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Dell OptiPlex GXa won't boot; how to configure devices in SCSI BIOS

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    Dell OptiPlex GXa won't boot; how to configure devices in SCSI BIOS

    I recently got a Dell OptiPlex GXa, 233 MHz. Pentium II. It includes a hard drive. The hard drive is connected via SCSI. The internal CD drive is connected to the motherboard by a separate ribbon cable. The floppy drive is connected to the motherboard via another separate ribbon cable.

    The screen says that the SCSI BIOS is not installed and stops the boot process. The computer won't even boot from a floppy.

    I hit Ctrl-A at the right time to enter the SCSI BIOS. Here are a few screenshots. I'm very novice at SCSI. I know that SCSI requires assigning of device numbers and a physical terminator. I'm not quite sure how to tell it what device number is what. There is a physical terminator present. Assuming that the HDD is still good, how do I configure the SCSI BIOS correctly so the hard drive can boot from it? Or, even just boot from a floppy?

    IMG_7057 - Copy.PNGIMG_7029 - Copy.jpgMy observations so far on the blue tape. Showing SCSI terminator; the hard drive is the only SCSI device.
    IMG_7056 - Copy.PNGThe system BIOS. I changed drive A to 3.5-inch, 1.44 MB., but it still won't boot from it.

    IMG_7055 - Copy.PNGBoot up screen. If I don't press Ctrl-A in time, the boot process proceeds and the compujter says the SCSI BIOS is "not installed."
    IMG_7027 - Copy.jpgSCSI BIOS main menu. If I try the second option, the ASCII window clears and then no other ASCII window appears. I'm just stuck. This might be a problem itself.
    IMG_7028 - Copy.jpgSCSI configuration menu, following option 1 above.
    SCSI2.jpgSCSI boot device options.
    IMG_7031 - Copy.jpgSCSI device configuration.
    Attached Files
    Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
    "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
    "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

    #2
    From the screen shots:

    Error message 1: Dell BIOS is indicating, "Invalid configuration information - please run SETUP information".
    Error message 2: Dell BIOS is indicating, "Time-of-day not set - please run SETUP information".
    Error message 3: Adaptec AHA-2940U2W SCSI BIOS is indicating, "Host Adapter Configuration Error".

    I think they have separate causes.

    I suggest that you first remove the Adaptec SCSI card, and then address error messages 1 and 2.
    I expect that error message 1 is caused by: In the Dell BIOS SETUP, Primary Drive 0 is set to 'Auto'. Set it to 'None'.

    Then, when those errors are gone, add the AHA-2940U2W and continue.
    Note that per page 10 of the AHA-2940U2W User's reference, in the SETUP of the motherboard BIOS, leave the Drive 0 type set to 'None' (because you have no IDE drive, and the AHA-2940U2W's BIOS manages the SCSI drive).

    The Adaptec AHA-2940U2W is displaying, "Host Adapter Configuration Error". So, possibly like a corrupt CMOS SETUP configuration on a motherboard. I suggest that you try going into 'SCSISelect', making a minor configuration change of some sort (e.g. turn off parity checking), then saving the configuration. (You can always use the '<F6> - reset to Host Adapter Defaults' option in SCSISelect later on.)

    Originally posted by Bill-kun View Post
    Assuming that the HDD is still good, how do I configure the SCSI BIOS correctly so the hard drive can boot from it?
    The AHA-2940U2W's BIOS defaults to booting from the device set as SCSI ID 0. So ensure that the HDD is set to SCSI ID 0.

    (The AHA-2940U2W's BIOS may not attempt a boot whilst it is in a "Host Adapter Configuration Error" state.)

    Originally posted by Bill-kun View Post
    Or, even just boot from a floppy?
    That problem may go when error message 1 has been addressed.

    Comment


      #3
      Usually, the Adaptec 292x293x host adapters run fine "right out of the box". If you're booting from a SCSI drive, it should be SCSI ID 0 or 1. I can't think of the last time I had to play with the Adaptec configuration parameters--and I use Adaptec PCI controllers almost exclusively.
      Reach me: vcfblackhole _at_ protonmail dot com.

      Comment


        #4
        Those hardwired terminated SCSI cables are known to cause weird issues. If you have a 68 pin SCSI cable without a terminator stuck on it, try that cable instead and use host termination on the card itself. All of the AHA29x0 cards I have never play nice with those cables, the only place they're really needed is on Ultra 160 and 320 controllers that require them.

        Comment


          #5
          Sorry it took so long to get back to this. I was moving around other computers and vintage home inventory. I untangled a whole foot locker worth of computer mice completely tangled together, for example.

