SCSI Help

[adbower]

I'm installing a few SCSI components and want to make sure I do things right...

I have the following...

- Adaptec 2940UW controller
- Plextor PX-R412C int CD-R
- Plextor PX-40TW int CD-ROM
- Iomega SCSI ext Zip

So I have the zip connected externally, only thing connected. UW CD-ROM on the 68-pin ribbon. Should it be on the very last (end of the cable) connector? Does position matter? Do I need a terminator? Same with CD-R, except it's on the 50-pin ribbon.

Any info could be much apprecaited!

THanks!

 

[Zepper]

Most drives that would work on your adapter have termination built-in. There is usually a jumper to turn on/off. All of the drives should have termination set to ON. The zip and the burner will be on opposite ends of the narrow channel and the wide CD ROM drive will be on one end of the wide cable while the adapter will be the other end and will automatically turn on its own termination for that channel.
.bh.

 

[rommel]

yeah but if you use an external device the host adapter no longer acts to terminate the bus....well cuz if it did you couldnt use your external device...anyway..terminate the devices on each end of the chain...visualize the adapter as now in the chain along the middle or whateva...make sense?

 

[adbower]

Thanks for the help!

One question though... does position on the cable matter? Meaning do the devices need to be on the connector at the end of the ribbon?

Thanks again!

 

[SCSIRAID]

Now if I understand your config... you are using all three of the 2940UW's connectors... external, internal 68 and internal 50. This is an INVALID configuration. This creates a 'star' configuration instead of a 'bus' config. It may work but it is wrong. It will also have three terminations instead of the required two. You may only use TWO of the connectors.

Adaptec install guide

See page 5....

As to cable position... if the device attached has termination enabled then it must be at the physical end of the cable per the SCSI Spec

 

[adbower]

Damn, that's the problem. My cd-rom recently broke and I bought thought I'd go with the UltraWide instead of the regular ultra reader. Guess I should send it back and get the 50-pin version. I don't think there are any ultra-wide burners...

OH well..

Thanks for the help everyone!

 

[Mikendi]

You can get a 68 > 50pin adapter on eBay for a few bucks, or get an internal Zip drive, however they never made an iternal SCSI flavored Zip 250. If you got a card with your Zip you can have more than one host controller - both will share ID #7. If you put two, or more devices on the same chain only terminate the last device, or it won't work either. Here is a link to my favorite SCSI site: SCSI Nirvana Good luck with your project

 

[SCSIRAID]

There is one other option instead of sending back the wide CD. You can get a 68 to 50 converter to adapt the 50 pin device to the 68 pin cable. Just make sure it is NOT the device at the end of the cable and that termination is set off. It wouldnt hurt to also set "Disable Wide Negotiation" in SCSI setup for that id number.

 

[Zepper]

Yes, you should have a drive and/or termination on the end of each cable. There is a cable or adapter you can get at www.hypermicro.com and elsewhere that will extend a narrow or wide channel to a slot cover plate so that you can use the setup you have. Just instead of hooking the external drive to the adapter connector, just hook it to the cable adapter. With that, you just enable termination on the last drive on the cable.
...bh.

 

[ChuckWits]

I'm using an Adaptec AHA-2940UW card and can't get my computer to POST when the card is in a slot. No problems booting, etc. without the card installed in a slot.

Using Windows XP Home
Epox 8KHA+
Athlon XP 1800+

Anyone have any suggestions? This SCSI card is supposed to be compatible with XP according to Adaptec and MS.

TIA

 

[SCSIRAID]

If the system wont even POST with the card installed then the card is probably bad. Does the system power up at all? Fans? Video out of standby? The card could be tripping the power supply or hanging up the PCI bus.

 

[ChuckWits]

The system powers up and everything appears normal until just before it lists the pci assignments. It recognizes the memory and CD-RW, but during normal boot up the next screen would be when IRQ's are assigned, and the system hangs with the screen blank and a cursor in the upper left corner of the screen. I'll try changing pci slots to see if that makes a difference; if it doesn't, I'm afraid I'm at a loss as to what to try next.

 

[ChuckWits]

I just tried the card in PCI slots 2, 3, 4, and 5, with the same result. Due to the layout of the board, the card won't fit in slot 1 or 6.

Do I need a newer card? I'd hate to spend a bunch more money for a newer one, because all I want it to do is control the one DVD drive I have; everything else is ATAPI or IDE.

 

[ChuckWits]

Well, I just pulled an old Adaptec AHA-2940AU card from my other pc and it works fine. Booted right up, windows recognized the card, and the DVD works as it should.

I checked the Windows hardware compatibility site, and the AHA-2940UW is listed as "Compatible with Windows XP", so maybe it is a bum card. I guess I need to find out what kind of return policies Global Micro has

 

[Magicthyse]

My 2c adbower...

Devices on the UW external connector are treated as 'slowest is set speed' i.e. If you have a SCSI SE Zip drive on the external connector, the entire UW chain becomes SE. Am I making sense? So effectively, you derive no benefit from the UW capability of the card.

All of this, and more, is very clearly indicated in the manuals. I'd suggest that you take one more look at the manuals available on the Adaptec website and re-examine your setup - it will be much more helpful than getting vague answers here. If it still doesn't work - come back and we can point you in the right direction.

If you do want to attach non-UW external devices, I'd suggest the purchase of part number 498413-00, an external SCSI SE connector cable. This is basically a long cable with several internal SE connectors ending in a backplace with an external SE connector.

 

[adbower]

Where can I find this part? So would this effectively put my external zip drive on my internal 8 bit scsi channel?

 

[Magicthyse]

Where can I find this part?

Surprisingly, Adaptec
If you contact their sales, I'm sure they can give you pointers - I've gotten some helpful replies from Adaptec Sales (albeit after about 5 days, but exactly the info I wanted)