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Thread: Macintosh Plus analogue board problem

  1. #1
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    Default Macintosh Plus analogue board problem

    Hi Folks,

    I have a non booting Macintosh Plus with an analogue board problem.

    With everything (other than flyback lead) disconnected, applying power results in the clicking sound in this video.
    Anyone recognise that sound ? I'd rather like to rule out the flyback transformer before starting to check & replace the caps in the power supply section.

    Worth noting that I suspect the problem is with the power supply section as, in addition to the clicking sound, the logic board does not power up and chime the speaker.

    Thanks

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    Well I seem to have fixed most of the problems with this board now.

    I have reflowed a number of dodgy looking solder joints on the yoke connector and the flyback transformer base and now the machine powers up with a reassuring 'bong' and boots from floppy.
    Next problem is that the floppy drive looks like it has had a hard life from someone. It is quite hard to get a disk in, and now it won't come back out again although its working in situ. The automatic eject mechanism does not seem to work.

  3. #3
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    Right. Have now completely disassembled the Sony floppy drive, cleaned and lubricated so its mechanically sound. New problem is that the plastic gears inside the eject motor mechanism have lost their teeth and so are not driving the sled to eject the disk.

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    So I repaired both a Mac Plus and a Mac 512k and had most of these problems. As noted, most of the Analogue board issues are with the solder joints, though I think I had one other problem... but obviously you got that sorted.

    For the floppies, you pretty much have to remove all the old grease thats on there, it basically turns into concrete paste. No idea what they used. I re-did it with white lithium grease. I didn't have the gear issue though I know others who have and they ordered new gears online.

    https://www.ebay.com/sch/i.html?_fro...+gear&_sacat=0

    They're a bit overpriced, I feel. If you had a resin printer, and new the info, I think this might help make a new gear:

    https://www.thingiverse.com/thing:16627
    Last edited by ngtwolf; March 19th, 2020 at 11:03 PM.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

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    Yes, thanks Brian,

    I followed the guide in this excellent video for stripping and cleaning the drive - YouTube

    I tried printing a gear but my low end Flashforge print resolution is just not good enough to print the gears. I have ordered some from a chap in Italy instead.

  6. #6
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    Quote Originally Posted by zippysticks View Post
    Yes, thanks Brian,

    I followed the guide in this excellent video for stripping and cleaning the drive - YouTube

    I tried printing a gear but my low end Flashforge print resolution is just not good enough to print the gears. I have ordered some from a chap in Italy instead.
    Yeah, I don't think FDM printers would do a good job at this. I have both an FDM (filament) printer and a SLA (resin) printer and I've thought about making gears to see how they come out, but I haven't needed one.

    Adrian (from the video you linked) is one of the folks I was referring to that ordered those gears as well. He does have an STL printer he hasn't set up yet, so none of us have tested it with that kind of printer. I have lots of spare parts around and luckily haven't had broken gears, so i haven't been inclined to look into it.. Plus I have no 400k mac disks anyway, and haven't got around to making any (need to rewire an adt pro cable for my 2gs). Too many projects that I have to prioritize 'needs' over 'interests'
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

  7. #7
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    Quote Originally Posted by ngtwolf View Post
    Yeah, I don't think FDM printers would do a good job at this.
    The problem is nozzle size. You can print medium to large gears on FDM printers fine, but if you want to print tiny gears, you need a much smaller nozzle. Most FDM printers come with 0.4mm nozzles, you'll need a 0.2 or 0.1mm nozzle to do small gears. The only problem with going to smaller nozzle sizes is they take much longer to print, but if you have a small part to begin with, it's not too much of a concern.

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    Quote Originally Posted by GiGaBiTe View Post
    The problem is nozzle size. You can print medium to large gears on FDM printers fine, but if you want to print tiny gears, you need a much smaller nozzle. Most FDM printers come with 0.4mm nozzles, you'll need a 0.2 or 0.1mm nozzle to do small gears. The only problem with going to smaller nozzle sizes is they take much longer to print, but if you have a small part to begin with, it's not too much of a concern.
    That's true, my fdm printer only has 0.4mm nozzels, i've never tried anything smaller (or larger). You'd probably need to do it with ABS filament, and that might pose a bit of issue as well depending on your printer. My FDM printer isn't the best, ABS is a challenge with it, so I probably wouldn't attempt (and since I have an SLA printer, no need to).
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

  9. #9
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    There's no reason to use ABS, PLA or PETG will work fine.

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