Default Seeking hard drive interface pinout for PS/2 8530 "30-286"

    Hey there

    I'm looking for the pinout for the hard drive interface on the motherboard of an IBM PS/2 30-286 (certain varieties of 8530, but not all, because 8530 is also the 8086 model, which might or might not have the same HDD interface...I'm not sure).

    As I understand it, it is a 100% standard "ST506" or "ST412" type interface, just with both control and data pins plus the power connector all integrated in one single connector. There are probably enough pins on it for this to be possible, especially if common grounds were combined into a smaller number of pins.

    More or less I'm looking for the power wires because I want to use a nonoriginal hard drive and will therefore need a molex connector...but the PSU has none and I'd prefer not to start chopping up wires. If I can simply stick a berg connector on some specific pins in the hard drive interface, it's a lot cleaner.

    Thanks
    Last edited by kishy; August 30th, 2009 at 03:23 PM.

  2. #2
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    Hmm, I thought that this was an ESDI drive. :/
    Anyways, if you are looking to do this because you are missing the original hard drive I got a pile of drives from both a 30 and 55SX that should work and I can throw in a front bezel and the drive rail if you need them.
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  3. #3

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    Quote Originally Posted by NeXT View Post
    Hmm, I thought that this was an ESDI drive. :/
    Anyways, if you are looking to do this because you are missing the original hard drive I got a pile of drives from both a 30 and 55SX that should work and I can throw in a front bezel and the drive rail if you need them.
    I never found any info confirming it was ESDI definitely, but some people have told me in the past it may be. I know I found somewhere a reference to it being ST506 based, and if it isn't, then it would be 100% proprietary...very little info about ESDI seems to exist online so I can't get a clear answer myself.

    I have the 20mb out of a Model 70 but it uses a different but similar connector.

    Shipping from BC to ON is brutal; Canada Post are ridiculous. Switching to PM to discuss possibly getting one off ya.

    Anyone know the pinout, motherboard-side?

  4. #4

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    Quote Originally Posted by kishy View Post
    Hey there

    I'm looking for the pinout for the hard drive interface on the motherboard of an IBM PS/2 30-286 (certain varieties of 8530, but not all, because 8530 is also the 8086 model, which might or might not have the same HDD interface...I'm not sure).

    As I understand it, it is a 100% standard "ST506" or "ST412" type interface, just with both control and data pins plus the power connector all integrated in one single connector. There are probably enough pins on it for this to be possible, especially if common grounds were combined into a smaller number of pins.

    More or less I'm looking for the power wires because I want to use a nonoriginal hard drive and will therefore need a molex connector...but the PSU has none and I'd prefer not to start chopping up wires. If I can simply stick a berg connector on some specific pins in the hard drive interface, it's a lot cleaner...
    http://www.ibmmuseum.com/ohlandl/mis...tml#IBM_XT_IDE

    The (MFM) interface is particular to the Model 25 (8086 and 286 versions, not the 25SX 386SX version) and Model 30 (8086 and 286 versions). Drives from the Model 50-021 (non-´Z´) and ¨DBA ESDI¨ models (50Z, 55SX, 70, P70) are different. Only 20 and 30Mb sizes were made for the interface (the 8086 version of the Model 30 was only able to use the 20Mb size), and it would be a drive parameter table lookup to run the drive.

    An easier upgrade is to put in an expansion card and 3-1/2¨ drive (like some 8086-based Model 25´s had stock with a Seagate MFM adapter)...

  5. #5

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    Quote Originally Posted by IBMMuseum View Post
    http://www.ibmmuseum.com/ohlandl/mis...tml#IBM_XT_IDE

    The (MFM) interface is particular to the Model 25 (8086 and 286 versions, not the 25SX 386SX version) and Model 30 (8086 and 286 versions). Drives from the Model 50-021 (non-´Z´) and ¨DBA ESDI¨ models (50Z, 55SX, 70, P70) are different. Only 20 and 30Mb sizes were made for the interface (the 8086 version of the Model 30 was only able to use the 20Mb size), and it would be a drive parameter table lookup to run the drive.

