sirolly10@wharton.upenn.edu (Michael Sirolly) (03/05/91)
Speaking of 512K upgrades, I've had a wierd video problem ever since I performed mine. For background, it was a board with 120 ns chips that I put in by the "remove the 128K and clip the two capacitors" operation. The memory seems to work fine, but since it was installed my CoCo has been fidgety about switching video modes. If the computer has been on for a while, a BASIC command switching HSCREEN's or PMODE's, or running any program that does the same, is risky and may send the computer off into la-la land. Sometimes it doesn't lock up right away, but the graphics screen comes up with scattered pixels that weren't cleared or were cleared wrong. Similar shrapnel of the operation is distributed througout memory, vandalizing BASIC progams and corrupting BASIC or the application itself. Even if the computer is just turned on and still completely "cooled off," a direct statement like: FOR X=1 TO 1000:WIDTH 80:WIDTH 32:NEXT X ..will kill the thing in a matter of seconds. However, under OS-9, it is usually possible to set up as many windows under different screen modes as desired and hold down the [CLEAR] key to rapidly flip between them - without incident. Add in Multiview and do the same thing, and disaster will come rather quickly. Any ideas where my CoCo's problem might be? Michael Sirolly "SIROLLY10@wilma.wharton.upenn.edu"
halkoD@batman.moravian.EDU (David Halko) (03/16/91)
In article <1991Mar4.151832.1@wharton.upenn.edu>, sirolly10@wharton.upenn.edu (Michael Sirolly) writes: > > Speaking of 512K upgrades, I've had a wierd video problem ever > since I performed mine. For background, it was a board with > 120 ns chips that I put in by the "remove the 128K and clip the > two capacitors" operation. > > The memory seems to work fine, but since it was installed my > CoCo has been fidgety about switching video modes. If the > computer has been on for a while, a BASIC command switching > HSCREEN's or PMODE's, or running any program that does the > same, is risky and may send the computer off into la-la land. > > Sometimes it doesn't lock up right away, but the graphics > screen comes up with scattered pixels that weren't cleared or > were cleared wrong. Similar shrapnel of the operation is > distributed througout memory, vandalizing BASIC progams and > corrupting BASIC or the application itself. > > Even if the computer is just turned on and still completely > "cooled off," a direct statement like: > > FOR X=1 TO 1000:WIDTH 80:WIDTH 32:NEXT X > > ..will kill the thing in a matter of seconds. > > However, under OS-9, it is usually possible to set up as many > windows under different screen modes as desired and hold down > the [CLEAR] key to rapidly flip between them - without > incident. Add in Multiview and do the same thing, and disaster > will come rather quickly. > > Any ideas where my CoCo's problem might be? > > Michael Sirolly "SIROLLY10@wilma.wharton.upenn.edu" Well, I have had a similar problem at one time... mine was due to excessive heat and a bad power supply... immidately after moving my system to a PC case, it disappeared... you may just try a big muffen fan from Radio Shack to solve that problem... Dave Halko
darren@revcan.UUCP (Darren Morbey) (03/22/91)
In article <3176@batman.moravian.EDU>, halkoD@batman.moravian.EDU (David Halko) writes: > In article <1991Mar4.151832.1@wharton.upenn.edu>, sirolly10@wharton.upenn.edu (Michael Sirolly) writes: > > > > FOR X=1 TO 1000:WIDTH 80:WIDTH 32:NEXT X > > A similar problem appeared in THE RAINBOW magazine. Marty Goodman believed that the problem was with the GIME chip -- 1986's were supposedly flawed. If yours is dated '86, he advised putting in a later model chip (if they are still available.) I don't have the issue in my hand right now, but I believe it was early 1989 when he wrote that (January or March.) Does it help? Darren Morby.