On Sun, Dec 25, 2022 at 5:32 PM Bill Degnan <billdegnan_at_gmail.com> wrote: > > I believe you need to load on a IEEE 8050 and or 8250 (sfd-1001), but I am not sure if it works on both. Less likely on a 4040 1541. But, it's not a disk image so maybe there is something wrong with the PRG file. If anyone else tries It I'd like to know so I can fix the image. I've just written the program to a 4040 disk since that's all I have and cbmlink can't write a program directly to tape. I haven't tried to add the load address yet as I decided first to check both the drive mechanisms. I think the program will ask for a drive number to be tested. I've found an 8050 diagnostic too and it loads some machine code into the drive then executes it and that seem to indicate a bad DOS ROM, but it seems to me that 8050 ROM code is different from the 8250LP's one. These ROMs also have active-high chip selects so I can't read them on a regular EPROM programmer to verify the content unless I make an active adapter with an inverter gate. I think the ROM content can be read by M-R commands, right? I have dismantled the 8250LP's drive 0 to change capacitors and repair the traces damaged from the leakage. I've also noticed that probably some sockets on the digital PCB need to be changed. The "drive controller" 6502's didn't seem to work well, so I've substituted it and the behaviour changed. However the original 6502 worked fine in my PET, so it must be a socket issue. These things need a lot of time... FrankReceived on 2022-12-25 19:00:02
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