as long as I'm on the Altos thread. I'm trying to make some disks for another list member for the 8000-8200 Z-80 based machines. Both of my systems have floppy disk boot or write problems. So I decided to look into the easier machine which it a 8000-2. basic Z-80 , 1791 FDC and 2, 8" SSDD floppies. The machine will boot a single density CPM disk, read and format a SD disk, but dies if a DD disk is either inserted for boot or the format program on the SD disk is told to format a DD disk. These all have SD Boot tracks, then have to switch to DD, if formated in DD. I have the wiring diagrams and there is a "EN DD" coming off the PIO chip and goes to the 1791 chip, that never changes state. I would believe it would have a floppy density code on the 1st track to tell the OS what the remaining tracks are ??? (just a guess) I know the disks are OK, they can be read in another machine. ( just not copied.). i have looked at the data lines on the PIO chip and have replaced it just in case. I have scoped the started up circuit which also has the "EN DD" tied to it. (input) The software can only be copied by another Altos due to the disk layout. The boot ROM could be damaged?? but not knowing what it should read, its hard to guess. Can't be much there just a 2708. Anyone have a 8200-2 that can read the ROM on, or any ideas. The manual is on Bitsavers under Altos, ACS8000 users manual. The motherboard is a 8100 series (double density) Has 8000 SD, 8100 DD and 8200 in the manual. - jerry Jerry Wright g-wright at att.net