I am hitting my head against a wall and need some help. I have been dealing with a IIGs memory expansion board model 670-0025 for over a year and a half and enough is enough. I need help. I cant find a schematic for this board.
I got the boad and it was not working, It was a bit crusty but but nothing otherwise of note. I determined to TTL logic chips failed and replaced them. But since the solder was so old and crusty desoldering was a problem and a few traces lifted and broke. I bodge wire fixed 3 bad traces but here is the problem. The card "works" but only up to 512KB, it WILL NOT detect the other 512KB of chips in the card. Yes those chips are 100% working I already checked that. I have other working boards of the same model and I have been trying to continuity check every connection but its intolerable. I need a schematic and some advice as to what possible line is broke to inhibit the other (lower) 512KB of RAM from being seen.
Please help, I want to be done with this card!!!