          Well, good news and bad news. The good news is I got closer to the actual root problem. The bad news is that I now have more repair to do on this computer than before.

          Originally posted by modem7 View Post
          From the screen shots:

          Error message 1: Dell BIOS is indicating, "Invalid configuration information - please run SETUP information".
          Error message 2: Dell BIOS is indicating, "Time-of-day not set - please run SETUP information".
          Error message 3: Adaptec AHA-2940U2W SCSI BIOS is indicating, "Host Adapter Configuration Error".

          I think they have separate causes.

          I suggest that you first remove the Adaptec SCSI card, and then address error messages 1 and 2.
          I expect that error message 1 is caused by: In the Dell BIOS SETUP, Primary Drive 0 is set to 'Auto'. Set it to 'None'.

          Then, when those errors are gone, add the AHA-2940U2W and continue.
          I disconnected the SCSI card. I set drive A to 1.44 MB. 3.5-inch floppy, which is correct. I set set the primary hard drive 0 to None. I put in a bootable MS-DOS 6.22 floppy. There were no longer any SCSI messages; but the computer said no boot device is available. It said "Drive seek failure on diskette drive 0." I unplugged the native floppy drive and tried 2 other known good floppy drives. The floppy drive lights never lit up at all. Made me think the power supply was probably faulty, supplying not enough power. After I thought of that, I noticed the power supply was noticeably quieter than I thought it should be. With the power supply turned on still, I measured the voltage on the 5-volt rail on the floppy drive Berg connector. It gave a reading of 0. I then tried on the 12-volt wire (admittedly backwards, with the red lead on the ground of the floppy drive Berg connector, but that should only give a negative sign, I think). It still read 0. After a few seconds of me hold it there, a small spark came from the leads and the power supply shut down. (It is possible the leads may have touched each other.) I cannot get it to power up again. The multimeter is unharmed; it never read any voltage.

          So the root problem seems to be something previously blown in the power supply, and now either blown more, or additional stuff is blown. Experience of my own and others points to capacitors being the first suspicion. Since I have more similar units, I may swap a power supply until I get around to fixing this blown one.

          Now I have to learn more about specifically power supplies. Power supply repair is the part of computer repair I hate the most because you can hurt yourself if you don't know what you're doing.
          Last edited by Bill-kun; November 30, 2021, 08:24 PM.
          Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
          "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
          "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

          Comment


            #6
            Originally posted by Bill-kun View Post
            I disconnected the SCSI card. I set drive A to 1.44 MB. 3.5-inch floppy, which is correct. I set set the primary hard drive 0 to None. I put in a bootable MS-DOS 6.22 floppy. There were no longer any SCSI messages; but the computer said no boot device is available. It said "Drive seek failure on diskette drive 0." I unplugged the native floppy drive and tried 2 other known good floppy drives. The floppy drive lights never lit up at all.
            * Bad data cable?
            * Bad power cable?
            * A computer like the PIII Compaq DeskPro, where the A: drive is before the twist, and B: after the twist ?

            Originally posted by Bill-kun View Post
            Made me think the power supply was probably faulty, supplying not enough power.
            With you seeing "Drive seek failure on diskette drive 0", the power supply must have been supplying +5V to the motherboard.
            And 1.44M diskette drives use +5V only (even though the cable also supplies +12V; which was used on early 720K drives).

            Originally posted by Bill-kun View Post
            After I thought of that, I noticed the power supply was noticeably quieter than I thought it should be. With the power supply turned on still, I measured the voltage on the 5-volt rail on the floppy drive Berg connector. It gave a reading of 0. I then tried on the 12-volt wire (admittedly backwards, with the red lead on the ground of the floppy drive Berg connector, but that should only give a negative sign, I think).
            Correct, the multimeter will see opposite polarity.

            Originally posted by Bill-kun View Post
            It still read 0. After a few seconds of me hold it there, a small spark came from the leads and the power supply shut down. (It is possible the leads may have touched each other.) I cannot get it to power up again.
            Blown fuse in the power supply?

            Originally posted by Bill-kun View Post
            So the root problem seems to be something previously blown in the power supply, ...
            I don't know. With you then seeing "Drive seek failure on diskette drive 0", the power supply at that time must have been producing +5V for the motherboard.
            * Bad measurement ?
            * Poor connection of diskette drive to power supply ?

            Comment


              #7
              * Bad data cable?
              Probably not, but not definite. If I swap the power supply, that will enable me to answer.

              * Bad power cable?
              Probably not, but not definite. If I swap the power supply, that will enable me to answer.

