Information on SCSI drive Quantum QA250

[meall]

Hi,

I have another external enclosure with a 40 Mb HD (Apple branded) from Quantum QA250 in it.

I'm unable to make it mount on my desktop. If connected directly internally to the motherboard SCSI, the drive is working. I also tried it plugged externally without the Internal drive installed, and it booted (while the system cannot load on my LC 475, it proved the enclosure is working too).

I saw many jumpers on the drive, but cannot figure out what they stand for. Search Google, but cannot find any relevant information. Anyone can give a hand on this?

I would like to use that one on my IIgs. 40 Mb sounds more than enough for this and could be just right. But if I cannot have it working properly on a Mac, I suspect it will proved difficult to install on a IIgs!

Thanks

 

[meall]

I may have realise that the enclosure SCSI ID selection is not working at all. So the drive is always at SCSI ID 0. I tried switching the selector elsewhere on the drive jumpers, no luck there either.

So, if at least I could get the jumper settings for SCSI ID (even if I had to fixed it for its life) that would be great. Internet in this case looks useless! And no real indication on the drive itself...

 

[tomlee59]

Look for a sequence of three (or four) jumpers with labels like A0 A1 A2. Those are the scsi address selection jumpers. The presence of a jumper is interpreted as a '1' and the absence of a jumper as a '0'. A2 is the most-significant bit. A '100' is therefore scsi address 4. Sometimes, the connector for the external scsi ID selector has been removed, so you have to set the ID by configuring jumpers on the drive itself.

Termination requires that something supply its power. The drive allows you to specify whether that power comes from the host computer, or from the local power supply within the external drive's enclosure. The corresponding jumper will be labeled either TE or TP (I don't remember which). Try putting a jumper on one or both. Permute until goodness occurs.

 

[meall]

Hi Tomlee,

You indication were more than useful. I found immediately the A0, A1 and A2 jumpers and put one in A2+A1, which gave me the ID 6 I wanted. I could have tried lot of time on this, as the SCSI IS selector on the case was connected to something at the back on the drive, while those Ax jumpers were on the middle of board of the drive. I do not know how this could have worked for the previous owner! Because of the position of the Ax jumpers, I could not installed the case ID selector on it, so it is fixed... Better than nothing!

As for the other jumper you're talking about, I did not found any clear reference to them. But the drive worked whit my IIgs and its SCSI zip drive (set to ID5).

 

[equill]

When Quantum was sufficient unto itself, as opposed to being a part of Seagate, it was mostly into SCSI drives. It certainly seemed to have Apple's ear, or attention, because Quantum drives are probably the commonest to be found in early Macs after the vogue for Conner and Rodime had passed.

Part of Quantum's self-sufficiency was that it offered fewer user-accessible means of configuring drives, and those that it offered were sheltered behind mnemonics that were not explained. Seagate and IBM offered no-nonsense Termination Enable (for on-board ICs to provide active bus termination). Admittedly, the Quantum drives in early Macs were usually the only as well as the physically last drive in a daisy-chain, and passive termination with in-line resistor packs was (barely) adequate. Thus TE is usually not offered on older Quantum drives.

Tomlee59 has described Quantum's A0,A1,A2 system for setting SCSI ID. Once learnt, always remembered, but other manufacturers make the positions clear with ID0,ID1,ID2. Some Quantum drives offer ParK, as in what one does with one's chewing gum overnight. Handy if you happen to have a spare jumper. Product Option was probably more illuminating when a user had opted for a product. And then there was Disable Write, where other makers used Write Protect. Now that Quantum has been reborn as a division of Seagate in the ATA Era, jumpering Quantum drives is no more different than is jumpering any of the other differing manufacturers' different systems.

de

 

[trag]

Hi Tomlee,
You indication were more than useful. I found immediately the A0, A1 and A2 jumpers and put one in A2+A1, which gave me the ID 6 I wanted. I could have tried lot of time on this, as the SCSI IS selector on the case was connected to something at the back on the drive, while those Ax jumpers were on the middle of board of the drive.

The A0 - A2 jumpers are sometimes reproduced in larger .1" spaced jumpers at the end of the drive. In other words, they are sometimes present in two locations.

So the connections to the jumpers on the end of the drive may have been on the right track. If it was not working, the problem was probably one of two:

1) They connected the SCSI ID Switch wires backwards. There's a common side and a select side (or pin) to the jumpers. If you put the common side of the switch on the select side of the jumpers and vice versa, the switch does not work. I think it selects 0 or 7, but my memory and reasoning facilities are hazy on that.

2) They connected the SCSI ID Switch wires to the wrong jumpers. There's not much you can do about this, unless you have a manual for the drive which will identify the correct jumpers for you.

My guess would be that they connected the switch wires to the correct jumpers but installed them backwards.

 

[meall]

The A0 - A2 jumpers are sometimes reproduced in larger .1" spaced jumpers at the end of the drive. In other words, they are sometimes present in two locations.

So the connections to the jumpers on the end of the drive may have been on the right track. If it was not working, the problem was probably one of two:

1) They connected the SCSI ID Switch wires backwards.

I tried every possible combinaison and it did not worked in either position. So, cannot say. Nice to know they are reproduced at the back, but I did not see the A0-1-2 letters there, anyway..

Thanks

 

[porter]

I do not know how this could have worked for the previous owner!

Perhaps they happily used it as ID=0.