Trouble booting internal drive when external attached

[Crickster]

I pulled the internal drive from my dead LC II and plugged it into an external SCSI enclosure I had lying around.  Every time I try booting my Quadra 650 with it plugged in, it always tries to boot from the external no matter what combination of keys or number I set the drive on.

I have no other way of recovering the data from the drive outside of plugging it into my Quadra.  Any ideas on how to get around it trying to boot from it?

 

[Trash80toHP_Mini]

Can you boot from a system install on the external drive to allow you to set the internal as the boot drive in control panels?

Do you have a disk tools floppy to try doing same?

Do you have a bootable CD and internal drive or external drive to add to the chain to boot and try same?

What OS?

Not really awake yet, just asking everything I can think of offhand. Personally, I'd go with the 650/internal installation route.

 

[Crickster]

Sorry for leaving out some details. The LC II drive and Quadra both have 7.5 installed on them but when both drives are running, I get a Sad Mac (I'll get the code later).

Unfortunately I don't have any bootable media but if that'll alievate my problem I'll download and burn a copy of System 7.

 

[trag]

Sounds like a SCSI ID conflict to me.  They are probably both set to 0, and for some reason the external drive is taking priority (probably responding to initialization first).   

SCSI ID is set by three jumpers on the hard drive.   Possible values are 0 - 7, but 7 is reserved for the host (computer).   Internal main boot drives are typically set to 0 in Apple tradition (no jumpers).  

The three sets of jumpers each represent a binary column.  1's, 2's and 4's.    No jumpers = 0.   Jumper on first and second = 1 + 2 = 3.

 

[register]

The SCSI ID selector of the external drive enclosure will work only if it is wired internally to the connecting plug of the hard disk drive. This ID connecting plug is located separately from the 50 PIN SCSI connector. Else the disk drive will use the ID as set with the link plugs (jumpers) present on the drive's connecting plug, as explained by trag. Consider to check proper ID setting to eleminate a SCSI ID conflict. If this does not help, also look for proper termination.

The Quadra 650 has a drive bay to be equipped with a CD ROM drive. If the CD drive is present, check its ID setting, as well.

A bootable CD will be most useful and will shorten the amount of time you might need for subsequent system installations.