Mystery port on Bondi iMac logic board

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cwsmith's picture
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Mystery port on Bondi iMac logic board

Okay, so I'm puttering around with some iMacs, planning to set up a print server on a slot-loading Strawberry.

The logic board on the Strawberry was dead, so I swapped the processor, VRAM, and drives into the logic board from a Bondi with a dead screen.

As I put the Bondi logic board into the Strawberry case, I noticed an extra port: next to the video connector is a small round port that looks remarkably like a serial (printer/modem) port of olde. Those of you who are old enough to remember beige Macs would recognize it: about 3/8 inch in diameter, with 9 pin holes.

Is this in fact a serial port? Would I be able to hook up my Personal LaserWriter NTR, or my QuickTake 150, or my old MIDI controller? If not, does anyone know what this port does?

I'd appreciate any ideas.

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another mysterious port

I dont know, but it does indeed sound like a serial port. On the other side of the board, if you look hard, you will see a small 2x(I dont know how many) pin port. guess what this is? a floppy connector!! that's right, apple left an old flppy connector on the motherboard, although no floppy drive came with it. if you can get one, find an old sony 1.44mb mechanisim, and plug er in. it will work, trust me.

good luck on finding out about that serial port.

-digital Wink

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The small round connector is

The small round connector is indeed a serial port. Its where the infrared module on the original bondi iMacs plugged in. I don't know if it can function as a serial port for anything else, though.

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Cool! Whether it will take m

Cool! Whether it will take my QuickTake or not, it's worth playing with (now that I know I won't blow anything up ...)

Thanks for the quick response, guys! Merry Christmas to all!

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Infrared Connector

That port connects to the built in infrared hardware that shipped with the bondi iMacs, but was deleted from the rev C on iMacs. I don't believe it's a functioning serial port, but it may be. (I seem to recall there being stickers inside the original bondi iMacs that said "This is not a serial port")

If you take a close look at the logic board, you'll find pin outs for an internal floppy drive (the controller is present on the logic board). Back when the bondi first came out, MacAddict had a feature on how to add a built in floppy to the bondi iMac. Also present are pinouts for ADB on the logic board (unsure if there is an adb controller onboard though). Other interesting things to look for - if you pull the logic board out of the tray it's in (since you spotted this port, it's still in the original bondi logic board/hard drive tray), on the underside, you'll see an expansion slot. This is the infamous mezzanine slot (also deleted from the rev C iMacs) that could be used for expansion cards, despite no official support for it from Apple. (I seem to recall a SCSI card) Fortunately, CPU cards from later models will work with the bondi logic board.

At the apple shop I used to work for in Florida, the owner somehow got his hands on a clear iMac prototype (all of the plastics were completely clear like glass, not ices like production and completely smooth - not textured like the shipping product) He also had an untextured bondi iMac as well. Both had the "Pending FCC approval" stickers on them. I don't know what became of them, a shame really.

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Re: Infrared Connector

iantm wrote:
That port connects to the built in infrared hardware that shipped with the bondi iMacs, but was deleted from the rev C on iMacs. I don't believe it's a functioning serial port, but it may be. (I seem to recall there being stickers inside the original bondi iMacs that said "This is not a serial port")

If you take a close look at the logic board, you'll find pin outs for an internal floppy drive (the controller is present on the logic board). Back when the bondi first came out, MacAddict had a feature on how to add a built in floppy to the bondi iMac. Also present are pinouts for ADB on the logic board (unsure if there is an adb controller onboard though). Other interesting things to look for - if you pull the logic board out of the tray it's in (since you spotted this port, it's still in the original bondi logic board/hard drive tray), on the underside, you'll see an expansion slot. This is the infamous mezzanine slot (also deleted from the rev C iMacs) that could be used for expansion cards, despite no official support for it from Apple. (I seem to recall a SCSI card) Fortunately, CPU cards from later models will work with the bondi logic board.

