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Recent content by alexGS

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    Color Classic II Mystic Upgrade with Rev D analog board issues

    Amazing - thanks for providing the link. Hard to believe the monitor/analog board was capable of handling an increased resolution/increased frequency all along! Back at that time, it would really have helped, as some newer software assumed a 640x480 display. I guess that Apple had strict rules...
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    Macintosh 128k/512k/Plus SW1 powerswitch drop-in replacement

    This is a really good idea - well done! :) Many of the original switches seem to have corroded contacts from battery leakage. I hadn’t found that switch size.
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    Macintosh 128k/512k/Plus battery socket drop-in replacement

    I’m in NZ and I’ve been working on something similar, I use 3D-printing to solve lots of problems like this. I made a battery for the Powerbook 100 that uses CAT5-wires (the stripped wires from the cable) to thread through holes in springy parts of the design. So, you can join the dots on what I...
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    Macintosh Classic won't start

    Cheesestraws is absolutely right - I do the wash in hot soapy water (with dishwashing liquid) first, scrubbing with a toothbrush, and then after blow-drying, I use IPA to rinse. I haven’t had any problems with speakers or flybacks - I’m just careful not to touch the speaker when it’s wet. When...
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    Macintosh portable backlit m5126 floppy issue

    Yes - replacing the SWIM chip restored the correct operation of the floppy drive in the backlit Portable that I was working on :)
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    Wide vertical bars on a Mac Plus - help, please

    I replaced the 6522 twice more, using chips taken from old 512K boards that don’t work for other reasons. I’ve installed a 40-pin socket so the 6522 is easy to swap. Both of the older 6522s produce a new result - the startup tone sounds (yay!), and then the screen is blank (boo!). Floppy drive...
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    Macintosh Classic won't start

    Yep, and then replace the optocoupler again. Voltages will probably be back to normal - for a while. Cleaning the analog board in hot soapy water does seem like a good idea, if you’ve had that much gunk floating around that a diode leg was corroded off.
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    Macintosh Classic won't start

    Good stuff. One thing to think about - when you replace the optocoupler - I think they are possible to damage with soldering temperature, and I think that’s why they are socketed in the original Mac/Mac Plus analog board. So, the last optocoupler I fitted to a Classic, I took a row of pin...
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    Macintosh Classic won't start

    So you heard a bang, but you’ve still got some voltage produced? Check the two 0.1uF capacitors that are wired across the AC input - they are near the metal frame. They often split/explode. If anything else has gone bang, it seems impossible that it would turn on at all. To fix the low voltage...
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    SE/30 Sound and Boot Freeze Issues

    It feels like if there was one cracked via (corroded via from capacitor leakage perhaps), then there’s probably another, this time from the SWIM? I really appreciate your thorough report of the sound and boot problems and their cause, I feel I may be facing something similar one day.
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    Wide vertical bars on a Mac Plus - help, please

    I’ve now replaced the 6522 - which has changed the display to that below (please disregard the 512K Mac case/analog board used for testing - this is a Plus logic board producing this display) It’s now bars alternated with slightly-shorter bars below - I don’t know what it means, does anyone...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Luckily no-one commented on the filthy condition of the Mac 512K that I was working on - it’s finished now :) I treated the case with water+peroxide+sunlight, but then I also gave it a light spray-painting of a carefully-matched beige colour, so with a bit of luck, it should stay this way...
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    "Retrobrighting" Powerbook keys?

    It’s been a while but I think it’s the edge closest to the display that pops free first. I recall they are robust (the white plastic stabiliser is not brittle). Use something like a blunt knife to pry the edge of the keycap upwards.
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Best of luck! I eventually reached a situation that I was happy with. Several further learnings; 1 - I recommend arranging a longer cable, for example an external drive cable, to avoid the EMI interference problem (from the Mac’s screen) while making adjustments with the drive’s top cover...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    I’ve learned a few things today, but the most stark was the truth in the above. I learned that if I click Format Disk in the test program, it should immediately start formatting - if it returns to track 0 and throws an error, then starts formatting on a second click of Format Disk, that means...
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