Mac Classic II logic board problems.

you can try it to look for another logicboard from ebay.it is easy and simple thing.

like dirty, and any corrosion that might have occurred due to component leakage.

Sometimes, the corrosion will short out pins and components causing a drop in current, or current not flowing the way it should. that causes problems that mean the computer either doesn't work reliably, or doesn't work at all.

I recommend distilled water. Less contaminants like lead and zinc, etc... that is found in tap water.

The question is, if the washing works, how long before leakage runs the motherboard foul again? Any permanent fixes besides replacing components?

1 of mine lasted a few weeks, the other 2 have been running well for at least a year. Maybe 2

I think the aerosol spray that Jon had suggested in my Kiwi post on the same problem was some type of sealant for the capacitors. Jon, where are you, buddy?

Well, I'm here now. For the time being I don't recall exactly what I posted, but I'd guess it was something like electrical parts cleaner or some such. Sometime I run into a issue and I can't remember how I solved it in the past. My memory fails me in many ways, and surprises me in others...

The question is, if the washing works, how long before leakage runs the motherboard foul again? Any permanent fixes besides replacing components?

Isolated cleaning -- identifying a failed component and cleaning around it with distilled water and alcohol -- will work for a while, until the component (99% of time capacitor) fails completely or another one goes. Radical cleaning of the entire board keeps it running longer, because you are delaying more than one capacitor failure. Ultimately, you'll need to replace all of the capacitors when they reach complete end of life. How long? It depends on climate, Mac usage etc. My guess is that there will be a modest business for refurb Mac SE/30, Quadra, IIci, IIfx logic boards in the future.