MM1
What you have to do first is look through your synth's manual to find it's SCSI number/channel... this is usually preconfigured by the manufacturer ... for example, both my Kurzweil and my s5000 sampler are set to SCSI ch6 (this is how it comes straight from the factory).
SCSI numbers are like house numbers on your street... you can't have two scsi devices with the same number in the same chain... your synth and your hard drive will require different numbers... this is stated in point #1 of the manual where it says 'Important'.
Once you've found your synth's scsi number, refer to the manual you found and set the hard drive number to anything other than the same as your synth... this may require you to add a jumper (maybe two?) across two of those JP1 pins as per the manual.. open means take off the jumper... short means add the jumper.
The hard drive motor start is controlled by pins 11 and 12 (see p82 Table 5.3) ... check to see that there is a jumper across these pins... your drive might be sleeping because the jumper across these pins is missing.
Keep in mind that setting the SCSI channel is a different thing to scsi termination... think of termination as a full stop... the synth (which is at the end of the chain) needs to be terminated but the hard drive doesn't... I recently installed a scsi card reader into my s5000 sampler... to switch off termination on the card reader, I simply had to remove a jumper from the termination pins... the sampler has a termination on/off switch on the back panel and this was set to ON.... it looks as if your hard drive termination is controlled by pins 23 and 24 so remove the jumper across these pins to switch termination to OFF.
Obviously power everything off when you do this... you'll have to re-boot each time to see the effects so it can take a while (makes you appreciate USB plug and play even more...)
Keep at it... it's a test of endurance.
The SCSI2SD card is effectively the same as a scsi hard drive... it will have its own ID and termination set to off... you connect it to your synth's internal scsi terminal with (usually) a scsi ribbon cable... it's much better because as I posted previously, more memory (depending on the size of your SD card) and no moving parts... better still, it requires hardly any power and doesn't go into idle mode... well worth the investment.