Strange SCSI behaviour - maybe missing terminator?!?

[danbeaver]

To Mechy

So the internal chip in the active terminator works without any electrical power like a resistor?  It attempts to normalize the bus signal with an un-powered circuit?  Then what is the termination power used for?

[Zac67]

All terminators require termpower, regardless of type. At least one device needs to supply TP.

[danbeaver]

Well that clears up the Active vs Passive question

[darksun9210]

how's you getting on dan? i shouldn't think you've fried the cyberstorm... maybe if you put just the two hard disks on the chain, physically either side of the cyberstorm, and set the drives to terminate, this should terminate the bus without the worry of narrow devices, or possibly dodgy terminators.
do they show in early startup?
once you have one or two devices showing, then add the rest one at a time...
i remember having devices on the bus for the sake of it. zip, jaz, RW MagnetoOptical, yadda yadda. do you really need a zip drive? and two hard disks? can you not consolidate?

just thinking "out loud" best of luck!

[JohnFante]

how's you getting on dan? i shouldn't think you've fried the cyberstorm... maybe if you put just the two hard disks on the chain, physically either side of the cyberstorm, and set the drives to terminate, this should terminate the bus without the worry of narrow devices, or possibly dodgy terminators.
do they show in early startup?
once you have one or two devices showing, then add the rest one at a time...
i remember having devices on the bus for the sake of it. zip, jaz, RW MagnetoOptical, yadda yadda. do you really need a zip drive? and two hard disks? can you not consolidate?

just thinking "out loud" best of luck!

Its not Dan's problem :-) as far as I know ....

Good to know that I "probably" havn't fried the Cyberstorm. I must admit I am rather concerned thou. I disassembled all the drives. Checked the SCSI-id's, the jumpers and the power cables (as good as I could) and put in the two HD's and the CD-rom and the terminator in the end.

Still nothing. The HD's dos'nt spin up anymore and the system goes to the floppy boot.

I will try with only one HD but to be honest I am not very optimistic. I think I need some physical assistance to sort this one out.

I will get back when I - hopefully - find the solution.

Thank you for all the help.

[JohnFante]

WOOOHOOOO!

Things are running again. :-D

When I removed the CD-ROM (Plextor PX-32TSi) so I only had the two HD's (Seagate and IBM) and a terminator at the end the HD's spinned up and I was able to boot my OS4.1 install.

And as far as I can feel the HD's works a little bit faster with the Quantum drive of the chain.

Now I only need to get the correct jumper settings for my CD-ROM drive to solve the conflict I have.

Anybody have any experience with how to correctly configure a Plextor PX-32TSi CD-ROM drive or a Plextor-W124TSi CD-RW drive?

Thank you in advance.

[Zac67]

Dunno about Plextor, but there's usually a TE jumper (for Terminator Enable) - remove. PE is Parity Enable (you'll want that on), TP Term Power (don't need it, remove). The ID must be unique, of course.

[danbeaver]

JF, I know you didn't ask, so take this as unsolicited info:  the Acard 7720UW (100 USD) will allow a wide-to-IDE conversion for a new DVD-RW drive at full 2012 speed on your CSPPC bus and white ones to match your Amiga are available.

[mechy]

WOOOHOOOO!

Things are running again. :-D

When I removed the CD-ROM (Plextor PX-32TSi) so I only had the two HD's (Seagate and IBM) and a terminator at the end the HD's spinned up and I was able to boot my OS4.1 install.

And as far as I can feel the HD's works a little bit faster with the Quantum drive of the chain.

Now I only need to get the correct jumper settings for my CD-ROM drive to solve the conflict I have.

Anybody have any experience with how to correctly configure a Plextor PX-32TSi CD-ROM drive or a Plextor-W124TSi CD-RW drive?

Thank you in advance.

Just set the jumpers so it is a device between 0-6 and does not conflict with another drives on the chain(remember each scsi drive has to be a diff. number). then set termination on or off depending where it is on the chain. generally i set the hard drive numbers lower and the cd after those. the jumper settings are usually on the back of the cover or label.
putting 50 pin narrow scsi drives on the ultrawide 68 pin chain will generally slow everything down.  Plextor did make 68Pin cdroms also.

mech

[darksun9210]

Heh, woops, sorry, my bad,
glad things are running again! i've not had good expiriences with 50 pin to 68 pin adapters, and an old friend had so many issues with 50 pin devices, he ended up getting an A4091 scsi card to run them.
at the time i had an A4kT, so could string them off the onboard scsi, and leave the fast hard disks to the PPC's scsi.

i know it doesn't help you much, but just an anecdote from my expirience.

on a side note, i was having massive issues with the scsi chain i had on my PPC1200. turned out it was the Plextor CD/RW had finaly given up the ghost. i thought they were indestructable. but it turns out that no matter what i did with the termination or IDs, everything was rosey once i took the plextor out of the loop. so i'm at a loss as to what's going on there. maybe something similar is/was happening to your setup?

