At 16:04 -0800 2/4/04, Jennifer Worgan wrote in response to: Do recent Classic II's read 800K discs or run 68K software? >Dishwashing soap is alkaline, battery leakage used to be acidic until >alkaline batteries came out. I can't speak about the capacitors, I don't >believe I have heard of a resistor leaking anything other that electrons due >to a crack in the resistor causing the resistor to fail or working only when >there was enough charge to cross the break.
Aluminum electrolytic capacitors depend on a layer of Al2O3, aluminum oxide, for the dielectric layer. They require an acidic "wet" paper to produce it. The acid is proprietary to the manufacturer but anodized aluminum drinking cups use 10% sulfuric. The procedure is to put rated voltage on a "green" capacitor. Electrolysis causes the insulating layer of Al2O3 to form and create the capacitor. Old electrolytics can typically be restored to use by applying rated voltage for a week or so while they develop the Al2O3 layer > I don't believe diodes, >transistors or chips leak or melt a residue. They don't. There are no liquids involved on a silicon chip. > That's the end of my high >school electronics - come on guys, what are we working with? cigarette smoke >tar film? Perhaps. There are lots of "proprietary" items in the world. >Some engineer out there may be able to give us an insight as to the >chemistry we need - such as the nature of the component residue that can >affect the electrical perfomance of the board. Some chemist could then tell >us what would do the job the best to clean it. I'm trying, but there are gremlins out there. Someone pointed out that leakage from aluminum capacitors might short out traces on PC boards and that is why dishwasher cleaning works. I donno about that but it is not unreasonable. If true then an alkaline wash with soap makes sense to neutralize the effects of leakage from aluminum electrolytics. NaHCO3, sodium bicarbonate, as used in the kitchen, is another common neutralizer for acidic contamination. Another option is to remove the aluminum capacitors, clean out below them and replace. But which, of the dozen or so, require replacement is a nasty problem. In any case, full neutralization of the alkaline effects of the soap are a requirement. Lots of rinsing in fairly hot water makes sense. Transistors and integrated circuits have a common limit of about 200 degrees C before serious changes to the solid state electronics occur. But then the water itself is bad. One way to get rid of that is to flush with dry alcohol. Ethanol is best but it requires a license. Isopropenol is easily available but the kind you get in a grocery store is loaded with water and called rubbing alcohol. Professional cleaning suppliers will sell dry isopropyl alcohol for a buck or two a gallon though they don't know what they have. The plastics in things electronic are specifically selected to be resistant to ethyl, C2H5OH, and propl, C3H7OH, alcohol. My personal experience is with a bunch of printed circuit boards that were built to perform in a rocket. It was launched from Wallops Island VA and the recovery system failed. The photographic film on board and the electronics were recovered from the deep using techniques I can't talk about. We cleaned the PCB's and the film with distilled water using an ultrasonic cleaner. We then dried them in ethanol and pretended that the recovery was accomplished as intended. Recovery of data, both photographic and electronic, was essentially complete. SE/30 boards in an ultrasonic cleaner with distilled water. Worth a try. But I don't have access to that laboratory anymore. -- --> There are 10 kinds of people: those who understand binary, and those who don't <-- -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
