Let's Play "Mac Plus Mystery Port"

[Mac128]

Anybody got a clue? Could it really make this nice Mac Plus worth US $139?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250202694198

 

[macclassic]

Can't guess but the seller certainly believes in pictures!

 

[TheNeil]

Hmm, strange - maybe a 9 pin serial port? Wonder if it's actually wired up to anything or whether it's just stuck/bolted onto the case. Be very interesting to crack open and see what's lurking inside

 

[tomlee59]

That could be for an external TTL monitor. Looks like a home-brew job, though. Very ugly!

 

[zydeco]

Looks like one of these:

http://www.hardwarebook.info/Monochrome_TTL_Video

 

[slomacuser]

http://ia300134.us.archive.org/2/items/DesktopP1986/DesktopP1986.thumbs/DesktopP1986_00113000.jpg?cnt=0

http://ia300134.us.archive.org/2/items/DesktopP1986/DesktopP1986.thumbs/DesktopP1986_00000016.jpg?cnt=0

http://ia300134.us.archive.org/2/items/DesktopP1986/DesktopP1986.thumbs/DesktopP1986_00103000.jpg?cnt=0

http://www.archive.org/movies/thumbnails.php?identifier=DesktopP1986

http://www.archive.org/details/DesktopP1986

 

[equill]

The choice of a DB-9 connection may indeed indicate an external video hack. The security lug opening is logical enough as an exit for a ribbon cable, assuming that individual cables weren't used. The installation is neat, even if it is also ugly, as tomlee59 points out. However, the use of a DB-9 may reflect no more than having had male and female connectors in the parts drawer. What if someone lashed-up an electronic security system in place of the purely physical one that was originally envisaged in the design?

Only flipping off the bucket and looking inside is going to settle the matter, but TTL monochrome video out or fancy security system alike are not gzackly $100 premium attributes for a Plus.

de

 

[Anonymous Freak]

heh. I like "with a mysterious unknown BUT VERY RARE UPGRADE". Uh, if it's unknown, how do you know it's very rare?

 

[Quadraman]

This seller has had that Mac up for sale a few times before. The market obviously doesn't see it as being worth the price.

 

[TheNeil]

Or maybe the 'mystery element' is too much for them

 

[Mac128]

If slomacuser is correct and this is a Radius screen spanning external monitor output port as demonstrated in that video, then this indeed may be a rare and therefore suitably priced Plus. As far as I knew, screen spanning was not possible until the SE & II. I knew the early Macs could easily have external video, but that it was usually just for mirroring what was on the built-in monitor.

Thanks for that video. That's amazing technology for 1986. The guy on eBay would do well to try and figure out what he's got rather than re-listing it until his eBay listing fees negate any of the inflated profit he hopes to earn. Then again maybe he's got nothing and knows it and also knows a fool and his money are often quickly parted on eBay.

 

[trag]

I'm pretty sure that's a Lapis external video upgrade. I can't remember the name of the specific product, but if I remember to, I'll check the two boxed, never used ones I have in my closet when I get home... I'm pretty sure that the external video connector looks just like that. However, there were multiple versions with different video connectors.

Hmmm. Lapis something Display. Or Lapis Display Something.

The thing is based on a Xilinx FPGA and Lapis touted that they could update and modify the functionality of the card by issuing a bit of software to put on the computer, which would be consistent with changing the configuration file for the FPGA.

Jeff

 

[Scott Baret]

I have a Classic with a video out that used to go to an overhead projector device at a school. It actually has a connector identical to a CGA monitor for a PC yet the CGA I plugged into it didn't work.

 

[equill]

That sounds as if it could have been a Computer Accessories Corporation Mac Data Display A342, a 512x342 external LCD device (circa 1987) for the Macintosh to SE and any transmissive overhead projector.

Before I was reminded by Scott, I had forgotten that that device uses a DB-9 out, designed to pass through the security slot. However, the connector has no particular virtue in itself if the separately-powered (9VDC) display module (which contains all of the electronics to process the signal 'picked off' from the power/sweep board to logic board loom) is not included in the deal.

de

 

[kastegir]

I believe I have a plus in my garage with that connector on it. I bought a box of 3 of them from a university and haven't gotten around to cracking one open.

I'll try to have a look later this week.

 

[kastegir]

OK, I opened one up and it is, in fact, a TTL video expansion by Lapis Technologies. It has a daughterboard mounted on the logic board with the video out connection wired to tbe back of the case. There is also a clip onto one of the resistors on the logic board, but i didn't pull the motherboard to check it out.

 

[Bunsen]

Computer Accessories Corporation Mac Data Display A342, a 512x342 external LCD device/ the separate/ display module (which contains all of the electronics to process the signal

... is sitting about 15 feet away from me
Hence, kastegir, if you find the time, I would love to know more about this daughterboard.

 

[Bunsen]

I'm exceedingly keen to try and get the LCD panel I have here working with some compact Mac or other. If any of you who have replied above saying you have a compact with this type of adapter are interested in helping out, I'd like check out the feasibility of cloning one. Any information you can provide would be greatly appreciated.

Equill, do you have such a device as you describe in your possession, or are you painting from memory?

Does this look familiar to anyone?

/edit/ Scratch that; I know what it is now, thanks to the immortal Jag. And hence am I somewhat tempted to purchase it.

 

[Charlieman]

Like you, Bunsen, I am very tempted. If anyone wishes to clone it, and has the necessary proven skills, I'll buy it for them in return for a clone. That is a serious offer.

BTW, I am pretty sure that the 128\512 and SE\SE\\30 adapters are the same -- just the power cables are different.