@orange
Yes, the corrosion is basically impossible to remove from inside the socket contacts. By attempting to clean it, you only stretch the socket contacts, making things even worse.
The only thing better than replacing the sockets with new ones, is removing the sockets and soldering the ICs directly into the board.
Those sockets are truley hideous, just a general cause of problems all round, even without leaking batteries to make things worse.
My advice is that if any socket contacts have any hint of green in them, the socket needs to be replaced.
It may work fine today, but start causing intermittent problems tomorrow.
There's an easy technique for removing those sockets and minimising risk of damage to the PCB.
I think I've explained it in another thread somewhere, but can re-iterate if you like.
@melange
Fault finding by measuring continuity like you're trying to do can work, but as you'd have already noticed, is very time consuming.
If you want to do it that way, you need to measure from the leg on the IC body, to another known good contact elsewhere.
That can give you incorrect readings, as when you press down on the IC leg to measure it, it presses the leg into the socket, perhaps making temporary contact just while you're measuring it.
A much faster way to fault find is to run the machine and check for signal activity on appropriate IC legs using an oscilloscope. This is the method I usually use for finding such problems.
The problems there is you need an oscilloscope, and you need a good idea of what you're looking for to begin with on each signal line.
But for your problem, the best approach would be to replace sockets which are corroded and in the process, carefully check continuity on tracks which are suspect. As in tracks which might be corroded, ones which run through the RTC area and especially tracks which run to vias near the RTC area.
I drew a crappy wee diagram which explains via corrosion and how to repair them:
http://amiga.serveftp.net/images/ViaRepair.jpgThis is more of a problem in A4000, though it's worth being aware of it. The A3000's PCB uses a slightly different method to track between layers which is more robust to corrosion.
And just how did you manage to damage so many IC legs? :-P
There are tools for removing DIL devices such as those, which are cheap and work well. Shaped like a large pair of tweesers with 90° hooks at the ends.
