Apple Lisa I/O board diodes

drlegendre . drlegendre at
Thu Feb 18 19:02:25 CST 2016

FYI, I get a 403 on that link.

As for the diode, unless the leads are seriously rotted, why not just make
a +note+ of it - and leave it alone? It's a hermetically sealed package
(glass+metal, right?) and not likely to have suffered in any way, aside
from the cosmetic issue.

On Thu, Feb 18, 2016 at 6:51 PM, Adrian Graham <witchy at
> wrote:

> 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
> Cheers!
> --
> Adrian/Witchy
> Binary Dinosaurs creator/curator
> - the UK's biggest private home computer
> collection?

More information about the cctech mailing list