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Plus with weird port on the back

fragmax

Active member
Hello, I may have bought this on ebay just to find out what this port is. Any guesses before it shows up?

1678510307518.png
 

3lectr1cPPC

Well-known member
That’s a head scratcher. Not much you can do with 2 pins. Something power related? I’ll be curious on what it turns out to be, so keep us updated! I’d guess an anti theft thing of some kind, but the plus has a slot in the back for that so it wouldn’t make any sense…
 

Paralel

Well-known member
I've honestly never seen a plug like that associated with any Mac or PC. I can't imagine what it actually does.
 

chiptripper

Well-known member
Saw that listing and wondered about it myself. And the markings. "CC" and... maybe the symbol is for AC power? Hmm.
 

fragmax

Active member
That’s a head scratcher. Not much you can do with 2 pins. Something power related? I’ll be curious on what it turns out to be, so keep us updated! I’d guess an anti theft thing of some kind, but the plus has a slot in the back for that so it wouldn’t make any sense…
With my luck it will be an anti theft thing. :)
 

warmech

Well-known member
@jzmacdaddy is it just a direct connection to the TTL signal off the LB, or does it pass through additional circuitry to shore it up to composite (NTSC, I presume) video requirements?
 

fragmax

Active member
It’s a composite video port with a weird connector. I have one exactly like it.
Thanks for the info. Have you ever used the video out? How does it work? UM computer Center was written on the side but someone used black marker to cover it up. If I look hard I can now make it out in the picture I have. I just checked the listing and the seller has listed another one with a external floppy attached to the side, mine doesn't have that and the writing isn't backed out and clearly says UM Comp Center. It also has the port. Can't wait to open her up and look inside.
 

Skate323k137

Well-known member
Is UM the University of Michigan?
I can't rule it out, since we had tons of these in our educational system, but I haven't seen UofM (Michigan) stylized that way in all my years of growing up/living in Michigan. My SE which came from a U of M prof wasn't engraved, but of course I'm sure professor machines versus computer center computers would have been treated differently.
 

fragmax

Active member
UPDATE- Computer arrived today and the mystery port goes to nothing. It must be some type of security device. Sadly the computer was not in great condition after its trip. Logic board works with no sound (even though they said it had sound) and the screen was an obvious broken screen taken from another working computer and put into this one. I guess I got my $59 bucks worth?? Thanks for everyone's feedback.
 

3lectr1cPPC

Well-known member
If it didn’t arrive as described, I’d try to get your money back immediately, especially if they put a known dud screen in there without mentioning it. $60 could buy you a working system only a few years ago.
 

JC8080

Well-known member
There is currently another one on eBay with clear U of M markings, as well as an external floppy attached to the side of the case:

I'm not sure if I'm allowed to put an ebay link in here, but this search term will pull it up: Vintage Apple Macintosh Plus Computer and Floppy Drive For Parts or Repair
 
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