Connecting ATA Master/slave drives with ribbon cable

Question

Connecting ATA Master/slave drives with ribbon cable

Okay, now I know some folks can shed some light on this question.

I have two ATA drives connected as master/slave and everything works fine. I tried using a new ribbon cable that came with a Maxtor internal 120GB drive to replace the one I have which is the original.

The current connections with the original are as follows:

Black connector on master.
Gray connector on slave.
Blue connector on the logic board.

The new cable has the same color connectors so all I did was swap them out. When I turned on the G4, all I got was a gray screen. So the new ribbon didn't work for whatever reason.

So I put the original ribbon cable back in and everything was fine.

Tried a second time with the new cable, still a no go. I did make sure that the new ribbon was fully connected at each port.

I did notice that the original cable has a blank spot right in the middle of the connector on all three connectors. The new one does not have that blank spot. Could the new cable be for PC ATA setups? If so then I guess I need a Mac compatible ATA ribbon cable? That dosen't seem right but as you can probably see, I'm now a h/w smart person.

Any comments thinking as to why the new ribbon dosen't work and what would wortk?

Thanks,

Bob

PM G5, 1.8, SP 1.5GB ram, 160 & 300GB HD; 1GB G4, 2GB ram Apple SD 300GB HD, Mac OS X (10.3.9), 500GB Ext HD, PB G4, 1.25, FW800, 1.5GB ram.

Posted on Jan 13, 2006 3:22 PM

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Answer 1

Jan 13, 2006 4:26 PM in response to Bob O'Halloran

Hi Bob

I believe the blank spot on the connector is to prevent the cable from being inserted upside down. The drives should be missing a pin in the corresponding location, so the cable is correctly keyed.

If your new cable doesn't have the blank spot, I guess it's possible to insert it with the side that should be facing upwards, downwards. I'm not sure whether it would work if you happened to insert both ends of the cable upside down, but it sounds as if you may have one inserted the right way and one the wrong way.

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Answer 2

Jan 13, 2006 5:02 PM in response to Rodney Culling

Hi Rodney,

Thanks for the response. I think I understand what you are saying. Here is a bit more detail.

I connected the blue end into the logic board so that the other two connectors (gray/black) have the pin side facing toward the drives with rhe gray connector in the middle for slave, black on the end for master.

If I turn the blue end around and make the connection, then the black end is on top and the gray on the bottom. In order to keep the black connector on the bottom so it connects to the master I would have to twist the ribbon to do that.

I don't know if that makes sense, seems kind of difficult to explain.

Is what I'm saying clear?

Thanks,

Bob

Boy , for something that seems so easy, it can get confusing.

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Answer 3

Jan 13, 2006 9:52 PM in response to Bob O'Halloran

Hi, Bob -

Apple KBase Article #24958 - B&W G3 & G4 - hole in IDE/ATA cable describes that gap (hole) in the IDE ribbon cable. From the description it appears to be an intended modification, and so using an unmodified cable may not work.

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Answer 4

Jeff

Level 6

12,328 points

Jan 13, 2006 10:43 PM in response to Bob O'Halloran

With the top of the hard drive facing up, the "up" side of the ribbon cable's connector will have a raised "key" in the middle and/or two small grooves closer to the ends. The key on the connector aligns with a notch in the slot. When connecting ribbon cables having the pink/red tracer conductor along the edge of the cable, the cable is correctly connected, when that colored-conductor is beside the power connection. As for twisting the cable to connect two adjacent drives, it's sometimes necessary to remove the drives from the carrier and swap their positions, relative to each other. That way, the designated master and slave connectors can be plugged into their respective drives without issue.

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Answer 5

Jeff

Level 6

12,328 points

Jan 13, 2006 11:13 PM in response to Don Archibald

When Bob wrote, "I did notice that the original cable has a blank spot right in the middle of the connector on all three connectors.," I believe that he was referring to the missing "hole" found on ribbon cables with connectors having only 39 holes instead of 40. As Rodney pointed out, this safeguard prevents the cable from being plugged in upside down, because the drive's center pin along the bottom row would have no matching opening on the connector into which it could fit.

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Answer 6

Jan 14, 2006 2:18 AM in response to Jeff

Hi,

Thanks to all for responding. The information was very informing and answered my questions and I now have the proper connections.

Yes, my original ribbon does have 39 holes in it while the new ribbon has 40.

The placement of the raised notches and noting the pink/red line placement did the trick.

I will say though that I did need to turn the ribbon so that the middle (gray) connector's notch was facing up so I could connect to thje slave properly.

Thanks again,

Bob

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Answer 7

Jan 14, 2006 2:42 AM in response to Bob O'Halloran

Hi Bob,

As Jeff mentioned, the cable should have some sort of key, if not a blank spot then a raised notch in the middle of one side of the connector or a red line on one side of the ribbon cable.

Failing that, with the original cable inserted and the drives working, I guess you could pick a pin on the logic board connector, say top right, and follow it's path down the ribbon cable to see which pin on each drive it's connected to. With the new cable laid out beside the computer and imaginarily plugged into the logic board connector, you could do the same and see if the same pin on the logic board would be connected to the same pins on each drive.

Failing that I guess you could continue using the original cable which seems to work!

Edit - as I was typing this it seems you've now got the problem sorted.

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