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Add activity LED to MFM hard drive?

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    Add activity LED to MFM hard drive?

    In my PS/2, I've got a Kalok KL 320 MFM hard drive. I'll have to check the hard drive controller later for its model (Western Digital brand I think).
    So, I just wanted to add an activity LED to the hard drive so I could know when the hard drive was being used. Is it possible to do this?

    EDIT: The controller sticker says WDXT-GEN2-PLUS

    #2
    Yes, you can do it. Pin 1 on the data connector is "Drive Selected"--an output signal. You should be able to drive a small LED with it. Since this is a low-true signal, you'll want to take your LED drive between +5 and pin 1. Use a 470 ohm resistor in series with your LED to limit current.

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      #3
      Originally posted by linuxlove View Post
      In my PS/2, I've got a Kalok KL 320 MFM hard drive. I'll have to check the hard drive controller later for its model (Western Digital brand I think).
      So, I just wanted to add an activity LED to the hard drive so I could know when the hard drive was being used. Is it possible to do this?

      EDIT: The controller sticker says WDXT-GEN2-PLUS
      Even though I know it isn't the case here, the later microchannel PS/2s (usually with SCSI at that level) had no cable from the drive or controller to an activity LED, it was all done by the drive controller BIOS setting an I/O bit that the motherboard polled for display...
      Disclaimer: The username IBMMuseum and domain IBMMuseum.com are not affiliated with IBM in any manner

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        #4
        Originally posted by Chuck(G) View Post
        Yes, you can do it. Pin 1 on the data connector is "Drive Selected"--an output signal. You should be able to drive a small LED with it. Since this is a low-true signal, you'll want to take your LED drive between +5 and pin 1. Use a 470 ohm resistor in series with your LED to limit current.
        Most drives also have a 2-pin connector near the front for the LED in the (usually optional) bezel.

        Comment


          #5
          Originally posted by MikeS View Post
          Most drives also have a 2-pin connector near the front for the LED in the (usually optional) bezel.
          That's true for almost all 5.25" drives, but I don't see any reference to one on the Kalok 3.5", which was pretty much intended for "hard card use. That doesn't mean that there's not one there, however.

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            #6
            Well, I took the Kalok out of the PS/2 and there's no header for an LED. I did notice one thing though:



            The component with the arrow pointing to it has a solder pad that looks like a lot of electricity got pumped through it at one point. The drive still works though, so is this something to be afraid of?

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              #7
              Nothing from what I can see to be worried about, although you my want to solder that transistor tab down to match the others.

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                #8
                To make sure, the data cable on MFM hard drives is the skinny 20-pin one and not the 34-pin one?

                EDIT: And what band colors should I be looking for to find a 470 ohm resistor? I'm not quite sure how to use this: http://samengstrom.com/nxl/3660/4_ba...e_page.en.html
                Last edited by linuxlove; June 23, 2010, 10:21 AM.

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                  #9
                  Yes, data is the smaller cable and the wider cable is the control cable.

                  I'm afraid the link to the resister color codes is missing some info. It is more useful to look at a resister and determine is value than to determine the colors required for a particular resister value.

                  Black - 0
                  Brown - 1
                  Red - 2
                  Orange - 3
                  Yellow - 4
                  Green - 5
                  Blue - 6
                  Violet - 7
                  Grey - 8
                  White - 9

                  The number is substituted for the 1st 2 bands and the last band tells you how many zeros.

                  A 470 ohm resister would be Yellow (4), Violet (7), Brown (1 zero).

                  The last band is either gold or silver or none. Gold is 5% tolerance, silver 10%, none 20%.

                  The way I was taught to remember the resister color code was thru this mnemonic: Bad boys rape our young girls but violet gives willingly.

                  Comment


                    #10
                    Originally posted by Chuck(G) View Post
                    That's true for almost all 5.25" drives, but I don't see any reference to one on the Kalok 3.5", which was pretty much intended for "hard card use. That doesn't mean that there's not one there, however.
                    Well, I don't think any of my Kaloks survived so I can't check, but the ones I recall using (and selling, mea culpa) were just used in normal bays with 5 1/4 - 3.5 adapter brackets; AFAIR the 3.5" Miniscribes all had LED connectors, as did the Seagates, and could in fact be bought as a drop-in 5 1/4 replacement drive with brackets and a front bezel with an LED.

                    Apparently not the case with this Kalok however; no LED connector on the XT-GEN2 either? Surprising, most HDCs also had connectors for the front panel case LEDs.

                    Comment


                      #11
                      I got enough courage together and modified the controller:

                      The white wire is the negative line connected to pin 1 and under all that brown tape is the resistor.
                      The next step? Choose an LED color. At my disposal, I have red LEDs and green LEDs. I even have a blue one around somewhere :P

                      At first when I turned it on after the modification, I thought I burned up the card since the hard drive wasn't spinning. The actual cause? I forgot to plug in the power cable. Plugged it back in and tried again - it worked!
                      Thanks guys

                      EDIT:
                      Originally posted by strollin
                      The way I was taught to remember the resister color code was thru this mnemonic: Bad boys rape our young girls but violet gives willingly.
                      Uh... _

                      EDIT 2:
                      And of course, after I finish this, I find that the card does indeed have a header for activity LEDs...
                      Last edited by linuxlove; June 23, 2010, 12:05 PM.

                      Comment


                        #12
                        Originally posted by MikeS View Post
                        Apparently not the case with this Kalok however; no LED connector on the XT-GEN2 either? Surprising, most HDCs also had connectors for the front panel case LEDs.
                        As I understand the combination, they were offered as an ersatz (I love that word) Hardcard. No point to an activity connector on the drive or on the controller. The Kaloks, like anything associated with Jugi Tandon (remember the awful JTS drives?) cut corners everywhere.

                        Comment


                          #13
                          Originally posted by strollin View Post
                          Yes, data is the smaller cable and the wider cable is the control cable.

                          I'm afraid the link to the resister color codes is missing some info. It is more useful to look at a resister and determine is value than to determine the colors required for a particular resister value.

                          Black - 0
                          Brown - 1
                          Red - 2
                          Orange - 3
                          Yellow - 4
                          Green - 5
                          Blue - 6
                          Violet - 7
                          Grey - 8
                          White - 9

                          The number is substituted for the 1st 2 bands and the last band tells you how many zeros.

                          A 470 ohm resister would be Yellow (4), Violet (7), Brown (1 zero).

                          The last band is either gold or silver or none. Gold is 5% tolerance, silver 10%, none 20%.

                          The way I was taught to remember the resister color code was thru this mnemonic: Bad boys rape our young girls but violet gives willingly.
                          . . . . . Get (Gold) 5% - Some (Silver) 10% - Now (None) 20%
                          Surely not everyone was Kung-Fu fighting

                          Comment


                            #14
                            ...Right... let's move away from the discussion of rape?

                            In the attachment, here's what the system now looks like with the LED attached. Yay for Dremel tools.
                            The hole is small enough that it holds the LED in snugly so no need for glue or anything.
                            Attached Files

                            Comment


                              #15
                              Strange, I just spent a few hours cleaning up in my shed and ran across a kalok today.
                              The one I have here has a led right on the drive.

                              Bruce

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