Apple Lisa Troubleshooting: Difference between revisions

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[[File:Apple Lisa (photo).jpg|thumb|right|300px|Apple Lisa. Source: Wikimedia Commons.]]
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* '''IDEfile''' — ProFile emulator using IDE drives
* '''IDEfile''' — ProFile emulator using IDE drives
* Both provide higher reliability than original Widget drives
* Both provide higher reliability than original Widget drives
== ⚠️ The I/O-board battery pack — remove it now ==
The Lisa keeps its real-time clock alive with a '''4 × AA NiCd pack strapped to the bottom-right of the I/O board'''. These packs leak corrosive electrolyte and are the single most destructive Lisa fault &mdash; when they let go they can '''destroy the I/O board and the motherboard, and in rare cases the CPU and RAM boards'''. '''Remove the battery pack from any Lisa immediately''', and clean and repair any corrosion before powering up.<ref name="lisa">[https://lisafaq.sunder.net/single.html The Apple Lisa FAQ]; [https://tinkerdifferent.com/threads/lisa-2-repair-journey.1151/ Lisa 2 repair journey], TinkerDifferent; [https://www.classic-computers.org.nz/blog/2011-03-05-rejuvenating-a-lisa2-10.htm Rejuvenating an Apple Lisa 2/10], Tezza's Classic Computers; and the Apple Lisa Do-It-Yourself Guide. Source for the I/O-board battery-pack leakage, the PSU failure, the Twiggy-drive unreliability, and the boot-ROM error codes (40 = CPU/MMU, 57 = disk controller).</ref>
== Boot self-test and error codes ==
The Lisa boot ROM runs a self-test and, on a fault, shows a '''numeric error code''' and draws a '''cross (X) over the icon of the failing board'''. Useful codes:
* '''40''' — CPU-board / MMU fault (a failed MMU register test loops endlessly; the CRT goes blank once warm).
* '''57''' — disk-controller fault.
The card-based design makes diagnosis a matter of swapping the '''CPU, memory and I/O boards'''; almost everything is user-replaceable except the CRT and video board.<ref name="lisa">[https://lisafaq.sunder.net/single.html The Apple Lisa FAQ]; [https://tinkerdifferent.com/threads/lisa-2-repair-journey.1151/ Lisa 2 repair journey], TinkerDifferent; [https://www.classic-computers.org.nz/blog/2011-03-05-rejuvenating-a-lisa2-10.htm Rejuvenating an Apple Lisa 2/10], Tezza's Classic Computers; and the Apple Lisa Do-It-Yourself Guide. Source for the I/O-board battery-pack leakage, the PSU failure, the Twiggy-drive unreliability, and the boot-ROM error codes (40 = CPU/MMU, 57 = disk controller).</ref>
== Power supply ==
A Lisa that '''runs for a few minutes and then switches off''', or will not power on at all, has a failing power supply — a known weak point that should be serviced/recapped.<ref name="lisa">[https://lisafaq.sunder.net/single.html The Apple Lisa FAQ]; [https://tinkerdifferent.com/threads/lisa-2-repair-journey.1151/ Lisa 2 repair journey], TinkerDifferent; [https://www.classic-computers.org.nz/blog/2011-03-05-rejuvenating-a-lisa2-10.htm Rejuvenating an Apple Lisa 2/10], Tezza's Classic Computers; and the Apple Lisa Do-It-Yourself Guide. Source for the I/O-board battery-pack leakage, the PSU failure, the Twiggy-drive unreliability, and the boot-ROM error codes (40 = CPU/MMU, 57 = disk controller).</ref>
== Twiggy drives (Lisa 1) ==
The Lisa 1 used two Apple "Twiggy" 5.25-inch 860 KB drives, which were '''unreliable'''; most Lisa 1s were upgraded to the Lisa 2 with a Sony 400 KB 3.5-inch drive. Twiggy read errors and disk-boot failures are why so few Lisa 1s survive &mdash; a Lisa 2 conversion or a modern floppy emulator is the usual path.<ref name="lisa">[https://lisafaq.sunder.net/single.html The Apple Lisa FAQ]; [https://tinkerdifferent.com/threads/lisa-2-repair-journey.1151/ Lisa 2 repair journey], TinkerDifferent; [https://www.classic-computers.org.nz/blog/2011-03-05-rejuvenating-a-lisa2-10.htm Rejuvenating an Apple Lisa 2/10], Tezza's Classic Computers; and the Apple Lisa Do-It-Yourself Guide. Source for the I/O-board battery-pack leakage, the PSU failure, the Twiggy-drive unreliability, and the boot-ROM error codes (40 = CPU/MMU, 57 = disk controller).</ref>
== References ==
<references />


== Related Pages ==
== Related Pages ==