SCSI Zip External does not work

thought i would be up and running after getting this ZIP but MPC does not pick it up

i tested ZIP drive with S3000XL and it works fine, thats out of the question

set the ID to 5 on ZIP and termination ON, set the MPC to AUTO in ID and rescanned, nothing...

i read somewhere that if the SCSI fuse is blown it won't matter with ZIP as it terminates on the external ZIP drive

last thing i wanna do is open up the MPC but maybe its a loose wire.. any ideas appreciated

Thanks for your ideas on this!

Which connector are you plugging into on the rear of the Zip drive?

Have you tried going into the SCSI disk format screen, setting the SCSI ID to 5, and formatting the disk?

I don't think that Zips provide termination power to the SCSI bus.

If the SCSI fuse is blown, you might have to replace it, or add a SCSI device to your SCSI chain that does provide termination power.

SCSI termination power is on pin 25 of the DB25 SCSI connector. It is very easy for this power on pin 25 to touch a ground point when a SCSI cable is being inserted or removed with the power on, which blows the MPC SCSI termination power fuse.

SCSI devices should never be hot swapped, always turn off power to the MPC, and any attached SCSI devices, before changing SCSI cables around.

You "can" check for SCSI termination power on the external SCSI cable, but again, because pin 25 which carries the termination power is so close to the ground on the connector, it would be very easy to short the termination power to ground, if the SCSI termination power fuse is not actually blown, so be VERY careful.

The SCSI termination power circuit, which powers the internal active SCSI terminators inside the MPC, on the MPC SCSI/D IN PCB, as well as sending termination power out the external SCSI port, has a 5V input from the power supply.

This 5V input goes through the SCSI termination power fuse (F901) on the SCSI/D IN PCB, then through a diode, before going out the external SCSI port (and through a regulator to the internal SCSI terminator circuit). So if measuring voltage on pin 25 of the external SCSI port, you should only expect approx 4.3V, due to the voltage drop across the diode, mine measures approx 4.15V.

Hi Simon,

tried formatting directly by setting ID to 5, sas FF48 no scsi found.

Used the same cable as connecting to my S3000XL, which worked perfectly.. rear goes into one labelled ZIP and the end that is labelled ZIP, the other end goes into the MPC.

The Zip Disk has a Termination on/off switch, i set it to ON, I was assuming its terminating the chain?

when i change it to OFF its still error FF48 but error looks slightly different, also says FF48 101/00/00 instead of just FF48

Thanks for the hint, have not been disconnecting cables whilst MPC was on, can't vouch for previous owner..

Any tips appreciated, looks like I will have to get it services. its no good without ZIP or Compact Flash.. Thanks

Someone else might have some different ideas on how to get it going, but it sounds to me like you have everything connected and set right, so other than a different SCSI cable (which should be OK if it works on your S3000XL), I would be looking at whether it has blown the SCSI termination power fuse next.

Another possibility, before messing with changing the fuse out (needs to be desoldered, and a replacement soldered back in), might be that the internal 26 pin ribbon cable from the SCSI/D IN PCB to the SCSI JACK PCB, might not be connected properly. I think, from memory, that this 26 pin cable is permanently connected at one end, but is removable at the other, maybe it has come loose for some reason, might be worth checking if opening up the MPC.

e9000k wrote:The Zip Disk has a Termination on/off switch, i set it to ON, I was assuming its terminating the chain?

The SCSI bus needs to be terminated at both ends, both at the last external SCSI device, the Zip drive for example, and at the internal MPC SCSI/D IN PCB.

There are different types of SCSI termination circuits, active and passive, active requires power, passive does not. It is possible that the Zip SCSI termination circuit is passive, and might not require (or provide) termination power, or that it is active, but does not send SCSI termination power out to the SCSI bus.

I do not know what the termination switch on the Zip is doing, but it is not necessarily turning termination power to the SCSI bus on and off, it might only be turning the internal Zip termination circuit on and off, without providing termination power to the SCSI bus.

I would be surprised if the Zip did send out SCSI termination power as a default, as I think that it is usually provided by the host SCSI adapter (the MPC SCSI/D IN PCB), rather than the connected SCSI devices.

If the internal MPC SCSI termination power fuse is blown, and the Zip drive (or other SCSI device) is not providing termination power to the SCSI bus, then the internal MPC SCSI termination circuit can not work, and SCSI will not work, no matter what SCSI termination on the external device is doing.

I have about six zip drives and various samplers.
Some of the drives only work with certain samplers and not with others , though they all work with at least one sampler.
I can;t explain this but i think it's just the nature of the beast.
If your SCSI fuse turns out to be good, it may be worth trying a different drive or cable and see if that helps.

Back now.. ZIP is working again

The cable from the SCSI PCB to the other board was not sitting right, plugged it in right and it started working!

Thanks all for help.