electrolyzing a TB-303 (weird repair story)

[Magnus Danielson]

From: "Heiko van der Linden" <h.j.vanderlinden at el.utwente.nl>
Subject: electrolyzing a TB-303 (weird repair story)
Date: Mon, 25 Sep 2000 10:41:17 +0200

> Hi all,

Hi there...

> Then after desoldering one sixth of the main board I cleaned it and the red
> residue was
> rust. So the next thing was to check where the rust came from. And here
> comes the weird
> part: two of the RAM chips had both their pins 20 eaten away. Since pin 20
> is the plus pole
> the only thing that comes to mind is that the rain water was electrolyzed
> during the 5 minute
> turn-on period. This caused acid to be generated at the plus pole which in
> turn attacked the
> chips' pins and causing the red residue and the failure.

Hum... if it where acid, then this TB-303 is a REAL acid-box! ;D

> The reaction would be: 2H2O ----> 4H+ + 4e- + 02.

Actually, when you do this my experience is that most metal gets eaten
away by the oxygene and little free oxygene gets away. However, not
uncommonly will a lot of hydrogen gas be emitted.

Naturally, that is my experience from trying electrolysis as a child.

> I have never seen this kind of "weird" stuff but it seems to me that it's a
> good hypothesis because
> only the plus pins were eaten (nothing else on the whole board).
> After cleaning, resoldering the whole thing and reassembling it. I plugged
> the wall wart into it and
> it functioned again. And my friend became very happy again instead of
> looking at the wall paper the
> whole time.

Ah, good that you after all where able to make it go
alive... otherwise you would have to find him a suitable forrest to go
and scream in...

> Has somebody else seen this defect ? Is this common to electrical devices
> that have been exposed
> to water ? It must be I guess.
> 
> Greets and thanks to listening to my story (maybe we should start a
> synth-diy cafe for this kind of bar talk ;-)

I think the synth-diy bar is the right name... or maybe it's the
"nigth-hour" session that you use to scare the kids with...

Hum, this story made me recall when I had to save half a studio
(including the band-machine) when it started to rain Coca-Cola
concentrate from the ceiling!!!!!

Luckilly we where able to keep the equipment away from it...

Cheers,
Magnus