Strange SCSI behaviour - maybe missing terminator?!?

[JohnFante]

Is the cdrom a 68pin cdrom or are you trying to adopt a 50pin cdrom to a 68pin UWscsi chain?

It is a 50pin CD-ROM with a 68pin to 50pin converter. It is a Plextor PX.32TS. Se photo. Just to be clear. It has worked fine but has stopped working because I removed a HD, attached a terminator etc.

Have you went into the csppc early menu and checked the scsi setting? perhaps something is off? You might set everything to auto until you get up and running.

I have set everything to auto. No result

Maybe the cdrom drive is bad? 15-20 year old scsi drives do fail sometimes.

I have thought about that but since it has worked flawlessly until now combined with the fact that It worked very shortly during my "fideling" and the fact that I get the same error when I use a Plextor PX-W124TS CD-ROW dirve I would say that it is unlikely.

You could use a cd/dvd drive on the internal ide with no problems. it will be slow,but as you say, something is better than nothing. Be sure to set it as master if its the only ide device.

Great :-) I will dig one out and see what happends.

[JohnFante]

When a narrow device is connected somwhere in the middle you can simply use an ordinary adapter.

Only if you connect that device to an end and need it to provide termination (no cable terminator) then you need a half-terminating adapter to take care of the high byte.

I moved the CD-ROM to the middle of the chain and changed the ID's so that it is:

Active terminator
CSPPC
IBM ID0 - no term power
CD-ROM ID2 - no term power
Seagate ID5 - term power
Active terminator

Stil the same. :-(

Maybe my terminator is no good? It has no LED so I can not see if it has termination power. But when I remove it (and the CD-ROM) my system will not boot so it must be doing someting.

[JohnFante]

Just a quick thought after I browsed for help.

Do the HD's have to be set for single ended? There is a jumper on both that can force single ended. At the moment they are off.

The drives are a IBMDRHS-36D and a Seagate ST150176LW.

[JohnFante]

And you can't mix SE and LVD on the same bus. Back when SCSI was popular you'd get servers with an UWSCSI raid controller for the harddrives and another SCSI2 controller for running the optical drives.
 
If you've still not got it sorted and you want to have them on the same bus then you will need to read up alot more on SCSI and do some trial an error adding and removing devices.

My HD's kan do both SE and LVD.

I will se if forcing SE gives any result. If not then I will switch to a IDE CD-ROM and give  my SCSI-problem a rest and read up on SCSI.

I am a bit tired off moving drives and jumpers around .... :-)

[JohnFante]

Well changing the jumpers to force single ended did'nt make any difference.

I have now installed a old IDE CD-ROM and it works flawlessly in OS4.1. Worked out of the box.

Somewhere along my fideling my OS3.9 install broke. And since my OS3.9 boot disk was created with my SCSI CD-ROM I get an error when I try to use it. Any suggestions on how to change a Emergency boot floppy from SCSI CD to IDE CD?

And last but not least thank you very much for all your help. :-D

I will get back back if I - eventually - find a solution to my SCSI-problem.