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  • Posts

    • When pushing those molex connectors back into the analog board, a good idea is to put opposite pressure from the other side of the board. This keeps the board stiff and it doesn't bend away from you when you press the connector into the socket. This makes it a lot easier to not use so much force from one side.   Also, the anode cap is not hard to remove at all. As long as you have discharged it (as you stated you will), you can then get long, thin needle nose pliers under there, pinch together the metal fingers that are holding it in place, and lift up. The biggest benefit to the Mac ones is they are clear, and you can somewhat see what is going on under there.
    • Not as far as I can see, no—this will run quite cheerfully on a 68000 without any MMU at all, it's only a little bit more complicated than CP/M.  None of the assembly code seems to do anything special with distant addresses, certainly (not that I really know what I'm talking about).  So any 68k compiler ought to do, I think.  The one I'm using at the moment is insanely basic, to be honest.   I'm especially amused that the linker has no way to suppress the GEMDOS executable header in outputs so all the other tooling just works around the fact that things like the file with the master copy of the boot sector have a GEMDOS executable header on them, and it just ... doesn't copy the first 28 bytes.  This is all pretty spartan.   I'm very grateful for the Atari-targeted tools (i.e. disassembler) that I've got here, which are making this much easier!
    • I already know to discharge it at the anode cap. I've heard most CRTs from this era (should say the driving circuitry) are pretty good about discharging the CRT itself, but never a good idea to rely on that. When reinstalling the logic board in this machine, I was careful to keep my hands in the bottom part of the machine. The biggest problem for me is plugging in the molex plug coming from the analog board... sometimes I have to put a little bit of force on it to get it to snap into place properly, which makes me worry whether I'm putting too much force on the connector/board. As for the floppy/hard drive connectors, I've found that I can pull the logic board out and feed the cables through the bottom of the frame. Usually there's just enough slack in there that I can plug them in and slide the logic board back into its proper place. But, of course, the Classic has a smaller logic board and is built different from the earlier models.   That sucks about accidentally breaking the neck. That would be my worst nightmare... accidentally breaking the neck and hearing the hissing.  These old Macs are extremely rare around here (at least for a decent price) so it took a couple years just to find this one. Plus, its CRT is in really good condition. It appears to have been a low-hours machine. Will do. I'm assuming the big cable going to the CRT is the high-voltage one that goes to the anode cap? Also, isn't there a ground screw on one of the CRT mounts that must be removed?   Thanks everyone for your replies. This is making me extremely nervous, because I'm afraid I may use a little too much force or may accidentally jostle something wrong and snap! hiss! It might be a while before I'm able to actually get the analog board recapped.
    • Fast Page DRAM, 1MX1, 70ns, according to the Googles.
    • It might be useful to try out the cross-compiler just to help troubleshoot the problem.   Good luck! I don't know much about GEMDOS, but I'm cheering for this project as a spectator   Quick question---I suspect the answer is no, but does GEMDOS use the Lisa's MMU in any way? I'm guessing not (it probably just uses the flat memory space set up by the boot ROM), but if it does use the MMU, then it's possible that any old 68k compiler won't work. The 68000 can only recover from a page fault for certain instructions, so subroutine calls have to generate code that uses these instructions to "test" distant memory locations (and thereby trigger a page fault) before doing any actual work with them.