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About Turaiel

  • Birthday 03/19/1993

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    Ann Arbor, MI

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  1. Hello again, It's been a while since I updated this thread. I've decided to pick up this project again but I'm still stuck in the same place I was in September. That is, the machine bombs if I try to shut down, restart, or press the interrupt button. No floppy port is functioning either, including external. It's possible that back when I was testing voltages out of the floppy connector, I touched the data and power leads together with my probe. Is my SWIM perhaps damaged, and more importantly, is this recoverable? Also, any ideas on the wrong voltages appearing on the board?
  2. More update: with some assistance I've identified that the voltages across capacitors C8 and C9 are inverted. The PSU is outputting healthy voltages as far as I can tell (though the -12V line is running at about -10V). Any ideas?
  3. As an update, neither floppy drive on my SE/30 is functioning now, including the external. The external now will not even power on. On top of that, I now get a "bus error" when I try to shut down the machine. The restart button on the dialog just causes it to do the same thing, and the interrupt button on the programmer's key just cases an "unserviceable interrupt" error. These symptoms were not present prior to my voltage testing. I hope I didn't fry anything...
  4. The voltages are definitely reading negative, unless for some reason the red probe is supposed to go on the ground pins. Pin 9 is measuring around -7.5V. Something of note: pin 11, which was reading -7ish V yesterday is now 0V (on both machines). The machine which was previously working can no longer read disks. The SE/30 also powered off unexpectedly while I was testing and refused to turn back on until I removed the power from the PSU for a few seconds.
  5. I just got a chance to check the voltages here. On both my SE/30 (issues) and SE (known good), pins 13, 15, 17, and 19 are measuring around -12V with pin 11 measuring between -7 and -7.6. You mentioned they should be +12 and +5, so the reversed polarity seems a bit weird to me.
  6. I'll check the link, thanks. I've tried both ribbon cables. They work in the SE, but not the SE/30 (the one with the issues).
  7. I resoldered the floppy header, but it seem to no avail. It still is unable to recognize disks. I did try to format an 800k disk I had lying around, and it said it was unable to initialize it. As for the above pinout, I'm afraid I'm not sure which diagram you're referring to.
  8. I don't remember what happens if I try to format it. I'll check this week once I get the machine reassembled. Right now I've got it torn apart to check those traces and joints.
  9. When I insert a disk in the internal drive, regardless of the type of drive and type of disk, the OS tells me the disk is unreadable and prompts me to format it. The disk and one of the drives is known to be good and works fine in my other Mac SE.
  10. I found that the things pointed out were most likely a combination of bad lighting and dust/cotton swab fibers. I've cleaned up the areas a bit, so here are some new pictures. I still can't find anything particularly worrisome.
  11. I did the capacitor replacements myself. Can traces be shorted if they aren't exposed on the surface? I'll have to check them more closely when I get back on Monday. Thanks!
  12. Thanks for pointing that out. I looked over the top and bottom of the board around this chip and I didn't find any obviously bad traces, but my electronics skill is minimal. I've attached some photos in case anyone can see anything that sticks out to them.
  13. I guess that wouldn't surprise me terribly. The board wasn't in great shape when I started the repairs; corrosion everywhere. Which chip is that so I can inspect it?
  14. It only fails to recognize disks in drives connected to the internal floppy header. The same 800k drive works externally. The original internal drive is a 1.44 MB drive, which just doesn't seem to work in general. However, if I plug THAT drive in externally, the head moves a little bit but the drive doesn't work at all. To summarize: 1.44 MB drive doesn't recognize disks internally or externally. Externally it spins slightly but doesn't react otherwise. 800k drive works perfectly externally, does not work internally. I am using 800k disks in both, and HD disks only in the 1.44 MB drive.
  15. From what I've read, the Bourns filter going bad generally causes an unresponsive gray screen on boot. In this case, the system does boot fully and if the system disk is removed, it will attempt to read from the internal and external floppy drives. The problem is just that it thinks that all disks on a drive connected to the internal port are uninitialized.
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