I cleaned up a bunch of corrosion on a Mac IICX - in the process I replaced all the 74F258's - which I believe are used for memory multiplexing (I also replaced all the capacitors, some diodes and transistors as well - most of which is in the power control circuit).

On boot I get a frozen mouse pointer, but when I press the debug button I get a 0000000F and below that 00000013.

Anyone have any tips on debugging this? I've used a multimeter to tone out all the traces and they seem ok. In fact I only found one truly bad trace on the board (so far) - which I used a bodge wire to fix.

The only thing that worries me is that the 74F258's I used to replace the corroded ones that were there is that the originals were Motorola parts, and the replacements were made by Phillips. You pretty much can't get the Motorola parts anymore - short of paying a fortune through an obsolete chip vendor.

Here's some pictures: https://imgur.com/gallery/5uVbRsj

After a bit of googling - its possible a bad address line between the memory and one of the muxers - I guess I'll re-test.