Apollo 1240/1260 Jumper Settings

Jumper    off (open)                   on (closed)
RAM       RAM on the Apollo board OFF      ON
SCSI      Autoboot SCSI Interface OFF      ON
060       68040 CPU Installed     OFF      060
RAM Jumper:
PLEASE NOTE: The accelerator board is only capable of high performance if FastRAM is fitted. If FastRAM is disabled, only a minimal increase in performance will be obtained.

SCSI Jumper:
The SCSI interfaces autoboot function should be switched off, if no or no autobootable SCSI devices are connected. If the autoboot function is enabled, the operation system will wait upto 30 seconds to detect any slow but bootable SCSI devices. SCSI devices can still be used with autoboot function disabled. Obviously they will not boot, but it prevents the 30 second delay occuring before booting will occur from a non-SCSI device.
CLK Jumper:
The 68040 processor has to be supplied with the double external clock frequency. A 68040RC40 (40Mhz) CPU is operated with an 80MHz crystal oscillator.

The 68060 process (with 50MHz) is operated with it's external bus frequency.

The CLK jumper is used to adjust the corresponding clock distribution as following:

68040-CPU installed            position 040
68060-CPU (50MHz) installed    position 060
68060-CPU (66MHz) installed    position 040