dmagagno@king.mcs.drexel.edu (David Magagnosc) (01/03/91)
I am posting this mainly for my peace of mind, since I _believe_ I know the answer... Last night, my Mac II crashed and would not reboot. It would not even get to the point of displaying a Mac icon, happy or sad or otherwise, but would just sit with an entirely gray screen. I then (after some choice words and a bit of hopping around) discovered that the keyboard cable was loose in its socket (keyboard side). After I put it completely back into place, everything was fine. I think I can see that a loose connection might cause communication errors over the ADB bus which could hang or crash the boot sequence. So... 1) is this explanation (last sentence) correct? 2) is this explanation complete? That is, does this behavior indicate some other problem which only manifested itself in conjunction with the loose cable? 3) Might the attempts to boot with the loose cable cause permanent damage to components, and if so, what sort of damage might that be and why? Thanks in advance, David Magagnosc Dept. of Math and CS Drexel University dmagagno@mcs.drexel.edu
russotto@eng.umd.edu (Matthew T. Russotto) (01/04/91)
In article <1991Jan2.160301.28198@king.mcs.drexel.edu> dmagagno@king.mcs.drexel.edu (David Magagnosc) writes: >Last night, my Mac II crashed and would not reboot. It would not >even get to the point of displaying a Mac icon, happy or sad or >otherwise, but would just sit with an entirely gray screen. > >I think I can see that a loose connection might cause communication >errors over the ADB bus which could hang or crash the boot sequence. > >So... > >1) is this explanation (last sentence) correct? Don't know, but I've had it happen to me, and have concluded the same thing >2) is this explanation complete? That is, does this behavior > indicate some other problem which only manifested itself in > conjunction with the loose cable? Not that I know of-- I've seen lots of mac IIs with loose keyboard cables fail. (the ones in the public labs have security devices which allow the cable to be made loose but not removed....) >3) Might the attempts to boot with the loose cable cause > permanent damage to components, and if so, what sort of > damage might that be and why? Shorting the ADB bus can damage the mac in such a way so that the keyboard and mouse don't work (but the power key will start the mac). Probably a loose cable could cause this, but if it isn't immediately apparent, I wouldn't worry about it. -- Matthew T. Russotto russotto@eng.umd.edu russotto@wam.umd.edu .sig under construction, like the rest of this campus.