              * A computer like the PIII Compaq DeskPro, where the A: drive is before the twist, and B: after the twist ?
              The floppy drive data cable has 2 drive connectors on it. The twists (there are many) are between the drive connectors. The end drive connector is the one that gets connected to the 3.5-inch floppy drive. The end drive connector and floppy drive are both keyed via a missing pin/plugged pin hole. The other floppy drive connector is unused and not keyed.

              * Blown fuse in the power supply?
              Thanks for mentioning that, because I now realize that is far more likely than the total shutdown being caused by a bad capacitor(s). I carefully opened the power supply and looked around inside it. I am so far unable to notice a fuse inside the power supply. I also looked around on the motherboard but cannot find a fuse on that either. I set my eyes to look for both a cylinder-shaped fuse and an upright automotive-type fuse. The motherboard diagram unfortunately doesn't seem to be much help. I can see where the power supply connects to the motherboard, but so far cannot find a fuse.
              https://stason.org/TULARC/pc/motherb...IPLEX-GXA.html

              * Bad measurement ?
              I used the multimeter to measure a few other household voltages: wall outlet measured 121 VAC; 9-volt Duracell battery measured 9.4 VDC. So the multimeter seems fine.

              * Poor connection of diskette drive to power supply ?
              Probably not, but not definite. If I swap the power supply, that will enable me to answer.

              Other info I gathered:
              • The SCSI connection to the SCSI hard drive is 34-pin.
              • The SCSI card also has a 50-pin connector. There are 4 connectors on the data cable. The most proximal one is the CD drive. The 2 in the middle are empty. The one on the end goes to an unused external connector at one of the expansion car slots.
              • The floppy drive data cable connects directly to the motherboard.
              • The motherboard has 2 built-in IDE hard drive connectors. Both are empty. Probably a safe assumption that it had them, but I'm very happy to see it for sure since that gives me more options for the future. (Can I simultaneously have 4 IDE hard drives plus the SCSI hard drive(s)?)
              Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
              "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
              "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

              Comment


                #8
                After a few seconds of me hold it there, a small spark came from the leads and the power supply shut down. (It is possible the leads may have touched each other.) I cannot get it to power up again.
                I'm not commenting on causing a short while doing a simple voltage measurement, as stuff like that seems to happen whatever you try to do...

                But the thing is, a PSU that no longer works after a short between a voltage rail and ground is certainly bad. There are protection circuits inside that should just power-off the PSU without any side-effect. It should power on again when the short is removed. If it does not, replace it. Please don't try to repair the PSU. No offence meant, but if you don't even have a steady hand to messure a voltage without causing a short, the insides of a PSU are nothing you should even think about messing with. The stored voltage inside can kill you even hours after it was last connected to mains.

                Comment


                  #9
                  Originally posted by Bill-kun View Post
                  The floppy drive data cable has 2 drive connectors on it. The twists (there are many) are between the drive connectors.
                  Are you sure they are 'twists' (i.e. electrical twists - wires/pins are getting rerouted)? I ask because, based on one of the Dell Optiplex GXa photos at [here], the floppy cable appears to simply have slices in it longitudinally (presumably to make the cable more flexible).

                  Originally posted by modem7 View Post
                  * Bad measurement ?
                  Originally posted by Bill-kun View Post
                  I used the multimeter to measure a few other household voltages: wall outlet measured 121 VAC; 9-volt Duracell battery measured 9.4 VDC. So the multimeter seems fine.
                  Although, "bad measurement" includes things like:
                  * Probe not actually getting far enough into connector to reach pin.
                  * Probe not piercing oxide layer.
                  * Probe not piercing coating (if one exists).

                  Comment


                    #10
                    Are you sure they are 'twists' (i.e. electrical twists - wires/pins are getting rerouted)? I ask because, based on one of the Dell Optiplex GXa photos at [here], the floppy cable appears to simply have slices in it longitudinally (presumably to make the cable more flexible).
                    Upon my closer inspection, you are right. There is only one actual twist. The longitudinal cuts are apparently just to make the cable more flexible. A bit ironic, considering how many ribbon cables there are in this case.

                    But the thing is, a PSU that no longer works after a short between a voltage rail and ground is certainly bad. There are protection circuits inside that should just power-off the PSU without any side-effect. It should power on again when the short is removed. If it does not, replace it. Please don't try to repair the PSU. No offence meant, but if you don't even have a steady hand to messure a voltage without causing a short, the insides of a PSU are nothing you should even think about messing with. The stored voltage inside can kill you even hours after it was last connected to mains.
                    Amen. The more I thought about it, the more I disliked the idea of myself messing with the power supply to do anything besides replace a clearly found fuse. I tried turning it on again, though, and it did turn on. Same computer behavior as before.

