Help ID this port?

[badCaps]

Picked up a 512k recently and saw this port on the back.  This is an add on SCSI port replacing the battery slot, right?  Curious if anyone can identify this hardware and who manufactured it.  Assuming it includes an associated controller card.  Port is metal, looks well made, and the hole is screwdriver access.  Found a few other similar products, but none have this style of scsi port that is protruding from the case.

Have not opened it up yet to check the board inside for markings.

Anyone recognize it?



Similar products:

Mac Snap

https://web.archive.org/web/20060517040357/http://www.vintagemacworld.com/macsnap.html

https://web.archive.org/web/20060622022158/http://www.vintagemacworld.com/macsnap/macsnap_rear.jpg

Mac Rescue:

 

[Trash80toHP_Mini]

Not a clue, but be careful when you take the bucket off. There's no telling how much or how little slack there will be for disconnecting the cable before tearing something asunder. Is that branding on the case? Outside of that it looks remarkably clean.

 

[Dog Cow]

Picked up a 512k recently and saw this port on the back.  This is an add on SCSI port replacing the battery slot, right?  Curious if anyone can identify this hardware and who manufactured it.

There were at least half a dozen vendors of add-on SCSI for Mac 512K in the mid-1980s. You'll have to open the case and see who made it. Most, or probably all, of these designs had their genesis from a Dr. Dobb's article.

Oh, and it doesn't really "replace" the battery slot, but grafts atop it. There could still be a battery back there, so you'll want to see about removing it if present.

 

[unity]

Also some of the battery holders were trimmed on one side to accommodate the cable. Just FYI if you ever replace the supply. If not trimmed the cable gets very pinched and the case does not close perfectly.

 

[badCaps]

Not a clue, but be careful when you take the bucket off. There's no telling how much or how little slack there will be for disconnecting the cable before tearing something asunder. Is that branding on the case? Outside of that it looks remarkably clean.

The writing on the back appears the be the last name and phone number of a prior owner engraved with one of those handheld electric engravers.  Otherwise, it does appear to be clean and in good external condition.

There were at least half a dozen vendors of add-on SCSI for Mac 512K in the mid-1980s. You'll have to open the case and see who made it. Most, or probably all, of these designs had their genesis from a Dr. Dobb's article.

Oh, and it doesn't really "replace" the battery slot, but grafts atop it. There could still be a battery back there, so you'll want to see about removing it if present.

Thanks for the history, I did find the dobb article and usenet discussion, cool read.  Also found this little summary that was helpful: https://macgui.com/usenet/?group=8&id=2072

Also some of the battery holders were trimmed on one side to accommodate the cable. Just FYI if you ever replace the supply. If not trimmed the cable gets very pinched and the case does not close perfectly.

Appreciate the tip, looks like my next step is (careful) disassembly to find the origins.

Now I'll just need to find a long screwdriver to get at those fasteners deep in the handle.

 

[Dog Cow]

Thanks for the history, I did find the dobb article and usenet discussion, cool read.  Also found this little summary that was helpful: https://macgui.com/usenet/?group=8&id=2072

Yeah, and I'm planning to build one too for my Mac 512K. I bought a NCR 5380 SCSI controller a couple months ago.

 

[badCaps]

Yeah, and I'm planning to build one too for my Mac 512K. I bought a NCR 5380 SCSI controller a couple months ago. 

Wow just realized that the link I posted is YOUR blog.  Came up in a search randomly and just now saw it in your sig.  Awesome resource!  I'll be sure to follow the SCSI project if you are posting on your blog or have a thread going here.

 

[Dog Cow]

 I'll be sure to follow the SCSI project if you are posting on your blog or have a thread going here.

Yes, it will be in the Mac 512K Blog.

 

[badCaps]

Finally decided to take another crack at this thing.  It's been 5 months since I opened it up but I wasn't able to find any manufacturer name or other markings without taking the board out.  However, the board would not slide out since the add on card was too tall and the surface mount components were hitting the chassis.  Had to bend the side of the metal out and pop the board out from the bottom.
 

Check out the board, a few cool things going on here:



It appears to have 2 separate upgrades.  First is the 2 Meg "Fat Mac" upgrade from Perspect Systems Inc. out of Venice, CA:



Not too much out there about this company, but did find this ad in MicroTimes from 1986:

https://archive.org/details/microtimesvolume00bamp_14/page/n21



The case also has a cooling fan added to the rear vents with power tapped from the analog board.  Not sure if this is separate or part of the Fat Mac upgrade.

Also found this reddit thread for someone else who apparently found one of these.

https://imgur.com/a/bemqL


Second is this SCSI board from Julian Systems Inc. 



This is my main focus at this point.  I unplugged the SCSI cable but didn't remember or document which way the cable was installed.  It has a red stripe on one side for pin 1 I'm guessing, but this SCSI board isn't keyed and I'm not sure how it goes back on.  I suppose I should look at the SCSI pinout, find a ground or something and follow a trace on the board.  Have to do some more research but not plugging it back in until I'm sure its right. 

@unity Yup, you were right, the battery area was shaved for the cable to go through.   But I reinstalled it, the cable got pinched a little.  Bummer.  It doesn't look bad but a simple continuity test should confirm it's ok.

Another shot of the board showing overlap between the ram board and SCSI.  While I was attempting to remove the board from the chassis, the ram board actually pressed down on the SCSI board and it unseated it from the rom socket below just enough where the Mac wouldn't boot, just showed checkerboard on the screen.  Re seated it and everything was ok but there was a moment when I got really disappointed, thought I killed it!



Here is the 2048K as she sits now.  Still got a lot of work to do, none of the drives eject, gotta figure out the SCSI cable, its a bit dirty and there are some cool peripherals that came with it that I can't wait to try out.  But I think that will be a separate thread.



Just thought I would update this thread since I wasn't able to find much online about this setup.

And thanks to @Dog Cow for the work on his 512k site, lot of good info that helped me through this process.

https://macgui.com/news/article.php?t=470

https://macgui.com/news/article.php?t=471