You say it gives you a light gray screen with the mouse cursor, but won't go any further? I don't know if this can be similar for the classic line, but on an SE/30, that same symptom means that the SCSI controller chip is bad and needs to be replaced. Either that or maybe some of the Network Resistors (labeled "RPx"; x= a number) wired to the SCSI controller chip need replacing as well.
If I remember correctly, a lot of retro Macs used that chip. It should be labeled as "53C80", with either NCR, Zilog or AMD as the manufacturers. All I can say is good luck, when it comes to replacing that chip. You would need to have a specialized desoldering station in order to properly change out the part. The Network Resistors shouldn't bee that bad, since they may still be lead-through-board type components.
To verify if it's bad, simply disconnect ALL SCSI devices internally and externally from the Classic. Restart the system and try booting off of floppies or boot off of the ROM (only works on the Classic I, not the Classic II or Color Classics). Apple + Option + X + O held down at restart will boot from the ROM. There is a copy of System 6.0.8 burned into the Mac's ROM. Don't hold it down too long or it will ask if you want to rebuild the desktop. Click cancel to stop that. If your Classic boots after doing all this, then you'll know the SCSI controller chip is in fact bad. A permanent fix is either replacing the chip or getting a replacement Classic I logic board.
73s de Phreakout. :rambo:
If I remember correctly, a lot of retro Macs used that chip. It should be labeled as "53C80", with either NCR, Zilog or AMD as the manufacturers. All I can say is good luck, when it comes to replacing that chip. You would need to have a specialized desoldering station in order to properly change out the part. The Network Resistors shouldn't bee that bad, since they may still be lead-through-board type components.
To verify if it's bad, simply disconnect ALL SCSI devices internally and externally from the Classic. Restart the system and try booting off of floppies or boot off of the ROM (only works on the Classic I, not the Classic II or Color Classics). Apple + Option + X + O held down at restart will boot from the ROM. There is a copy of System 6.0.8 burned into the Mac's ROM. Don't hold it down too long or it will ask if you want to rebuild the desktop. Click cancel to stop that. If your Classic boots after doing all this, then you'll know the SCSI controller chip is in fact bad. A permanent fix is either replacing the chip or getting a replacement Classic I logic board.
73s de Phreakout. :rambo: