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80 pin -> 50 pin SCSI adapter in SE/30

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So, I have a 1gb 80 pin SCSI hard drive I wanted to use in an SE/30. So I bought an 80 pin to 50 adapter for it. However when I boot up the system with disk tools floppy, Apple HD Setup does not detect any SCSI devices. The only thing I can think is I have to mess with jumper settings. The adapter came with 2 jumpers, and these are the pins on the adapter:




Any idea on what pins need jumpers? Thanks!

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Hard Disk Toolkit


The Mac's controller is SCSI ID 0, so you'll most likely need a jumper on ID 1 or ID2 as the Adapter/Drive's identifier on the chain.

If your HDD has an ID jumper installed, you've already got a bit of SCSI Voodoo going there.

Dunno about the rest, but that activity header definitely needs an LED lead! ;)


Got a clearer pic or docs to scan? :?:

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The Mac's controller is SCSI ID 0, so you'll most likely need a jumper on ID 1 or ID2 as the Adapter/Drive's identifier on the chain.


Mac itself (initiator) is always ID 7. Internal drive that consists System folder traditionally is set to ID 0.

So, Brooklyn, if this drive is your only drive, no jumpers on ID pins are needed.

BUT, unless your SCA adapter has onboard terminators, you have a problem.

SCA drives do not have any kind of onboard termination, but your SCSI chain in SE/30 needs to be terminated. Solutions to this problem would be:

1. Use different internal cable (with one extra connector) and use 50 pin terminator that attaches to that cable.

2. Use 'pass-thru' terminator (see below) on exsisting cable.






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Thanks for the correction, o, I hadn't had coffee yet and must have got SCSI IDs mixed up with PseudoSlot IDs . . .

. . . if that's not right either, my next excuse will be that I'm home sick with a horrible cold, waiting it out to see if I'll need the antibiotics the doctor gave me a scrip for yesterday morning.


My inflamed sinuses are apparently blocking my brain from controlling my fingers . . . :I

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This one I do know is correct! Even if this is a bit nit-picky and something you already know, it's well worth defining the terms. Termination is either on of off, commonly set by a jumper or switch position. Whereas Active Termination is the function of additional electronics, usually implemented on the pass thru Connector/Adapter PCB of an external peripheral's enclosure. "Passive" termination would be the simple on-off toggling setup, like the jumper block on you adapter's header connections.


Unless, of course, common usage has blurred the distinction since that time when SCSI Interfaced Consumer Products and Wooly Mammoths roamed the Earth.


< . . . figures it's well past time to post a pic of such a critter in the Peripherals Forum & hopes WiKiPedia linkages will save him the bother . . . >


edit: drat! no automagical linkage . . . does the presence of text modifier code prevent this? :?:

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I remember having one of those adapters on a Seagate drive in my 6100, though I don't have the drive or adapter on me anymore. :(


I would try placing jumpers on ID0 and TPR. TPR tells me it might stand for "Termination Powered" or something-a-ruther. :p It can't hurt* to try anyway. ;)


* I reserve the right to be not responsible for any damage and/or personal injury that may or may not happen by listening to my "words of wisdom." :o)

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TPR is likely "Termination Power" the device will empower the bus in case voltage is weak.

This does NOT mean the bus is terminated. Termination has to be done seperately on the 50pin flat cable.

If you want to use ID0, no jumpers for SCSI ID have to be set.

If you need software for initializing your third party drive, you might try Lido:


Let us know how it goes, many of us will have to aquire old SCA server drives, as SCSI-1 50pin drives are becoming rare.


Edit: oops, just realized ojfd made things clear already.

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It looks like the one I have has "passive" termination. So I'll have to find a way to terminate it...

How do you know that it has "passive" termination? Does it have several terminator resistor blocks like that black SIL package at position RN1 in the picture?


Yours look to me more like this one (no terminator resistors)


The more I think about it, the more it looks that your problem might be even bigger. What 80-pin SCA drive is it that you have? Wide or Narrow? What's the model number? If it's Wide, then you have to terminate remaining 9 signal lines on the drive as well to allow it to run on Narrow bus. In fact, that SCA-TERM adapter in top picture does just that. There's a chance that your drive still might work without terminating those extra 9 lines, but it also might not. It depends on a lot of circumstances. Correct way to do it would be to terminate them. Using SCA drives on Narrow bus is tricky, better to stay away from them, if you're not a SCSI expert.

