andy welburn wrote:
I have an apple 2 plus sitting here that i am trying to bring back to life, the power supply is good, that i do know, the cpu is running ok (no resets) but no video output..
Most has already been answered, however it remains to add:The rows of RAM on the board are 16K per row, so the row C is $0000-$3FFF, row D is $4000-$7FFF and row E is $8000-$BFFF. Within the rows bit 0 is to the left (column 3) and bit 7 is to the right (column 10).
The ROMs are 2K each (not pin compatible to a 2716 though, unless you have a clone board.) $F800-$FFFF is to the left, $D000-$D7FF is to the right.
The speaker should beep on power-on if the CPU is running and at least the $F8 ROM and the lowest row of RAM is populated with working chips. Typing CTRL-G should make it beep as well.
-- Linards Ticmanis The Master said, "The business of laying on the colors follows the preparation of the plain ground."