I'm looking for suggestions on where to focus my efforts. My logic analyzer is in the shop and won't be back until next week, but I have time to work on this over the weekend.
I have two Apple IIc mother boards. Both appear to be fully functional.
The first board works fine with keyboard, disk, serial, etc.
The second board works fine with keyboard, disk and... sorta, serial.
If I hook up a serial line to it and do an IN#2, I can type characters across with no problem at 9600 or 19200 baud. However, if I use something like ADTPro to stream a boot disk, some comes through ok but lots and lots is garbled.
I spent a lot of time swapping cables, swapping USB serial adapters, etc, and finally decided to hook up the other board, discovering that the other board receives serial data with no issues at all.
The big problem is that there's nothing visibly wrong with the board or components and the serial issue seems "intermittent", but not so intermittent that I can successfully transfer anything over serial.
Thoughts?
I have two Apple IIc mother boards. Both appear to be fully functional.
The first board works fine with keyboard, disk, serial, etc.
The second board works fine with keyboard, disk and... sorta, serial.
If I hook up a serial line to it and do an IN#2, I can type characters across with no problem at 9600 or 19200 baud. However, if I use something like ADTPro to stream a boot disk, some comes through ok but lots and lots is garbled.
I spent a lot of time swapping cables, swapping USB serial adapters, etc, and finally decided to hook up the other board, discovering that the other board receives serial data with no issues at all.
The big problem is that there's nothing visibly wrong with the board or components and the serial issue seems "intermittent", but not so intermittent that I can successfully transfer anything over serial.
Thoughts?