I have a problem with a PowerMac 8600/200 that is driving me crazy. Let me see if I can give you all the details.

1. Some weeks ago the power supply in the 8600 died. This was replaced with a reconditioned power supply from a supply house.

2. Following this, I noticed that the computer would just not shut down. When you invoked shutdown from the special menu, the hard disks would start to spin down, they would dismount (disappear from the desktop) and then, just at the point you would expect the computer to shutdown, it would "boing" and reboot. (My energy saver control panel is NOT set to keep the machine always running.)

Configuration: Mac 8600/200 with 192 Meg ram and 1 Mb level 2 cache. The machine has the original 2 Meg Seagate hardrive that it came with, the original internal zip drive and the original internal 12x apple cd-rom drive. I have since added a 1.2 Meg quantum drive in the extra expansion slot. I also have an ATI xclaim GA card in one of the PCI slots.

3. What I have tried: The shut down problem persists whether or not I start with extensions on, extensions off, or just the basic apple extension set. The problem also persists no matter what device I use for startup. I have started from the 2 Meg seagate (with Mac OS 8.6), from the extra internal drive ( Mac OS 8.1), from CDs (running, 8.1, 8.6, 9.0), so it doesn't appear to me to be a software problem.

4. What I have tried (part B). I have disconnected the extra internal HD. I have put the original 256K level 2 cached back into the machine. No effect.

5. With the above information, we received another power supply to replace the original. Has the same problem.

6. Out of desperation, I disconnected and reconnected everything. I reset the CUDA switch and put everything back together. After putting it all back together and starting up, EUREKA, it shut down. However, after a few minutes, it reverted back to the behavior that a shut down command seems to behave like a restart. When I push the power switch on the front of the computer, it also just restarts.

So, it would seem to me to be a hardware problem, but exactly where? Motherboard? Power supply? Both? Any hope of a reasonably-priced fix, or do I just live with it?

Thanks for any help.

[wlonh]

sounds like a sketchy m'board to me

[randymc]

Did you install the PS or did some one else install it? If you did and still have access to the old one check all the pin connections and make sure it is wired right, if it is reconditioned they may have screwed up. Also check the pinouts for the right voltage with a meter or have some one else do it. You may have a bad connector where it plugs onto the MB.

[This message has been edited by randymc (edited 03-29-2000).]

I don't have the previous power supply. (A trade-in of the old one was needed.) Do you know where I might get the pinouts for something like an Apple power supply? (Although, if they screwed up, they did it twice in a row.)

[zac4mac]

Joe,
just a thought...check Apple System Profiler and see what your 8600 thinks it is... I believe this info comes from the P/S because when I put my 8500 MB in a 7500 case, ASP said it WAS a 7500...z4m
also, when you hit the CUDA, was power connected to the Mac? I believe there are 2 reset modes and with power connected there is a trickle going to the MB. disconnect power, pull the CMOS battery for at least 15 min and depress CUDA.

Thanks for your suggestions. I figured out what's causing the problem and it STILL has me stumped. The folks who installed the power supply insisted that it shut down just fine. So, my only conclusion (although it took me some time to come to this simple conclusion) is that the problem must have something to do with the peripherals. So, I disconnected everything (but the keyboard and monitor) and it shuts down just fine. To cut to the end, having my printer connected causes the computer to restart. Actually, it is one specific printer, a StyleWriter II that I have (which is the one that is connnected most of the time). If I connect my Color Stylewriter Pro, it shuts down just fine. So, my problem is solved, but I frankly don't understand it. Does anyone out there have an explanation as to how a printer can do something to make the computer restart instead of shutting down?

I had a problem with my 8600 when I had an external hard drive hooked up. So I thought. It would double-restart, that is, you had to turn it on, then Command+Control+Power to start it up again.

Wasn't the drive. Was the SCSI cable.

Try swapping the cable that runs to the printer that doesn't work with the cable from the printer that does, if you can. You might just have a damaged cable.

bestoluck,

Linda

Linda,

Actually, it's the same cable.