Apple Lisa I/O board diodes

[Alexandre Souza]

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2016-02-18 22:51 GMT-02:00 Adrian Graham <witchy at binarydinosaurs.co.uk>:

> Hi folks,
>
> 'Decaying battery' panic led me to unearthing my Lisa 2/5 to check the
> state
> of the batteries on the I/O board since it hadn't been out of its box or
> powered up since 2005. Fortunately the damage is very minimal and is only
> restricted to track discolouration and external rotting of one particular
> diode which I can't find mention of on my schematics.
>
> Anyone with a 2/5 care to check their I/O board for me please? The diode is
> D8, just above the battery location. It's in the board in such a way as to
> make its markings pretty unreadable in the pictures I took before cleaning,
> but it's the only white diode in the machine and I'm guessing it might be a
> 5.6V 1N4734A based on what I can see. Fortunately it still works for now,
> 0.7V voltage drop.
>
> Pic of the board before cleaning is at
> http://www.binarydinosaurs.co.uk/LisaIOBoard.jpg
>
> Cheers!
>
> --
> Adrian/Witchy
> Binary Dinosaurs creator/curator
> Www.binarydinosaurs.co.uk - the UK's biggest private home computer
> collection?
>
>
>