    An easier upgrade is to put in an expansion card and 3-1/2¨ drive (like some 8086-based Model 25´s had stock with a Seagate MFM adapter)...
    Hmm...thank you.

    One thing however,
    "IBM Unique XT-Bus (PS/2 Model 25 and 30) IDE Connector "
    The majority of the time someone says MFM, they're referring to an ST412-type interface.

    IDE (referring to the broad category, not specific XT-IDE type) doesn't include those types because the drive controller is built into the drive, whereas the interfaces most people normally would label as MFM or RLL don't have an integrated controller on the drive.

    So, not considering connectors at all, is that basically XT-IDE? Finding info on XT-IDE is also hopeless, even books that address the topic say something to the effect of "it's so unpopular we won't talk about it" (ahem, Mueller).

    Is the pinout motherboard-side or drive-side? Without a cable I can't figure the missing one out based on the known one (machine came to me lacking an IBM drive and cable; this specific unit never had an original HDD, the one it had which is now dead was user-added).

    Your mention of the 70 in there tells me the drive (20mb, large single connector, for a model 70 something) I have now is ESDI, correct?



    --
    The idea behind finding the pinout is actually to do what you said, separate controller card and normal drive. The problem is the lack of molex connectors for power, so I want to draw the power out of the motherboard hard drive connector, but need to know where those power pins are. I could do what Peter Wendt suggests on his site and add them to the power supply, but I'd prefer to keep this easy-to-undo.

    The majority of controller cards seem not to supply power leads, though my Adaptec "ST412" RLL card does, but without a working drive to use on it that's kind of irrelevant.

  6. #6

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    Quote Originally Posted by kishy View Post
    ...One thing however, "IBM Unique XT-Bus (PS/2 Model 25 and 30) IDE Connector "... ...So, not considering connectors at all, is that basically XT-IDE?...
    No, just how Louis Ohland is choosing to label them...

    Quote Originally Posted by kishy View Post
    ...Is the pinout motherboard-side or drive-side?...
    Planar-side as far as I knew...

    Quote Originally Posted by kishy View Post
    ...Your mention of the 70 in there tells me the drive (20mb, large single connector, for a model 70 something) I have now is ESDI, correct?...
    No, what is called ¨DBA ESDI¨ (Direct Bus Attachment)...

    Quote Originally Posted by kishy View Post
    ...The idea behind finding the pinout is actually to do what you said, separate controller card and normal drive. The problem is the lack of molex connectors for power, so I want to draw the power out of the motherboard hard drive connector, but need to know where those power pins are. I could do what Peter Wendt suggests on his site and add them to the power supply, but I'd prefer to keep this easy-to-undo...
    You may still want to put mating connectors attached to the power supply. A 44-pin IDC connector is hard to find in supply channels. At least the Model 30 286 PSU (shared with the Model 55SX and Model 53) has a higher wattage than the Model 30 8086.

    I had even seen that Mode 30 8086 90-watt PSU adapted by a manufacturer to run in a clone case with a 486DX PGA CPU motherboard (probably with a goodly current draw)...

  7. #7

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    Quote Originally Posted by IBMMuseum View Post
    Planar-side
    Thank you, will investigate further

    Quote Originally Posted by IBMMuseum View Post
    No, what is called ¨DBA ESDI¨ (Direct Bus Attachment)...
    Hmm...well, fortunately it doesn't have much of an impact on me, since I don't have a machine that has it. I find search engines never find appropriate info on terms like these so the pages with this info are not being indexed, it seems.

    Quote Originally Posted by IBMMuseum View Post
    You may still want to put mating connectors attached to the power supply. A 44-pin IDC connector is hard to find in supply channels. At least the Model 30 286 PSU (shared with the Model 55SX and Model 53) has a higher wattage than the Model 30 8086.
    44-pin IDC connector would not be used; I would be using berg connector(s) for the pins in the motherboard's HDD interface connector, and attached to the berg connector(s) would be a molex power lead. Basically, it would be the same thing as taking it from the PSU directly, only doing it neater and cleaner (and 100% undoable). I'd be using an ATA hard drive on a controller card.

