[Tech] An unusual method of computer repair

I have managed to repair my Mac Classic II, which makes me happy. After a few incidents of Simasimac when powering it on, overcome by trying a few times, it died altogether a month ago.

But I did it in a strange and unfamiliar and rather scary way. I took out its logic board, removed its SIMMs & carefully pried its 4 DIL ROM chips out of their sockets...

And ran it through a cycle in my dishwasher.

After that, I carefully scrubbed the worst-damaged areas of its logic board with an old toothbruh and lots of hot water, dried it thoroughly overnight in the airing cupboard, reinserted it...

And it worked! My compact Mac bonged happily and booted successfully first time!

Good news for me, bad news for technofairy, who wanted to make it into a Maquarium.

But why did this work? ( Read more... )

How capacitors REALLY work

By way of an update to my earlier post. Mailing list correspondent Doug McNutt sends this correction:

That's a bit of oversimplification in a helpful description aimed at less than engineering folks. The "short charge/discharge cycle" is misleading because it implies electrochemistry.

An aluminum electrolytic capacitor depends on a very thin film of Al₂O₃, aluminum oxide, which is formed by passing a DC current through the metal and an acid, usually sulfuric, which is placed as a paste between the aluminum foil "plates" as they are wound into a cylinder with some paper spacers.
( Read more... )