Macintosh IIfx Drive replacement

[MikMac]

My 80MB Quantum Drive died in my IIfx. I freaked because I know how many SCSI issues I have with it in the past.

The only SCSI drives I have on hand were old SCA type connector 4GB drives from old SUN workstations.

I found a great 50pin SCSI to 68pin SCA adaptor with terminator on ebay.

Terminator needed because most SCA drives have no termination as they are often connected in disk arrays.

Works like a charm!

 

[trag]

I found a great 50pin SCSI to 68pin SCA adaptor with terminator on ebay.

Is that the one a guy is selling for $19.95? I've had my eye on those for a while. That, plus something like this:

http://www.ebay.com/itm/110931454566?_trksid=p5197.c0.m619

would be a lot cheaper than a mostly free IDE drive and a (now days) very expensive SCSI-IDE adapter.

According to its Seagate datasheet, the drive I linked to above can operate in single-ended mode, but I have not purchased one in order to try it out. I'm still hoping to find a terminated SCA adapter for less than $20.

 

[CelGen]

Is that the one a guy is selling for $19.95? I've had my eye on those for a while.

Shop around ebay a lot better. You can get identical adapters on ebay for $5 or less. You also don't need the termination if your drive has it onboard.

 

[Dennis Nedry]

The Mac IIfx is the one that needs the special "black" terminators, isn't it? Does anybody know what makes black terminators different? Is it active vs. passive or is it something else? It would theoretically be pretty easy to modify a little adaptor board once to have a black terminator and then swap whatever drives you want.

 

[trag]

Is that the one a guy is selling for $19.95? I've had my eye on those for a while.

Shop around ebay a lot better. You can get identical adapters on ebay for $5 or less. You also don't need the termination if your drive has it onboard.

I have shopped around Ebay and have not seen an identical one for $5 or less than $20. However, that was one day of intensive searching. perhaps there just weren't any available that day.

I saw a few that claimed "terminated" in the subject line, but an examination of the photo clearly demonstrated a lack of components that would provide termination. Now, it could be that they're using a stock photo instead of an actual photo, but it seems more likely to me that they just copied a title they saw somewhere and pasted it on their item and don't actually have any idea what termination is or means.

Most of the SCA adapters on Ebay don't appear to support termination. Many of the SCA drives available don't have provision for on-board termination.

There is also a $5 adapter on Amazon, and again, the photo of the item clearly lacks components to provide termination, even though the item title claims termination.

If you see one ($5 terminated SCA adapter) some time, I would appreciate you bringing the link to my attention. I would love to buy some of those, but so far I haven't found any.

 

[trag]

The Mac IIfx is the one that needs the special "black" terminators, isn't it? Does anybody know what makes black terminators different? Is it active vs. passive or is it something else? It would theoretically be pretty easy to modify a little adaptor board once to have a black terminator and then swap whatever drives you want.

The IIfx terminator just adds a couple of components (caps, I think) across a couple of pins on a regular terminator. I don't remember the details, but there was an Apple Technical Note about it.

Ah, here we go: http://www.fenestrated.net/~macman/mirrors/Apple%20Technotes%20%28As%20of%202002%29/dv/dv_15.html

Apple Technical Note DV15

Also see this 68kmla discussion:

http://68kmla.org/forums/viewtopic.php?f=8&t=11554

 

[CelGen]

I have shopped around Ebay and have not seen an identical one for $5 or less than $20. However, that was one day of intensive searching. perhaps there just weren't any available that day.

Took 22 seconds to find on ebay.com.

You don't need termination on the adapter, especially in this case because the drive selected already has onboard termination. I only have seen SCA drives missing termination if they were the much newer 72+gb Ultra320 SCSI disks. I know a lot of the 18 gig had smaller drives had a jumper on the drive somewhere.

 

[trag]

Thank you. I agree that it is easy to find a $5 adapter without termination. As I mentioned in my message, I didn't have any trouble finding those. The one you just linked to lacks termination. It's finding one with termination, and preferably, one that allows terminating upper and lower bytes independently which is difficult.

If you are going to put the drive at the end of the chain, and if the drive has on-board termination, then you are correct, the adapter does not need termination. However, the drives I would like to use do not have on-board termination and so I need an adapter with termination capabilities. The drives I would like to use are also available at ten for $60 and have a 36 GB capacity.