ms0p+@andrew.cmu.edu (Michael Gordon Shapiro) (02/21/90)
I have this interesting hardware anamoly that could range from trivial to serious and I'd appreciate any technically-inclined person's comments, jeers, derision, etc. Consider this: last night, as I'm wont to do, I let my computer do some autodialing and went about other business. When I glanced at the screen, at one point, I noticed it was black. "Odd," I thought to myself, and quickly reset it. (I have a 2500/20, for reference.) The computer had other ideas, however, and simply wouldn't reboot. The power light would flash, the screen would change colors (to light grey), then the power light would flash, and the screen would change colors etc etc goto 10. This was very distrubing. I tried booting in 68000 mode, and found that the machine GURUs... (810000009.41F9000F) but then works. ONCE -- and I don't know quite how -- I managed to get it to boot in 68020 mode. Since then I've been having no luck, even after turning off power, etc. Still, I am able to get the A2621's "mode list" by doing the 5-fingered salute (holding down both mouse buttons during reboot), so it can't be completely fried. Anyone recognize the symptoms? Someone tell me that a well-place Fonzie-like smack on the side of the computer will make this go away. I miss my 68020. I miss my 2 megs! HELP!
allen@grebyn.com (Allen Farrington) (02/22/90)
I too had very similar symptoms with my 2500 about a month ago. I never could get it to boot into 68000DOS but could get the DOS Selection Screen (using both mouse buttons). After about a week in the shop, they discovered that the 12V section of the power supply was almost gone -- very low voltage. Have that checked FIRST, it could save you a week of debugging. Good Luck. --Allen -- |------------------------------------------| | Allen H. Farrington (703) 222-9612 | "It's like nothing we've ever | allen@grebyn.com | dealt with before." |------------------------------------------| -Mr. Spock
daveh@cbmvax.commodore.com (Dave Haynie) (02/22/90)
In article <wZsdfei00WB5A1oGov@andrew.cmu.edu> ms0p+@andrew.cmu.edu (Michael Gordon Shapiro) writes: >The computer had other ideas, however, and simply wouldn't reboot. >This was very distrubing. I tried booting in 68000 mode, and found that >the machine GURUs... (810000009.41F9000F) but then works. A GURU when switching from 68020 to 68000 mode, without powerdown, is essentially normal. Exec won't re-check CPU type unless it actually rebuilds a significant portion of itself (which always happens, of course, on a cold boot). So the system fires up with the wrong idea of what CPU's in charge, and crashes as soon as that matters. >ONCE -- and I don't know quite how -- I managed to get it to boot in >68020 mode. Since then I've been having no luck, even after turning >off power, etc. It's hard to guess what's wrong; this certainly isn't anything like a known failure mode. The first thing I would do is open up the machine and re-seat the 68020 card. If that doesn't help things, you can at least get an idea of what could be wrong by running the monitor's memory test. Go to the mode list and type an upper-case "M". Once in the monitor, type "T 200000 400000". This will indicate a memory failure if it finds one. Ideally, the re-seating is all that's required, and that's sure enough easier than trucking the whole thing down to the service center. I would put the chance of a poorly seated card eventually working its way loose at about 100%, while there chance of a part going bad isn't non-existant, but it's not common. -- Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy Too much of everything is just enough
blgardne@esunix.UUCP (Blaine Gardner) (02/25/90)
From article <9779@cbmvax.commodore.com>, by daveh@cbmvax.commodore.com (Dave Haynie): > If that doesn't help things, you can at > least get an idea of what could be wrong by running the monitor's > memory test. Go to the mode list and type an upper-case "M". Once > in the monitor, type "T 200000 400000". This will indicate a memory > failure if it finds one. Dave are you saying that the A2620 has some built-in diagnostics? Is there some trick to accessing this monitor program and the diagnostic? After reading this I tried it without any success. I rebooted, and held down both mouse buttons to get the CPU select screen ("mode list", right?). But once there, typing "M" in ANY case had no visible effect. What should happen to show that you're in the monitor? Is this only present in certain revs of the A2620 boot ROMs? Are there any other goodies in there (assuming I can get in there in the first place)? -- Blaine Gardner @ Evans & Sutherland 580 Arapeen Drive, SLC, Utah 84108 Here: There: (My Amiga running uucp) blgardne@esunix.UUCP blaine@worsel.UUCP {decwrl, utah-cs}!esunix!blgardne utah-cs!caeco!i-core!worsel!blaine
lphillips@lpami.wimsey.bc.ca (Larry Phillips) (02/25/90)
In <1830@esunix.UUCP>, blgardne@esunix.UUCP (Blaine Gardner) writes: >From article <9779@cbmvax.commodore.com>, by daveh@cbmvax.commodore.com (Dave Haynie): >> If that doesn't help things, you can at >> least get an idea of what could be wrong by running the monitor's >> memory test. Go to the mode list and type an upper-case "M". Once >> in the monitor, type "T 200000 400000". This will indicate a memory >> failure if it finds one. > >After reading this I tried it without any success. I rebooted, and held >down both mouse buttons to get the CPU select screen ("mode list", >right?). But once there, typing "M" in ANY case had no visible effect. At the 68000/68020-Amigados/68020-Unix screen, type a capital M. Press the left mouse button and hold it, then press the right button. >What should happen to show that you're in the monitor? Is this only >present in certain revs of the A2620 boot ROMs? Are there any other >goodies in there (assuming I can get in there in the first place)? You'll know. Type a '?' to see the list of commands. -- Gallium Arsenide is the technology of the future; always has been, always will be. +-----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca -or- uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 -or- 76703.4322@compuserve.com | +-----------------------------------------------------------------------+