    Quote Originally Posted by IBMMuseum View Post
    I had even seen that Mode 30 8086 90-watt PSU adapted by a manufacturer to run in a clone case with a 486DX PGA CPU motherboard (probably with a goodly current draw)...
    Wow...why would they even do that, it seems to me it would be a nightmare if the PSU were to fail. Cool nonetheless.

  8. #8

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    Alright, attached is a photo of what I'm hoping to do.

    Yellow: +12V
    Black (x2): Ground
    Red: +5V

    Using a 5-pin Berg connector, spanning pins 32-40 even only.

    According to the pinout (http://www.ibmmuseum.com/ohlandl/mis...l#IBM_XT_IDE):
    32 +5Vdc
    34 Ground
    36 Ground
    38 Ground
    40 +12Vdc

    ...with pin 38 remaining unused, in my situation.

    The ends of those wires would be attached to a Molex lead I cut off an old junk power supply (I knew I'd need one eventually for something).

    *In theory*, will this work?
    If it'll work in theory, I don't see why it shouldn't in practice.

    Concerns: power draw
    Using a significantly more modern drive than this interface was intended for, so I don't think it should be an issue, but worth mentioning anyway.

    Another thing: are all of the +12V pins supposed to be combined together, or will only one suffice? Same for +5V? Same for ground? Nearly half the pins in the connector are ground.

    Edit: answered this kind of on my own with my multimeter and a visual circuit trace inspection
    Both 5vs are directly connected to each other
    All 12vs are directly connected to each other
    All grounds ground together
    This suggests to me that they used multiple pins to prevent burning up thin wires in ribbon cables, and that I should probably gang these pins together in my setup as well.

    (there are 3x +12v, 2x +5v...since the drive should in theory not need separate "rails" I don't see why there would be multiple pins unless there's a risk of burning up the wires)

    Thoughts?


    http://img17.imageshack.us/img17/302...86hddpower.jpg
    Last edited by kishy; October 4th, 2009 at 06:08 PM.

  9. #9

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    Quote Originally Posted by kishy View Post
    ...Another thing: are all of the +12V pins supposed to be combined together, or will only one suffice? Same for +5V? Same for ground? Nearly half the pins in the connector are ground...
    You answered yourself, but if the lines are tied together at the connector, tie them together at the other end of the cable. Even PS/2s that were not microchannel (everything below 50 in model numbers) had half of the connection pins as ground. On the microchannel bus that is standard.

    Hard drive expansion cards designed for the Model 30 typically have a power connection for the drive. Seagate (in a five pin header), SCSI cards, s-IDE (mounts for a molex connector), etc. You might be able to take advantage of that supplied connection.
    Last edited by IBMMuseum; August 31st, 2009 at 08:42 PM.

  10. #10

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    Quote Originally Posted by IBMMuseum View Post
    You answered yourself, but if the lines are tied together at the connector, tie them together at the other end of the cable. Even PS/2s that were not microchannel (everything below 50 in model numbers) had half of the connection pins as ground. On the microchannel bus that is standard.

    Hard drive expansion cards designed for the Model 30 typically have a power connection for the drive. Seagate (in a five pin header), SCSI cards, s-IDE (mounts for a molex connector), etc. You might be able to take advantage of that supplied connection.
    Thanks for the clarification (connecting together), I figured originally maybe they were separate +12V supplies so combining them together could potentially create +24V (for example) but since they're interconnected on the PCB it makes no difference.

    The RLL card I was using previously had a power supply lead for the drive, but of course my drive is dead so the card is not useful. I could probably just leave it in there to use as power supply but I figured there could be conflicts with whatever other card I end up using (right now looks like a JPN CA8390 IDE/FDC card, but the PS/2s internal floppy gets disabled when it is installed, so that's a bugger).

    None of the cards I have except that RLL card have a power supply header unfortunately.

    If anyone's interested I'll post back with any progress, and if nobody's interested, I will anyway.

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