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MPI 360k won't read/write

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    #46
    I recommend that you perform a diagnosis of your hard disk with Vivard, after that restore the boot order in your bios menu, let us know if it worked.

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      #47
      Originally posted by falter View Post
      So I took a chance and removed the head, bent the copper leaf spring just enough to get the top head to sit down properly.
      Well, now it may be a bit out of alignment. Without fancy test equipment, the first thing you should do is run ImageDisk, start "alignment mode", insert a known good factory-created write protected disk (such as a driver disk), and step through all of the tracks making sure all are readable, re-adjusting the head if needed.

      You can also use ImageDisk to check the RPM speed.

      Next you want to test writing over the entire disk. Probably the easiest way is format a known good disk and then verify with Norton Disk Test 4.5.

      If that looks like it is working, take the freshly formatted disk over to another system and again verify with Norton Disk Test 4.5 or similar.

      Once that is working, then you can test reading and writing individual files.

      With this kind of fix, if something is still a bit off, it is possible the the outer tracks are read/writing fine but the inner tracks may have problems.

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        #48
        It is also hoped that you measures the pots value before you adjusted it? The pot sets the write current.
        With the tracking being a little off, it would read a disk formatted by by itself. The azimuth could only be a tiny bit off so it is unlikely to be the problem. It is more likely that the head is still not coming down flat or is off relative to the other head.
        Dwight

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          #49
          Well, I'd suspect the trimmers (which are usually factory-set; that's why they often have a blob of glypt holding them in place.) if you couldn't format a floppy and write to it successfully. Otherwise, it's likely the alignment being off.

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            #50
            I knew the pot I was adjusting was out from the get go because I messed with it years ago. The other two are untouched.

            I noticed the head still had a slight tilt to the right so I rebent it. I also very slightly adjusted the alignment of the top head further to the right. I can now do some operations I couldn't before, like combining txt files into a single. The sound of the drive as it writes is sounding better. I'm not sure if I should keep moving the head slightly rightward or play with the one pot again. I gotta look at the guide and see what exactly I'm adjusting with that. Has a tiny little screw. Not a bigger plastic one like the other two.

            I'm pretty excited.. this is the most I've seen this drive do in.. forever.

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              #51
              Ok so I attempted to center the head just a bit more. Now, it will format, copy files, and run files copied on that disk. The other drive can read the directory but of course cannot open any of the files. So is this where I should stop messing with the head and look at that pot?

              Comment


                #52
                No, you need to look to the alignment, now. (Format, write, read) on the same drive means that the drive is operating more-or-less correctly. Not being able to swap disks between drives means that the alignment is messed up.

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                  #53
                  Ok.. so for noobsplaining purposes, when we speak of alignment are we speaking just of the physical head alignment? Are there likely to be any further PCB adjustments?

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                    #54
                    Nothing on the PCB. It's purely a relative positioning issue.

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                      #55
                      Thanks Chuck.

                      Am I safe to presume that the lower head, being untouched, is aligned ok?

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                        #56
                        I can't say that for certain. The head assembly is a complex system. The only way to have an inkling is to use something like IMD and check each head individually.

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                          #57
                          Ok. I'm running IMD test rpm and it says 272rpm on that drive.. does it need to be 300rpm right on?

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                            #58
                            Ah. So that pot I was messing with controls RPM. I dialed it in to about 299 rpm... which is what the other drive stabilizes at.

                            Comment


                              #59
                              With the disk out, carefully lower the head down by closing the door slowly. Most double heads have opposite flat sides such that only a narrow part overlaps ( the width of a track ). You don't want to close the door any more than just touching or you can chip them.
                              If both heads are completely rounded, they will be more difficult to get the tracking right. Often the heads are the same width looking at them straight on. you can get the right left close that way but in and out they are offset to just overlap.
                              Since you haven't messed with the other head, it is likely in the right place.
                              Good luck
                              Dwight

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                                #60
                                Forget what I just said, you drive has three pots.
                                Dwight
                                Last edited by Dwight Elvey; August 17, 2019, 10:57 AM.

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