Okay I figured I'd mail this off for interest sake... Many of you may have noticed that IDE hard drives are missing one of the 40 pins in the connector and opposite the missing pin there is a notch in the frame around the pins... both of those features are supposed to act as wards against someone plugging the cable in backwards.
To work with the wards mentioned above some IDE cables have a red strip, a extra bit of plastic plugging one of the pin holes, AND a chunk of plastic attached to the outside of the frame (which goes in the notch mentioned above). I say some because some cables don't have any of those, most have a pick-and-match sort of set of features. Some of you may have found that if you plug a cable with no wards in backwards the system tends to not POST... (power it on and nothing appears to happen, often the drives don't even spin up). Well maybe one or two of you have wondered what would happen if you take a cable with the little bit of plastic plugging the pin hole (but no chunk of plastic on the outside) flip it around, so it is backwards, then shove it hard enough into a hard drive that it seats. If you are luckiest you will just bend the hard drive pin that is in the way. If you are un-luckiest the pin will break off. In some cases the pin will push into the frame of pins and break contact with the drive controller card. Well the surprise is that if you go into the BIOS and disable DMA mode the drive is mostly functional... You will see that pin 21 is the DMA Request pin... that tells the drive a DMA mode request is coming, without it no DMA transfers work but you can use one of the slower PIO modes. http://www.cablingdirectory.com/pinouts/internal/ATA40PinCablePinout.htm The pin-out list from this page is correct, the diagram is not... from what I understand IDE pins are numbered one above the next, not length wise. So it is like: 1 3 5 2 4 6 not like: 1 2 3 21 22 23 If you decide that you want to repair this, you'll notice that the hard drive controller card attached to the pin frame, the card tends to be attached to the hard drive body via some torc screws (something smaller than size T-10, but if you push real hard a T-10 (which can be found at most hardware stores) will spin the screw). After taking the card off the drive, pushing the pin back into place, bending the cross metal piece back into place, and use of a soldering iron with a fine tip... the drive can resume DMA mode. Wondering why hardware gets on my nerves sometimes, Mike ps: If you attempt the repair, just be sure to cover the card body with a piece of newspaper so if you touch the iron to the board you don't melt it. pps: This is why I like cables without the little bit of plastic blocking a pin, but with a big chunk of plastic on the outside. _______________________________________________ vox-tech mailing list [EMAIL PROTECTED] http://lists.lugod.org/mailman/listinfo/vox-tech
