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Mac SEs won't boot with external SCSI attached

Tom2112

Well-known member
I recently acquired a number of classic compact Macs, including a couple Mac SE's. As I was going through the process of doing initial function checks on them - to determine which ones worked, which didn't, and removing PRAM batteries - I found that the Mac SEs without harddrives would boot just fine as long as I did NOT have an external SCSI device connected to them. But when I booted them with my RaSCSI connected externally, they would start to boot then give a Sad Mac with a error code that would normally indicate memory issues. (0000 000E 0000 FFFF)

At first I thought it was an isolated issue, but after the second and third unit to do this, I had a trend. Then I started to think, maybe I'm doing something wrong. So I tried other external SCSI devices, inlcuding my MacSD and my SCSI2SD v6. I got the same problem. I started to think maybe it was because the internal SCSI bus wasn't terminated with a drive (as there's not even a SCSI cable plugged in internally for these). But that doesn't make sense, because without the external SCSI device, the Mac boots just fine. (I was using my FloppyEMU to boot them, because they didn't have an internal HDD.)

So I'm at a loss. I figured I'd ask the experts here. Any suggestions? What am I doing wrong?

Thanks in advance,
Tom
 

Tom2112

Well-known member
I did not. After disassembling/reassembling so many Macs yesterday, I didn't have the gumption to tear two more apart - one to get the cable and one to test). I did seven yesterday. LOL
 

ymk

Well-known member
It sounds more like the SE doesn't like the boot image than a problem with the SCSI bus.
 

Tom2112

Well-known member
YMK, I'd say that would be possible if I hadn't tried different SCSI devices. But even if the boot image was bad on all three devices, then why wouldn't it just give the no-boot-disk-found flashing-?-in-the-diskette prompt? Instead it gave a black screen with sad mac and the error code.
 

Tom2112

Well-known member
Side note: when I had the MacSD connected, I noticed that it behaved like it wasn't getting enough power. All the LEDs were lit, but they were dim. I didn't try it on all of the SEs. So that may have been unique to that specific unit. But the same error across them all? That's weird.
 

chillin

Well-known member
Another option to try is boot key combos:
Cmd-Option-P-R /zaps the PRAM
Cmd-Option-Shift-Delete /forces a boot from external drive
Cmd-Option-Shift-Delete-<SCSI ID#> /forces a boot from the specified SCSI ID
Option /allows boot volume selection
 

ymk

Well-known member
Are you using the same image on all of the SCSI adapters?

An image can be recognized by the Mac as bootable, and then result in a sad Mac once it runs into trouble.

You could try running a SCSI diagnostic tool from your FloppyEMU.

MacSD has a TRMPWR pad near the USB connector. It should measure ~4.4V against ground.
 

Tom2112

Well-known member
Unfortunately, I'm not using the same image on all my SCSI devices. The RaSCSI images and MacSD images don't seem to be compatible, and frankly, I don't remember which image was on the SCSI2SD. Though I can say that all of them would be setup for Mac SE, SE/30, or Classic 1. Likely System 7.1 or 7.5.5, but maybe as late as 7.6.1. The RaSCSI was set to boot from the Apple Legacy Recovery disk (I converted it to a bootable hard drive image rather than a CD image and added some tools like the patched drive setup utils and Lido). I know it worked on the other Mac SE's because I used it to wipe their HDD's and installed system 7.1 using it. But these SE's without HDD wouldn't boot from it.

I'll have to test it with the MacSD internally and check that voltage you mentioned. I suppose its possible that each of them has a weak power supply and isn't providing enough termination power.
 
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