jnp@calmasd.GE.COM (John Pantone) (08/15/88)
I have been using my Mod 4 for 5 years now - without so much as a
glitch - one of the most useful and reliable machines I've ever used;
until yesterday! :-(
Symptoms: Put boot disk in drive - Power up - Drive light comes on,
drive spins - garbage on screen and no boot. Cannot boot in Mod I
mode (reset switch while pressing break key) either. I have tried
several LSDOS boot disks, and several CP/M+ boot disks - same results.
Fried ROM? Anybody have such a problem? Any guesses about price for
repair?
E-mail please.
--
These opinions are solely mine and in no way reflect those of my employer.
John M. Pantone @ GE/Calma R&D, 9805 Scranton Rd., San Diego, CA 92121
...{ucbvax|decvax}!sdcsvax!calmasd!jnp jnp@calmasd.GE.COM GEnie: J.PANTONEditto@cbmvax.UUCP (Michael "Ford" Ditto) (08/19/88)
In article <2722@hubcap.UUCP> oolidjr@hubcap.UUCP (Joe Moll) writes: >From: jnp@calmasd.GE.COM (John Pantone) >> >>Symptoms: Put boot disk in drive - Power up - Drive light comes on, >>drive spins - garbage on screen and no boot. Cannot boot in Mod I >>mode (reset switch while pressing break key) either. >First of all, you prob. don't have any ROM problems. The ROMs used in >the old Mod 3's and Mod 4's are tanks. You prob. have a dead disk >controller chip. I had the same trouble with my old Mod 3 and the new >chip did the job. I am assuming that the "garbage on screen" is normal alpha&graphic characters in 16x64 or 24x80 format, rather than static or a rolling picture or something like that. I seriously doubt the disk controller diagnosis... Based on my experience hacking ModI/III/4 hardware, garbage on the screen and drives spinning mean that the CPU can't run the boot code. Unfortunately, this could be caused by almost anything, like bad RAM, bad ROM, or a bad CPU. About the only things you don't have to suspect are disk, video, and power supply. Likely and/or easy things to suspect/replace would be RAM, CPU, and anything that is socketed. CPU's don't flake out very often, so I'd suspect RAM first, then anything that might have been replaced recently. If you have 128K, try swapping chips from the first bank to the second. Sorry I can't give an easy solution. -- -=] Ford [=- . . (In Real Life: Mike Ditto) . : , ford@kenobi.cts.com This space under construction, ...!ucsd!elgar!ford pardon our dust. ditto@cbmvax.commodore.com