Hi,
just got a dead Osborne 1 with a double density board. After the first tests, looks like the power supply is OK. Powering up the main board, the onboard beeper keeps beeping, and CRT monitor filament does not light.
Does the boot rom check for keyboard or disks at power up? I did not have those connected. Boot rom is just burned 1.44. Maybe next I will check the CPU signals (CPU chip itself verified good) but would like to know if keyboard or floppies are needed for boot. - Could the monitor keep its filament off because main board does not output correct sync pulses?
Tuukka
just got a dead Osborne 1 with a double density board. After the first tests, looks like the power supply is OK. Powering up the main board, the onboard beeper keeps beeping, and CRT monitor filament does not light.
Does the boot rom check for keyboard or disks at power up? I did not have those connected. Boot rom is just burned 1.44. Maybe next I will check the CPU signals (CPU chip itself verified good) but would like to know if keyboard or floppies are needed for boot. - Could the monitor keep its filament off because main board does not output correct sync pulses?
Tuukka