Term Power and the Performa 630

[Phipli]

I always thought the logic board provided termination power in Macs, but my Performa 630s (two of them) will only boot (gets to Welcome to macintosh, then stops, mouse still moves) with a CD Drive installed if I enable the Term Power jumper on the back of the drives.

Obviously I don't want to supply termination power from two places on the bus so, does anyone know what is going on? Do you need to enable Term Power on the CD in a 630?

@Durosity @joshc @Bolle @MrFahrenheit @croissantking - any idea? How are the CD Drives in your 630s jumpered? Remember you have to remove the metal cover over the hard disk before the CD Drive pulls out

 

[bigmessowires]

Term power jumper? Pardon my ignorance, but are you sure that's not a termination enable/disable jumper?

 

[Phipli]

Term power jumper? Pardon my ignorance, but are you sure that's not a termination enable/disable jumper?

Fairly sure. I'd be disappointed in Panasonic if they labelled the termination jumper as Term Power, given that is a thing, plus I checked a manual for a similar Panasonic drive.

 

[Phipli]

Term power jumper? Pardon my ignorance, but are you sure that's not a termination enable/disable jumper?

Does your 6300 have a CD Drive fitted?

To remove it, take the plastic front off the computer, remove the small metal cover from the hard disk, then lift the plastic latch under the CD drive and pull. If it doesn't come easily, wiggle it from side to side.

The CD drives just plug into edge connectors at the back on these, no cables.

Then if you have a look at the jumpers, the one on the end of the block of them is usually Term Power, if you have the usual Apple drive (Panasonic / "Matshita").

 

[Phipli]

 

[bigmessowires]

Yes, the jumper at the far right labeled "term power" is installed on mine. I would imagine "term power" means it enables the connection from the SCSI bus term power to the drive's active terminator, thereby enabling termination.

 

[Phipli]

Yes, the jumper at the far right labeled "term power" is installed on mine. I would imagine "term power" means it enables the connection from the SCSI bus term power to the drive's active terminator, thereby enabling termination.

I don't think it is.

 

[Phipli]

Yes, the jumper at the far right labeled "term power" is installed on mine.

Thank you for clarifying yours is also set like this, it must be a thing on this case / board family that the drive provides the termination power, not the host.

I'm happy that I'm not just backfeeding power into the 5v rail on the PSU now.