[danbeaver]

Again, nothing in this post will solve your issue, but since the last "unit" on the bus/chain is designated by its ID number and the controller wants to know the last device and last unit number, I have always felt that it should be a drive where this is recorded in its RDB; so I use a HDD there and a CD earlier.

[mechy]

Again, nothing in this post will solve your issue, but since the last "unit" on the bus/chain is designated by its ID number and the controller wants to know the last device and last unit number, I have always felt that it should be a drive where this is recorded in its RDB; so I use a HDD there and a CD earlier.

Not sure what you mean here,but setting last unit i.e. in hdtoolbox is just to keep it from wasting time scanning past that ID - you can also set last LUN iirc. that value is written to the RDB.
Since scanning starts at ID 0 it makes sense to have the boot drive low as possible for quicker booting.
A narrow scsi controller actually does not care what the last number is and doesn't need to know..  if no last id is set,on narrow scsi it will scan 0-6 (controller usually 7) and on UWscsi supports 15 devices.

Now in scsi,termination wise the last drive doesn't care what number it is,its just the last drive physically on the last connector.(i know this has nothing to do with what you said above,just a FYI here).

Putting a cd early also slows things since cd's come on the bus slower than the average HD(not always-but in many cases..) In the reality of things this may not make enough difference to change it.

Some like to put the hd at ID 0 and the cdrom at ID5,i never really understood this,makes more sense to me to do ID0 for the hd and say ID1 for the cdrom if its the only other device.

Setting LASTID sometimes can be a pain,if you add a device past the last ID,and forget to edit the rbd to scan to the lastID,then you set there wondering why it doesnt see the drive you added.. lol.

Mech

[danbeaver]

It appears to me before booting the SCSI controller scans the entire bus querying each ID (and LUN) before it does any booting. Also whenever I change a device (CF Card added or removed at end of chain -- something I no longer do) when I go to HDToolBox or Media Toolbox I get a "need to update drive" request dealing with Last ID / LUN. From this I inferred that the controller wants to be able to write this info into the RDB or someplace on the drive; hence a CDROM would have no place to write this.

In addition how can an active terminator circuit "actively dampen" a signal without a power supply?  A resistor uses the power of the signal itself to reduce that signals amount of voltage, but a circuit that attends to do a proper reduction of a signal voltage should itself be powered. If so, how can it do that without, lets say for the sake of argument, without termination power. If it does so with another power source, what is then the termination power used for?  I'm not an electrical engineer and I think in terms of digital rather than analogue, but a simple transistor setup to dampen an excessive signal voltage still needs a separate power supply, or is there another way around this?

[mechy]

It appears to me before booting the SCSI controller scans the entire bus querying each ID (and LUN) before it does any booting. Also whenever I change a device (CF Card added or removed at end of chain -- something I no longer do) when I go to HDToolBox or Media Toolbox I get a "need to update drive" request dealing with Last ID / LUN. From this I inferred that the controller wants to be able to write this info into the RDB or someplace on the drive; hence a CDROM would have no place to write this

Dan,
It will write the last id to the boot drives RDB to what the last drive now is in this case.It would not try to write it to a cdrom of course since its a read only removable as far as i know.

mech

[danbeaver]

Yes, that was my point; it can't write last anything to a CDROM so it just keeps checking all the IDs and LUNs.

Any help with the rest of the post on how active termination circuits work without power?

[mechy]

Yes, that was my point; it can't write last anything to a CDROM so it just keeps checking all the IDs and LUNs.

Any help with the rest of the post on how active termination circuits work without power?

i guess i misunderstood what you were saying about the cdrom.

on the terminators, Someone else answered that for you earlier(Zac iirc), but the answer is they dont,you always need term power or terminators do not work

most active terminators use a custom chip to keep bus levels right,it of course also needs power.


Mike