gmark@cbnewse.att.com (gilbert.m.stewart) (11/06/90)
My coco seems to have died. At powerup, ampersands and such appear on the screen, whose black border and green background look normal. I guess it's the ROM. Anybody know where the cheapest place to get a coco I ROM nowadays? Since the background looks okay, can I safely say it's the extended BASIC ROM rather than the "stock" original ROM? - G. Mark Stewart ihlpq!gms 708-979-0914 1200 E. Warrenville Rd. Naperville, Il. 60566
jal@acc (John Lauro) (11/06/90)
In article <1990Nov5.215152.28456@cbnewse.att.com> gmark@cbnewse.att.com (gilbert.m.stewart) writes: >My coco seems to have died. At powerup, ampersands and such appear on >the screen, whose black border and green background look normal. I >guess it's the ROM. Anybody know where the cheapest place to get >a coco I ROM nowadays? Since the background looks okay, can I safely >say it's the extended BASIC ROM rather than the "stock" original ROM? > I never seen a ROM in a CoCo go bad. To me, it sounds more like the SAM chip or CPU. It could also be a memory chip, but that would tends to cause mostly everything to be the same (like an &), but have a some characters different. - John_Lauro@ub.cc.umich.edu
SJS132@psuvm.psu.edu (11/08/90)
Maybe he aught to scrap the CoCo I and just get a CoCo III.. Worth it at
only 99$ (I saw them on saw the other day...)
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/--------------------------------------------------------------------------\ingoldsb@ctycal.UUCP (Terry Ingoldsby) (11/09/90)
In article <1990Nov5.215152.28456@cbnewse.att.com>, gmark@cbnewse.att.com (gilbert.m.stewart) writes: > My coco seems to have died. At powerup, ampersands and such appear on > the screen, whose black border and green background look normal. I > guess it's the ROM. Anybody know where the cheapest place to get > a coco I ROM nowadays? Since the background looks okay, can I safely > say it's the extended BASIC ROM rather than the "stock" original ROM? First of all, which CoCo are you referring to? I am guessing that you mean Coco I or CoCo II. In any case, it is unlikely that the ROM would go (unless you have been tinkering around inside and managed to short something). Much more likely is the CPU or (if it is a CoCo I/II) the SAM chip. Your VDG is quite capable of producing video output without CPU, ROM, RAM or SAM in the system. It will come up in some default mode, and as long as some power and timing conditions are met will display the data it sees on the data bus while the address lines are clocked through certain values. My guess is (I don't have schematic or specs handy) is that some value is locked on the data bus (perhaps NULL? I think that gives inverted @ ??) and that your VDG is just clocking them out to the screen. What usually kills CoCos is unplugging a ROM cartridge with the power on. That can toast your CPU or SAM chip. Hope this helps. -- Terry Ingoldsby ctycal!ingoldsb%cpsc.ucalgary.ca Land Information Services or The City of Calgary ...{alberta,ubc-cs,utai}!calgary!ctycal!ingoldsb