ZuluSCSI 2 2040 Help w/ Mac Plus

[dv-]

So I have a Mac Plus which boots fine from a Floppy EMU. It makes some funny noises and I need to recap some stuff, but it boots and has 4MB of RAM.

I wanted to go the SCSI route with a ZuluSCSI though, so I got the Mini RP2040 (external SCSI device, DB25 port). I was able to hook it up to my G4 running OS9, format a 400MB disk partition, and install a universal system 7.1 installation.

So when the Plus powers up with the ZuluSCSI attached, it blinks a question mark for a second, and then the screen goes black. At the same time, the LED on the ZuluSCSI turns on solid for like 5 seconds and then turns off. Then... nothing happens. It just sits there.

I plugged it into an external USB power brick because I know the Plus doesn't offer active termination power, and I selected "MacPlus" mode in the .ini config file.

I've attached my log and ini file; anybody have any ideas?

 

[finkmac]

does your zulu disk show when you boot from a floppy image using your floppy emu?

 

[dv-]

does your zulu disk show when you boot from a floppy image using your floppy emu?

It won't boot with the Zulu attached at all. Just the same split second of question mark, then black screen.

Pressing the reset button goes straight to black screen as well. The status screen on the FloppyEMU never shows disk access either. (Normally it will show what track/position is being accessed as the computer chugs along.)

Unplug the Zulu and it works fine, though. If the Zulu is unpowered, it also boots from the floppy OK.

So I guess it's barfing when it tries to scan through the SCSI bus?

 

[ironborn65]

I would do a recap before any further test or reboot. I recommend it as a baseline with these machines before doing anything else

 

[Daniël]

I wouldn't be surprised if the ZuluSCSI ends up drawing more power than the FloppyEMU, and it might be just enough to drag down the voltage beyond what the Plus can cope with. Funny noises generally come from the analog board, which could be the cause for unstable voltages.

You can check the voltages at the floppy drive connector, if you have a multimeter with thin enough probes.
Connect ground to one of the DSub screw lugs

 

[cheesestraws]

The screen going black and the whole thing wedging does intuitively feel like power somehow, although given that you're running the ZuluSCSI off a power brick, I'm not sure how. Either way, though, it's worth verifying that your power rails are good and stable with the ZuluSCSI plugged in as a first step...

 

[cheesestraws]

oh, hang on:

format a 400MB disk partition

What did you format it with? What version of the disk driver is installed?

 

[dv-]

oh, hang on:



What did you format it with? What version of the disk driver is installed?

The HD SC Toolkit on the install disk for System 7.1. Although I ran the tool and the installer from my G4 running MacOS 9.2.2.

 

[dv-]

So looking at this page: https://console5.com/store/computer-cap-kits/mac-68k-cap-kits/mac-plus-cap-kits.html

I'm guessing I need the non-international Analog PCB kit at least. (I'm in the US and the computer is from here - I got it when I was ten.)

Should I get the Main PCB cap kit as well?

 

[Daniël]

I'm guessing I need the non-international Analog PCB kit at least. (I'm in the US and the computer is from here - I got it when I was ten.)

Correct, the international model is for 240V, so you'll want the non-international kit.

Should I get the Main PCB cap kit as well?

It's not as urgent, but given it's only $4 for the kit, and you're going to recap the analog board anyways, I'd do it.

 

[dv-]

Well, after a recap, I no longer get a black screen - now I get vertical lines. (I thought that meant a ROM problem?) And then the screens gets weirder from there.

I got a BlueSCSI and that works like a charm so I double-don't-know-what's-going-on. If it was just a matter of wanting it to work, that would be great, but I'd really like to know _why_ it doesn't work, yaknow?

While I was doing the recap, I checked and the ROM chips are rev3. AFAIK that's the latest version and has all the SCSI bus fixes. I also tried the sample zuluscsi.ini in the other thread. I'll probably try the diode mod for SCSI term power next.

Thanks again!

 

[dv-]

So I emailed the ZuluSCSI seller, (who responds to emails way too fast. I think they might not sleep?) and it turns out the Plus is very picky about what drivers you use to initialize the hard drive image. I just happened to be using a premade image on the BlueSCSI that was ok.

The default Apple drivers are a bad idea. Even booting and using the Plus to format the drive image, it would crash halfway through formatting using the Apple tools.

Worked with Silverlining though; works great now!