Check the links I provided in my post above.

More info also at: http://tinyurl.com/bsklufj

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This is a great start on a SCSI Voodoo HowTo for a sticky post in the Peripherals forum. As has been mentioned, we're all going to wind up using obsolescent server drives until somebody here decides to compete with Acard for the IDE <-> SCSI Adapter market.

Keep the informed and expert information rolling in here folks . . . :approve:

. . . I'm crawling back into bed for a while . . . xx(

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Follow up.

What I did, when I needed to put modern UW SCA drive on narrow bus was:


1. Installed this type of Narrow to Wide adapter directly on motherboard


2. Installed this type of SCA to UW adapter on the drive.


3. Replaced Narrow cabling with Ultra Wide one and used cable that had UW terminator at one end.

In that way, Ultra Wide drive had all signal lines properly terminated.



If the cable is too long / has too many connectors, it couldt be cut off near the last connector with very sharp knife

Flat, Ultra 2 cables (yellow) work best with older SCSI chips, I had problems with Ultra 160/320 twisted pair LWD terminated cables on some occasions. Don't ask me why, I don't know. (Impedance? Different termination circuitry?)

Edited by Guest
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How much length do the twists in a modern cable add to the actual length of wire that the older chipset's cable drivers are forced to handle in that scenario? :?:

Just though I'd ask . . . ISTR reading that too many adapters/connections could cause capacitance to rear its ugly head . . . but I've already been wrong once in this thread.

Apparently My Mileage Does Vary . . . |)


edit: does anybody have linkage to a well known, reputable, relatively affordable source for new, high quality internal SCSI cables and adapters?

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@ojfd: Huh, that's almost how I have my 4GB Compaq 68-pin SCSI drive set up in my 6100. :) I used one of those 68-pin to 50-pin adapters on the motherboard, a 68-pin cable, and another 68-pin to 50-pin adapter for the CD Rom Drive.


@24bit: Yeah, I realized that the Seagate I used was a 68-pin, not 80. So... I'll leave the SCSI advise to all you "experts." ;)

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edit: does anybody have linkage to a well known, reputable, relatively affordable source for new, high quality internal SCSI cables and adapters?

See links I provided in my posts :-)

Feel free to delete this post afterwards.



edit by jt: Thanks for the face-save offer there, ojfd!

But, nah! Let this stand as an object lesson for other -lazy-- . . . erm . . . casual . . . readers of informative threads like this! :o)


http://tinyurl.com/bsklufj = source posted above :I



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I only saw one more or less affordable 73GB new IBM drive here for EUR 63.- plus costs for an adapter.

Who would need 73 GB for a 68k Mac? Maybe the Amiga SCSI-1 to CF are the way to go rather.


powerpup, I hope I didnt hurt anybodies feelings, I´m by far no expert with SCSI HBA.

The few experts I knew, sadly moved to cemetary many years ago. The SCA would be trial and error for me.

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Still no luck with the drive, I noticed it is causing my Mac SE/30 screen to have some wavy-ness that travels from the bottom of the screen up. I think it much have some interference with the power supply. Went to my 250mb Apple drive for now, going to have to revisit the scsi drive for another project. :-/

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I am dealing with the same issue on a SCA drive connected to a 50-pin cable with a 50-pin to 80-pin drive adapter. I'm thinking one of these four ways should be successful but .. which one? The SCA drive I'm using (and most - all? - SCA drives) provides no termination so I'm going to have to have a terminator on the cable. Do I ...


1. get a 50-pin inline terminator to go between the 50-pin cable and the adapter (or logic board).


2. get an 80-pin inline terminator to go between the adapter and the SCA drive.


3. get a 50-pin to 80-pin adapter to go between the logic board and an 80-pin cable plus an inline 80-pin terminator to the drive.


4. get a 50-pin to 80-pin adapter to go between the logic board and a multi-connection 80-pin cable plus a terminator for the third cable connection (the one after the logic board and the drive).


5. Get a different 50-pin to 80-pin adapter that has termination onboard.

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