I take it you have a physical terminator at the end of the cable?

On my 2.1 50 pin Hawk drive all jumpers are removed. No external termination on the hdd at all and works perfectly on my isa adaptic controller. I was having a similar until I pulled all the jumpers. Sounds counter intuitive but it worked.

some drives and devices have termination jumpers, but my experience while not that experienced, its usually things like zip, tape, scanners, cd drives etc that can either terminate through a jumper or have physical terminators like a plug in the case of like a scanner.

My experience with hard drives is that scsi was designed so that you can as many drives on a chain so long as you have available IDs to assign them and you need a terminated cable at the end of the scsi cable.

Reason why it might of worked OK on the ISA card is maybe because on some 50 pin devices that is single device only so it never asks or cares about termination i really dont know.

What i do know is on my 68 pin U320 setupts i abolutly need to have a terminator pluged in to the end of the cable and actual physical terminator or it wont work. Simply just setting a bios setting that says termination is not the same. and there is a difference between 50 pin ribbon single ended scsi and 68 pin LVDS and thats why you need a terminator,

Do you have Term Power enabled on the drive (and Term power to the bus) ? Also some 68 to 50 pin adapters just don't work well from my experience, can you borrow one that is known to work.

Thanks for the replies.

Basically this is how I had it set up:

1[ISA SCSI Controller]------ 50-pin ribbon cable ------[50 to 68 pin adapter][68 pin HDD]

In the controller BIOS, I set termination to "Enabled" since the card is at one end of the bus (no external devices attached to it).

On the HDD, I set the "Termination Enable" and "Termination power to HDD" so that the active terminators in the hard drive are enabled and powered (these are the default settings).

Horun wrote:

Do you have Term Power enabled on the drive (and Term power to the bus) ? Also some 68 to 50 pin adapters just don't work well from my experience, can you borrow one that is known to work.

I did not set the "Terminator power to SCSI bus" jumper in the HDD, do you think this may help?

Warlord wrote:

I take it you have a physical terminator at the end of the cable?

No, I do not have a physical terminator, I assumed I didn't needed them since both the card and the HDD provide built-in active termination.

Caluser2000 wrote:

On my 2.1 50 pin Hawk drive all jumpers are removed. No external termination on the hdd at all and works perfectly on my isa adaptic controller. I was having a similar until I pulled all the jumpers. Sounds counter intuitive but it worked.

I tried removing the HDD termination jumpers and it doesn't work, either in the middle of the chain with a terminated 50pin drive at the end, or by itself.

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Now, I have done some further research and it looks like I may need an adapter with "upper byte termination", so I started to browse but I feel like I'm drowning in a sea of adapters and cables. If SCSI gear was cheap I would just buy a bunch of them and try different arrangements, but with many of these sellers online trying to charge like $40 for a cable it's difficult for me to gauge what may work in this case as I have no experience in SCSI land.

So, since I also have a 68 pin cable that works well with the HDD when connecting to a PCI controller and my current adapter being apparently useless, I could try purchasing a female-to-female 50 to 68 pin and connect it this way:

1[ISA SCSI Controller][50 to 68 pin adapter]------ 68-pin ribbon cable ------[68 pin HDD]

Would this scenario have some chance of working? I think it's pretty much the same as the other one, but at this point I just don't know.

In case I buy physical terminators, which ones would you guys recommend? I see wildly varying prices... And what connection layout would you suggest? I just want the controller and the HDD, nothing fancy.

my honest opinion is it's probably not worth your hassle. just throwing things together and rigging them to work is fine if it works and it meets whatever standards that the person doing it has. Theres nothing wrong with that but its objectionable in that if you insist on using scsi to just go the scsi to SD route since in the long term this is a better solution.

Warlord wrote:

my honest opinion is it's probably not worth your hassle. just throwing things together and rigging them to work is fine if it works and it meets whatever standards that the person doing it has. Theres nothing wrong with that but its objectionable in that if you insist on using scsi to just go the scsi to SD route since in the long term this is a better solution.

I know SCSI2SD would be a simpler option, but my issue with it is basically price, as most of what I have now (NOS HDD, controllers, cables) I got pretty much for free, I only spent about 5 bucks on the adapter. It's not that I specifically set out to build some SCSI extravaganza, just wanted to use this stuff and a 486 machine seemed ideal for a 1GB drive. But I didn't realize connecting a wide drive to a narrow controller would be so convoluted, I thought the only downside of doing that would be running at a slower bus speed than what the drive supports.

So it looks like I'll put this project on the back burner for now, at least until I can properly identify which connectors/adapters I should use.

I do have some 50 pin IBM drives I could use if I wanted a SCSI build desperately, but they're so obnoxiously loud that I consider them unusable, while this 68 pin Seagate is not louder than most IDE drives of that time.

I have some scsi stuff laying around, and see if I cant get a s8pin hard drive to wrok with a 50 pin controller. I think your main problem is that you don't have a proper scsi cable. pretty sure about that.