erd@duke.cs.duke.edu (Ed Darken) (11/14/90)
Can anybody give me an idea what's going on with a flaky Mac IIci? [Assume in the following description that yes, I am turning off the system before I touch anything. I mention this because I know people who don't do that. They're scary.] We have a Mac IIci with a Quantum 105 mb internal disk and an Ehman 19-inch black and white display. We kept this system on for, oh, a month, and then its user decided to turn it off for the weekend. When he comes back, voila, the monitor doesn't work. It's getting power, there's a flash on the screen when the system is powered up, but then it goes dark. I start looking at it. I reseat the video card. This solves the problem intermittently. After repeated tests, reseating/moving the video card doesn't solve the problem. Plugging the monitor into a wall outlet instead of the back of the Mac doesn't help either. So, I plug an Apple 13-inch RGB monitor into the on-board video adapter to see if the computer is even booting when the 19-inch screen stays black like that. Guess what? As long as that RGB monitor is plugged in, the 19-inch screen works like a charm. I plug the 19-inch monitor's power cord back into the Mac (the RGB monitor is plugged into the wall). Everything works. The 19-inch screen continues to work after I remove the RGB monitor. At this point, I decide to back up the ci's disk, so I add our Apple tape 40SC to the SCSI port. Nada. The 19-inch screen doesn't work. I remove the tape drive and restart. The 19-inch screen still doesn't work. I re-install the 13-inch screen and restart. Everything works. I re-install the tape drive and restart. Now I discover that I can boot only to floppy. Everything on the bus is gone. The system won't recognize the tape drive OR the Quantum disk. My stomach starts digging a hole to China. I remove the tape drive and restart. Everything works. I install our Cache external 150 mb disk. Back to booting to floppy, with nothing on the bus recognized. I remove the Cache disk. Everything works. I thought I might be dealing with the IIci power problem that I've heard other people talking about, but the problem doesn't change when I remove the power load of the 19-inch monitor from the computer. And the tape drive and the external disk also draw their power from external sources. It seems that they're somehow dragging down the bus. Help! Ed Darken erd@lear.cs.duke.edu p.s. This Mac is running System 6.0.5, in case that helps.