All,
I purchased an Apple III which displays the attached screen rather than booting.
I tried the following to no avail:
- reseated all chips, including all memory chips
- cleaned up some rust and residue wherever I could see on chips (some was around floppy connection; worst looking was chip 341-0035-00 which, however, seems to be keyboard encoder, so probably not the culprit)
Any ideas how to proceed fixing this machine are welcome.
I don't know a lot about a III, but does it do the same self test as the IIe when the keyboard is not attached? If it throws an error it might be easier to track down.
Thank you Spectre. No, actually it never makes it to the self test — this screen appears right on power on.
Apparently your next port of call is.. Get an O-scopeand check to see if the clock line is getting pulsed on the CPU...
Thank you Spectre. I happen to have an oscilloscope even though I am far from skilled using it... let me find Apple III motherborad schematics and technical description, and let me try. I'll update the thread when I know more.
Thank you Spectre. I happen to have an oscilloscope even though I am far from skilled using it... let me find Apple III motherborad schematics and technical description, and let me try. I'll update the thread when I know more.