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SCSI2SD "Load Failed"

bigmessowires

Well-known member
I'm trying to configure a hand-built SCSI2SD v3.0 board that I acquired in a trade some time ago, but never used before today. I’m having some trouble getting it going, and I’m not sure if I should be troubleshooting the board, or if I just don’t understand what I’m doing - which is likely, since I’ve never used a SCSI2SD before.

When I plug it into my Windows machine, it makes the USB ding-dong sound, which is good. And when I run scsi2sd-util, it sees the board. It told me I needed to update firmware, which I did (to version 4.7), and that all seems fine. The status line at the bottom of the GUI says "SCSI2SD Ready, firmware version 4.7.1". But whenever I try to load or save settings to the device, it says “load failed” or “save failed”. The scsi2sd-util GUI also often becomes unresponsive for 5-10 seconds at a time while I’m clicking on things.

I also tried connecting to a Macbook Air running the OSX version of scsi2sd-util, and I got the same "load failed" error, and the same unresponsive UI.

Ideas?

 
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bigmessowires

Well-known member
Do I need to have the SCSI2SD powered from the 4-pin molex connector in order to use scsi2sd-util? I've only got the USB cable connected and nothing else. 

I can't seem to find any actual documentation for SCSI2SD. The user manual is just a few brief paragraphs that don't explain much of anything. Is there other documentation I'm missing, or are users just left on their own?

 

saybur

Well-known member
Do I need to have the SCSI2SD powered from the 4-pin molex connector in order to use scsi2sd-util? I've only got the USB cable connected and nothing else. 

I can't seem to find any actual documentation for SCSI2SD. The user manual is just a few brief paragraphs that don't explain much of anything. Is there other documentation I'm missing, or are users just left on their own?
Mine run fine with just the USB cable, but I have had problems before when a SD card is not present - do you have one installed?  Also, what platform are you running it on?

In the past, I've had to diagnose problems using the scsi2sd-monitor utility, which has no documentation that I was ever able to locate.  For that one, investigating the source was required (and adding some debugging statements).

 

bigmessowires

Well-known member
Mine run fine with just the USB cable, but I have had problems before when a SD card is not present - do you have one installed?  Also, what platform are you running it on?
Yes there is an SD card present. I tried scsi2sd-util on both Windows and Mac with the same results. I suspect there's something wrong with the USB interface on the board.

The good news is it's working now, mostly. I was never able to get scsi2sd-util to change and save the settings, but I got the SCSI emulation to work with the default settings (one 2GB hard disk at SCSI address 0) on a Mac IIsi. It's too bad I apparently can't change the settings, but I can live with the defaults.

How is termination power supposed to work for internal SCSI connections on vintage Macs? From what I read here about pre-v5.0 boards, most SCSI controllers provide term power on the internal 50-pin SCSI connector, so a separate source of term power isn't needed. But I couldn't get it to work in the Mac IIsi until I installed the J3 TERMPWR jumper, and then it immediately started working. Is that normal, or maybe a symptom of some problem?

 

saybur

Well-known member
I believe internal SCSI on (all?) non-portable Macs provides TERMPWR, fused on the logic board.  The schematic for V4 of the SCSI2SD has J3 connect +5V through a diode right to the SCSI TERMPWR line, which sources power to device terminators if the main board fuse is open.  I don't have the V3 schematic, but I imagine it's set up the same, it's in line with the way the SCSI spec talks about it.

Maybe check if the IIsi board has an open fuse?  Or check the input voltage on U2 (right leg, the one with the cap) without J3 shorted, might be that the line is sagging below the ~1.1V headroom on the regulator?

 
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