[mamorim01]

I have been restoring an Ultra 1 Creator unit for some time, quite a few issues that needed addressing (NVRAM battery, damaged CD reader, etc), and I am still trying to find a workaround for one damaged part. The unit had problems accessing the SCSI bus, down to being unable to probe it from OBP. I traced the problem down to the backplane and, in particular, the piece of cable that connects it to the CD drive. It looked okay from afar, but it did not take long to figure out that the tiny wires were loose and, in some cases, crossed with each other. In essence, the cable was basically hanging from a few wires which were still attached. Detaching the cable (no other way around it as it was already half broken and beyond repair) seems to have cleared the SCSI bus error and I can now probe it and boot from either of the two SCA connectors.

Since I have both SCA connectors on the backplane occupied with hard drives, I would like to find a way to connect the CD drive and not lose that functionality. The system has two spare SBus connectors but I have not been able to find one suitable card that provides an internal SCSI connector. All of the cards I have seen around would provide an external SCSI connector, or an ethernet RJ45 port, or both.

Has anyone got any experience with this type of arrangement and/or would there be any other solution I am possibly missing?


Detail of backplane with damaged connector on top. The cable on the bottom drives the floppy drive.



Detail of damaged cable to CD drive.



Detail of SBus connectors and external expansion slots.



Cheers,

[dexter1]

What about termination? Does the cable with the 50 pin conenctor have a terminator?

I would go low key and solder a replacement connector on the board, but i guess the pin spacing will make finding a suitable connector difficult.

[mamorim01]

The CD drive was originally terminated with a jumper. I now have a jumper set in one of the hard drives so as to terminate the chain, otherwise the system would not boot. It works fine, only I no longer have a spare SCSI connector for the CD drive so it is disconnected.



I guess I could solder on the back of one of the 80 pin connectors on the backplane but I am not confident in the reliability in the long term. The top connector is definitely not a possibility, the spacing is indeed an issue, plus I am not sure it is in good shape to begin with.

The easiest way to go would be to find an SBus card which provided one or two internal SCSI 68 or 50 pins connectors so I could simply run the CD drive from there, but I have been unable to find one?

If it came to that I guess I could just pull one hard drive and find a way to connect the 50 pin CD drive from the SCA connector there through an adapter. It is doable, but I would lose one hard drive :-/