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[amiga_3k]

I'm not too sure if I'd learn a mobo to swim in water. Afterall, it does contain oxygen. If you'd go and give it a shot make really sure to get it 100% dry! (get it in a closed box with some Moisture Eater (shameless advertisement)and let it do its work for a week or so.

How's the 3000 doing at the moment? Did tweaking the SD/FF screw influence the output in a positive manner?

[jiminy]

I took her apart the night before and didn't get a chance to work on her last night... obligations ya know, then I spent some time digesting all the different methods people recommend for the task. Tonight, I'm going to brush all the stuff away, then put it all together and see what that does, just to satisfy my curiousity. Then, I'll see... my inclination is to follow the advice from the chemist on the 68k board and use water with just a drop of nonpolar detergent. Then maybe alcohol to remove the traces of water. My guess is, to really get everything, I'll have to remove and replace the sockets. I still haven't looked to see if it got into Agnus. Is the varnish method tried and true?

Sitting here looking at the pieces, I'm startled by how much Paula and Denise look alike. Hope the mobo shots in the hardware database can help me out...

Thanks again to all for all the knowledge. There sure is a lot here. :bow:

[jiminy]

Well, I'm a little discouraged. It's like Krishna said, the Denise chip is not making good contact. I have made things worse with my toothbrush and qtips, now I have to fiddle with Denise to get any picture at all, and it is very unstable. How can you clean the sockets? Should I just remove them and solder the chips to the mobo or get a replacement socket? Or is the damage to the traces underneath?

Now look at this agnus socket. A lot of pins are whitish especially the 4 in the corner. Maybe those are aluminum, the rest are copper and we can all be right. :-P Or is that more corrosion?



I'm not sure all the stuff can be removed with a toothbrush. It seems that some kind of solvent will have to be used.

[DigitalQ]

I'd be inclined to try some very fine sandpaper on those before I'd consider using a solvent. A fine file might also do the trick.

As for concerns about copper oxidizing, keep in mind that the bare copper ground point in the picture I posted in this thread is in a computer built in 1993. I don't see air being as much of a threat as water, acids, and strong alkalis.

[rkauer]

For the Agnus chip, use a can of contact-cleaner (found in any electronic shop).

That's will do the trick. And a SOFT teeth brush will not make any damage to the socket, either.

Just never use iron wool to clean any chip (also known as short-circuit essence).

[amiga_3k]

Sanding paper on contacts might seem like a good idea but... be aware, some contacts have a thin layer of non-corrosive metal (like gold, but I doubt Commodore used THAT ;-)). While immediately after sanding the contacts are clean and working well, system instability can occure over time.

Also... oxygen is ONE part needed for corrosion. There are other elements needed as well to get things going. But as taking air-contact away is the easiest, this is the technique of choice in many cases. Varnishing has other advantages as well, not only does it take away the air contact, it also prevents liquids (the kind that allows electrons to flow arround, enabling the corrosion process) to contact the metal to be protected. If you're really interested, you might find a document or two on Wikipedia about corrosion ;-).

[Eclipse]

rkauer wrote:
For the Agnus chip, use a can of contact-cleaner (found in any electronic shop).

That's will do the trick. And a SOFT teeth brush will not make any damage to the socket, either.

Just never use iron wool to clean any chip (also known as short-circuit essence).

I second this,
Contact cleaner will indeed clean it.
PLCC sockets sometimes need the contacts pulling out if the socket is fairly old. You should only do it if you feel confident.
I usually use something small and pointed and slightly but carefully pull the contacts inwards.
Of course it's probably just the corrosion stopping it from working though.

[jiminy]

:-)
:-o

:-(
:boohoo:

Where can I find a 8373R4 Denise chip? Or is it possible to solder the pin back in. Grrr... I guess I am fated to make every rookie mistake there is.

[da9000]

Tenacious wrote:
DigitalQ seems to have put a lot of thought into this.

Yeah, he also has admitted (in another thread) he's no good knowledge of chemistry, and further down the thread he makes the fatal mistake of assuming interconnects on components are made of aluminum.

And he obviously never tried soldering before... Anyone who solders knows that aluminum won't take solder.

He also said:

" I'd be inclined to try some very fine sandpaper on those before I'd consider using a solvent. A fine file might also do the trick."

I would tread very lightly when reading what he has to say...

Is it just me, or does it sound like eslapionage?



@Krusher:



amiga_3k:
I fully agree with your posts. I believe you explain the reason why my A3000 died: I never sealed the damaged areas and the corrosion continued.


@jiminy:

If you unsolder any of the sockets, be very careful (use a lot of flux and desoldering braid or whichever method you prefer) to remove all solder and not have to force-pull the socket out, because in case of through-holes, you can easily rip-out the wall-lining, which connects the top layer with the middle and bottom (like with vias).