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Macintosh SE SuperDrive Floppy and SCSI Issues

I recently purchased a Macintosh SE SuperDrive off eBay, i got it in the post a couple days ago, the floppy drive was bad and the heads were out of alignment on the Mini-scribe Hard Disk. I attempted to boot off my Macintosh IIci's Hard disk, and it would not make any attempt to access it. When i go to boot with a Floppy, it happy macs, then spits it back out, I am using the known good floppy drive out of my IIci, used that same drive to make the boot floppy. Got it to boot once when i had the floppy drive outside the system, once i put the drive in the system, it would simply happy mac then spit the floppy back out. I have tried every disk i own, i even checked them for errors, i only used the error free ones i had left. The board is clean, no corrosion of any kind. I checked the PSU voltages and they are all fine as well.

I honestly Don't know what else to do with this thing.

Any ideas?

 

Bolle

Well-known member
I am goingto throw in Bourns filters here. I have an SE board with the filter in the floppy chain blown and replaced by single resistors and it is showing similar errors. It starts ro read disks, sometimes it works for some time but mostly it just spits them out again after some initial tries to read data off it.

Replacing the filter will most likely solve your SCSI issues as well, as the real problem is the Mac getting stuck on garbage coming in from the SWIM which results in it not booting from either floppy or HDD.

 
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Turns out, my floppy drive failed, so thats a bust, that was my last one.

I figured out the issue with the SCSI bus (i think and hope) CR1 on the board was cracked and had resistance. I ordered a new 1N4001 diode off the ebays.

CR1_Cracked.JPG

 

techknight

Well-known member
thats becuase someone plugged something non-scsi in the scsi plug. Like maybe a parallel printer. 

it probably fried the SCSI IC as well. 

 
thats becuase someone plugged something non-scsi in the scsi plug. Like maybe a parallel printer. 

it probably fried the SCSI IC as well. 
Hopefully it didn't fry the IC, i really don't want to have to get another board. I guess i could solder on a new SCSI IC if i can get my hands on one if it comes down to it.

my floppy drive is also not functioning properly, i think the heads may be misaligned, but i may be wrong. Whenever i insert a system disk, it happy macs, then spits it back out. I watched your video on restoring a mac classic and u mentioned something about floppy head or motor alignment, cant remember though, would it be possible to save that drive?

 

techknight

Well-known member
2 things I would try is cleaning the heads, and then making sure the stepper motor isnt seized and actually can move. 

 
Update: With a bit of fiddling with the floppy drive, i have managed to get it back into fully working order. Not quite sure what i did, but whatever happened, i somehow managed to correct it.

SCSI controller is dead, replaced diode, and nothing, i ordered a new SCSI controller chip from ebay.

 
Alright everyone, i have replaced the SCSI controller and still nothing. The system will not boot off my Hard disk, or my SCSI zip drive with a disk that contains system 7.1 made with my Macintosh IIci. Both drives boot off the IIci, but the SE still makes no attempt to blink a light. all that happens is the 2 drives both behave like they are plugged in without their SCSI Cables. I can still use the system with the floppy drive, but i only have 1 good floppy left, so that makes thing tough. If anyone thinks this board is still worth fixing, please pitch some ideas and suggestions my way.

I cant afford to lose any more brain cells :-/

 
I think you are right, i really don't want to do anything more to that board. Since i have the Superdrive model SE, do i have to get an FDHD board or can i get a regular board and swap the roms and the floppy controller? The ROMs and the IWM chip are socketed on my board, not sure if that goes for all of them or not.

 

unity

Well-known member
You can just swap the ROMs, all boards are socketed. Apple even sold upgrade kits for 1.4MB drives that did not require a board swap. While there are many board revisions, the only one that concerns most is the RAM dip selection. On early boards, RAM was configured by clipping resistors. Later on Apple added little plastic sectors to go over posts. Like hard drive selectors.

 

techknight

Well-known member
The immediate question that pops to mind when you mentioned you changed the SCSI IC, is what damage if any had you caused during removal and replacement? I am not saying that you did anything, but I do know from experience if your not careful during extraction and replacement, you can pull up traces on the top/bottom, or even worse, pull out the entire via plating thus breaking top/inner/bottom layer connections. 

 
The SCSI chip was a bit difficult to get out, but i managed to get it out none the less, from what i saw when i inspected the pads and stuff, it looks like the chip came out pretty cleanly, i even made sure every joint flowed properly, i even went as far to go and touch them up a second time, so i am honestly confused here. As i mentioned above somewhere, i also replaced the 1N4001 diode that popped, i also made sure that was in the right way, is there a such thing as a wrong 5380 SCSI chip?

 

techknight

Well-known member
Hmm. 

That was my area of concern. there is absolutely no way there would be any other damage outside of the SCSI IC itself, unless damage occured during removal and replacement and its really easy to do if your not careful. ;)

I may have a lobo without the ROMs kicking around somewhere... I will look. 

 
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techknight

Well-known member
Just checked the two I have are battery damaged. So nada there. 

 
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Err, battery damage, i was fortunate that mine didn't leak, my battery was also socketed, so not sure if that made any difference. I dont think i can afford to get another board at this time unless someone wants to give me an offer, i am going to be getting a new MacBook Pro here soon so i am a bit tight on cash at this time.

 
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