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Gsbtom

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  1. Gsbtom

    Mac Plus screen issue

    Remember the Plus logic board layout is different. Also, I’m guessing at this stage what the issue could be.
  2. Gsbtom

    Mac Plus screen issue

    There’s a brightness cutoff pot on the board as well, though that seems unlikely. Mac Repair Secrets does have some schematics, see https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upgrade_Secrets_1990.pdf also, check Q3 and see if there’s any discoloring on the heat sink. Edit: On page 104 of Mac Repair Secrets, it suggests maybe the LAG on the logic board might be bad.
  3. Gsbtom

    Mac Plus screen issue

    Silly question, but does the brightness knob do anything? Maybe the brightness cutoff is set to max?
  4. Gsbtom

    Who knows HyperDrive boards?

    http://vintagemacmuseum.com/collection/rare-items/ Looks like there was a version for the 128, which cost more, since it upgraded the 128 to a 512.
  5. Gsbtom

    Mac Plus screen issue

    DMS (from your post on that other thread) is Pina’s Dead Mac Scrolls book. A quick google should find it in PDF form (not sure if allowed to post link here). Looks like your problem might be described on page 54. Replacements available, see link in this post (the whole thread is probably worth a read):
  6. Might be the picture, but a lot of the traces on that analog board don’t look good, like there’s a lot of corrosion. Judging by the patch wire, looks like repairs have been attempted before.
  7. Gsbtom

    Need boot disk for Mac Plus

    I literally just tackled this problem this weekend in my Plus. In my case, the gears were fine, just like yours. The solution was to pop the gears off and lube the gear posts. To see if this is your issue, pop the gears off and try an eject and see if the eject motor spins up (you’ll hear it easily if it does). Last picture in this post shows the gears I popped off to expose the motor:
  8. Gsbtom

    Is my flyback transformer dead?

    Finally got some free time yesterday to continue working on this. Replaced the battery, cleaned out the little bit of corrosion on the positive terminal. Installed the 4 MB of RAM. Sweet, now I can run Civilization! Squirted some WD-40 into the troublesome left shift key and let it sit overnight, as of this morning, seems to be working flawlessly. For now anyway, looks like the keyboard issue is solved. Next, the troublesome floppy drive. I was surprised at how relatively clean and dust free it was. Guess leaving it in the Apple bag for 30+ years was a good idea. Pulled it apart, cleaned both of the heads. Figuring the eject gears might be a problem, I pulled it apart to inspect. Gears are all intact, so I pulled the top plate off, Again, remarkably clean. Cleaned and greased up everything here. That's much better, everything's sliding nicely now. I opted against pulling the heads out. The head rails looked clean, so I carefully just q-tipped in some more grease on the rails. If I muck up the track zero sensor, I'm basically SOL as I literally only have one working DD floppy. However, still no luck with the eject. In fact, it didn't even appear that the eject motor was even engaging on eject. I could see the heads move to the right spot, but the motor never appeared to engage. For grins, I figured I'd check the connector solder joints. These look ok, except for maybe the bottom one, but I couldn't tell if that was the light or if the solder joint was bad, but I figured it couldn't hurt to touch them up. Quickly realized after this that I need some smaller solder tips. Way smaller. And much better vision than I have. I cleaned up the mess I made out of this. I was kind of out of options here. As a last ditch, I pulled the eject motor again, and pulled all the gears off to see if at least the motor was turning. Surprise, surprise, once the gears are off the motor actually engaged. So, cleaned and greased up the gear posts, and voila, I've got a working eject mechanism! One question: I did watch a couple of YouTube videos on this (super helpful on seeing what pieces did what), and all I watched suggest that I should be aligning the eject pin to 12 o'clock (that's left on the above pic), mine's aligned to 11:30 it looks like. I was adjusting this when I was trying to get the motor going, but ended up putting it back to where it was during my diagnosis. Any reason I can't just leave it? Or is it better to truly line that up? I'm not sure here, as the 800k disk I have does seemingly reliably eject (it's been so long that I don't remember how a brand new drive ejects).
  9. Gsbtom

    Is my flyback transformer dead?

    Neato.. thanks! Learned something new today!
  10. Gsbtom

    Macintosh Plus won't boot from rare HDD

    I picked up one on eBay from blairdus, reasonably priced. It isn’t apple branded, but listed as supporting the Plus, and it does in my case.
  11. Gsbtom

    Is my flyback transformer dead?

    Oh interesting, didn’t realize you could tell visually like that.
  12. Gsbtom

    Macintosh Plus won't boot from rare HDD

    To be fair, I pulled this suggestion from Dead Mac Scrolls, but it might make sense here. The drive is likely formatted for the IIgs, and the Plus can't read it, and therefore chokes on it.
  13. Gsbtom

    Macintosh Plus won't boot from rare HDD

    What about booting from floppy, and then turning on the drive? Assuming it boots, the Mac won't see it, but you might be able to reformat it. Dead McAfee Scrolls suggests this, and using Silverlining 5 to reformat it... Edited to add: Remember the Plus doesn't provide termination power, so if your drive doesn't provide it, you'll need to add it in the SCSI chain. You can find pass through SCSI terminators easily enough on eBay. If I recall, you pug the DB25 into the Plus, the 50 pin into the passthrough, and the passthrough to the drive. Also, if the drive has a selectable SCSI id, try 5 or 6 (I think the Plus reserves 0 for itself).
  14. Gsbtom

    Macintosh Plus won't boot from rare HDD

    Remember SCSI does require termination. My guess would be your cable goes into "IN", and a terminator would need to be plugged into "OUT". Some drives had internal termination (my ProAPP20S does, for example). It's also possible that given the Plus's wonky implementation of SCSI, you might want to try an Apple spec cable (these can be found on eBay).
  15. Gsbtom

    Is my flyback transformer dead?

    Looks like it's an 800k drive, judging by the size of the one floppy I have (779k formatted according to Finder). And it's ejecting now, albeit it seems like it's straining a bit, so looks like I might be able to clean it up and get it fully working without much effort. So looks like the eject motor's ok. Might be an issue with the gears, but won't know until I inspect it more closely. Given that the 512 would only have had a 400k by default, I'm wondering if I got the 800k drive during the Plus upgrade... On the keyboard, yeah, I definitely got this after the fact. When I originally got the Mac, I got a nice case for it, which had space for the computer, the original keyboard, mouse and external floppy. The Plus keyboard sticks out the top (so you can't quite zipper it closed) as the case wasn't made for it obviously, heh. I do remember the external numerical keyboards, pretty sure the Mac's in the school's computer lab had them, though pretty sure I never did. I may have had an external floppy, though that's probably long lost. Other fun stuff: I found a folder labelled CS231 folder on the hard drive, with Turbo Pascal and Lightspeed Pascal, and a bunch of Pascal school projects still there. It's been 30+ years since I've written any Pascal code, though (all C#/Java these days), so it's kind of neat looking at 19 year old me attempting to code.
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