sicklittlemonkey wrote:
Hi Phil. Looking at your original post again, it is very strange that your original problem restored itself *only* when you replaced the original RAM. If the stack RAM was hosed, the CPU might spin endlessly, but with either set of RAM, there was no beep right?
The difference is likely just the "random" power up state of the DRAMs, which is displayed on the screen. Upon RESET, the first thing the II does is set a couple of flags in memory, then set text mode, which clearly isn't happening from the look of the display. This all happens about a dozen instructions into RESET, so the processor isn't making much headway... -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."