                    Although, "bad measurement" includes things like:
                    * Probe not actually getting far enough into connector to reach pin.
                    * Probe not piercing oxide layer.
                    * Probe not piercing coating (if one exists).
                    I measured a couple of the Molex power connectors. Red is +10.3 VAC (should be +5 VAC). Yellow is +25.1 VAC (should be +12 VAC). Measured using 2 different multimeters. In lieu of measuring on the Berg floppy connector again, I instead verified continuity (power off and power supply discharged) of all 4 wires between a Molex connector and the Berg connector. They verified. (It's hard to get even a needle-shaped lead to make contact on a Berg connector.)

                    It appears something in the power supply is making it give approximately double the prescribed voltage. I will do no more work on this power supply myself. I will mark the power supply as "Dangerous" and mark it with the readings I took and date, and eventually if I decide I want to use it I will have a qualified TV repairman fix it first. Meanwhile, I will get at my other first generation OptiPlexes and scavenge a power supply. Then back to the issue at hand of making this GXa computer boot.
                    Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
                    "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
                    "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

                    Comment


                      #11
                      Originally posted by Bill-kun View Post
                      Red is +10.3 VAC (should be +5 VAC). Yellow is +25.1 VAC (should be +12 VAC).
                      I'm sure you meant "VDC".

                      Originally posted by Bill-kun View Post
                      It appears something in the power supply is making it give approximately double the prescribed voltage.
                      And that is with the power supply connected to the motherboard (i.e. power supply 'under load') ?

                      Comment


                        #12
                        Originally posted by modem7 View Post
                        I'm sure you meant "VDC".
                        No, I meant VAC. I measured again in VDC.
                        Red is +5.10 VDC.
                        Yellow is +11.87 VDC.
                        So both those are good. This is why I'm a mechanical engineer, not an electrical engineer.

                        Originally posted by modem7 View Post
                        And that is with the power supply connected to the motherboard (i.e. power supply 'under load') ?
                        Affirmative.

                        So, if the power supply is good (which is good), then that leads me back to why won't any floppy drive respond? I suppose I can swap the floppy data cable next, although I don't see why it would be bad.
                        Last edited by Bill-kun; December 1, 2021, 08:45 PM.
                        Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
                        "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
                        "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

                        Comment


                          #13
                          Originally posted by Bill-kun View Post
                          So, if the power supply is good (which is good), then that leads me back to why won't any floppy drive respond? I suppose I can swap the floppy data cable next, although I don't see why it would be bad.
                          Comparing the Dell Optiplex GXa photos at [here] to your photos in post #1, the cable connection at the floppy drive is different.
                          On the other Dell Optiplex GXa, it looks as though the floppy drive might be on the middle connector. Hard to tell.

                          Comment


                            #14
                            Originally posted by modem7 View Post
                            Comparing the Dell Optiplex GXa photos at [here] to your photos in post #1, the cable connection at the floppy drive is different.
                            On the other Dell Optiplex GXa, it looks as though the floppy drive might be on the middle connector. Hard to tell.
                            No, my GXa and the other GXa both have the floppy drive plugged in using the end connector on the floppy data cable.

                            I found out the problem: The floppy controller was simply turned off on page 2 of the system BIOS. I didn't even know you could do that! It is off by default. Once I enabled it and told it to try booting from the floppy first, the floppy drive came to life as expected. Boy, oh boy. Also, I need to get this girl a new CR2032 BIOS battery so I don't have to remember to change all these settings back on every single boot.

                            Step 1 accomplished: I got the computer to boot from by floppy. Next is to put the SCSI card back in and figure out how to do configure the SCSI hard drive properly, as device 0.

                            I have also tried out some IDE hard drives on the IDE channels. Those work fine. It is really nice to have a computer that can autodetect just about any IDE hard drive I connect to it.
                            Sattinger's Law: “It works better if you plug it in.” Corollary: “It works even better if you plug it in correctly.”
                            "The simplest solution is the most likely solution." --My paraphrase of Occam's Razor
                            "You can get [a computer] like yours at a garage sale for, like, fifteen dollars," --Strong Sad, sbemail #33

                            Comment


                              #15
                              Originally posted by Bill-kun View Post
                              Next is to put the SCSI card back in and figure out how to do configure the SCSI hard drive properly, as device 0.
                              Per my post #2, I think you will first need to get rid of the "Host Adapter Configuration Error" that the SCSI card is showing.

                              Comment

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