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!!!
You do know that you can get a new 8MB board for $35 w/free shipping, right? Also draws MUCH less power and creates almost no heat!
GW4201D on eBay.
Hi Jeff, I am aware of those boards. But I still have a few of these 1MB boards and lots of RAM chips for them. Repairing them is also the fun of this hobby for me. Plus I dont like waste, If I can fix it, I will. I just really need to find schematics. They must be somewhere.
See this is what bothers me. No one chiming in means there ARE NO schematics out there... It is beyond stupid and promotes a throw away culture if things aren't given a chance to be repaired. Its infuriating. I have already ran into this problem with Apple Color composite monitors.
I also did a search, but came up empty. So, this is where YOU can decide on it's value.
If you want to draw up a schematic for it and share with the A][ community, that would be great.
If you're unable to unsolder the components from the board to expose the traces, I'm happy to help you with that - gratis.
I've done this several times before and have the professional extraction equipment and expertise to do so. Just let me know.
Hi MacNoyd, Technical writing is not really a skill I possess. As far as desoldering I have desoldered all but the ram sockets which I am 90% certain are not the issue as the original problem was bad TTL logic (removing them caused lifted broken traces) So it has got to be a problem on the logic side of the board. And my eyes are not what they used to be so a schematic would have been the ideal choice for connection points.