At the apple shop I used to work for in Florida, the owner somehow got his hands on a clear iMac prototype (all of the plastics were completely clear like glass, not ices like production and completely smooth - not textured like the shipping product) He also had an untextured bondi iMac as well. Both had the "Pending FCC approval" stickers on them. I don't know what became of them, a shame really.

woah, and didnt the original bondi's logic board use a standard (internal) VGA connector for the built in monitor? then on the later imacs, they used some sort of ribbon cable, and you couldnt use a VGa monitor until the DV modles came along.

am I correct?

-digital Wink

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Re: Infrared Connector

iamdigitalman wrote:
woah, and didnt the original bondi's logic board use a standard (internal) VGA connector for the built in monitor? then on the later imacs, they used some sort of ribbon cable, and you couldnt use a VGa monitor until the DV modles came along.

It wasn't a VGA connector, but an old-school Mac video connector (like what was on Apple's monitors, with two rows of pins). Also, that is *not* a serial port...it says so on the board right next to the port. It just happens to use the same connector.

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Re: another mysterious port

iamdigitalman wrote:
...a floppy connector!! that's right, apple left an old flppy connector on the motherboard, although no floppy drive came with it. if you can get one, find an old sony 1.44mb mechanisim, and plug er in. it will work, trust me...

Caveat: This is true ONLY if you are running OS 8.5.1 or earlier. As soon as you drop 8.6 on, the port is turned off. I have spent months fiddling around with the system folder and ResEdit to no avail.

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Re: Infrared Connector

iantm wrote:
...This is the infamous mezzanine slot (also deleted from the rev C iMacs) that could be used for expansion cards, despite no official support for it from Apple. (I seem to recall a SCSI card) Fortunately, CPU cards from later models will work with the bondi logic board...

...and AppleFritter is the only place on the web where you can easily find the original iMac's Mezzanine slot pinouts. (Or at least most of them).

The connector was removed from the C and D models, but the spots on the mobo were still there (as I recall).

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Serial

You could always add a Stealthport for serial. I think Griffin make/made one as well. They use the modem slot instead of the IR port.

I do seem to recall some hack that uses the IR port and the stealthport drivers to get serial. Maybe the pinouts are different or something. Google is your friend.

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Re: Infrared Connector

Dr. Webster wrote:
Also, that is *not* a serial port...it says so on the board right next to the port. It just happens to use the same connector.

Technically it *is* a serial port. The Griffin iPort:

http://www.macsonly.com/iport.html

piggybacked off the wiring to it to provide a good old-fashioned Localtalk serial port.

(The motherboard chipset in the iMac provides two serial ports. It's the same as in the Beige G3, after all. One comes out on the modem port, the other drove the infrared on the Rev A&B models.)

As to whether you can just plug stuff into it and use it as one, despite what the sticker says, well... I could *almost* swear that I've seen a web page where someone tried it and it did indeed work, but if you fry your machine trying it yourself it's not my fault. My Google-karma is weak tonight, so I can't find the page I may of hallucinated. Protocol-wise it *is* a standard mac serial port, but the pinout, voltage levels, and god knows what else might not be to spec.

--Peace

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Re: Infrared Connector

Thats what I was saying. It is a serial port, but I don't know if it might need modification to function as a standard Mac serial port.

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Re: Infrared Connector

themike wrote:
Thats what I was saying. It is a serial port, but I don't know if it might need modification to function as a standard Mac serial port.

Yeah. I was just showing the "proof". (I.E., the iPort.)

I'd be willing to try just plugging something into it and seeing if it's a normal serial port, honestly, since I'm just not that attached to my iMac and I have a spare motherboard, but:

A: I have no localtalk cables, so networking to my only other serial-equipped Mac, a Quadra, is sort of out.

B: I have no Mac serial devices.

C: My iMac doesn't have "classic" MacOS on it. I guess in theory I could test it out under OS X if I had a null modem cable, but... eh.

--Peace

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sigh...

...I have a Bondi, running Classic (albeit 9), more serial cables than common sense, and a Newton MP.

If I find time in the coming weeks, I will crack it open and try it out with NCU.

Given that I am ofetn out of town and away fro the machine, this may take me until mid January, btu I will add it to my list of things to get a round toit.

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Re: Infrared Connector

iamdigitalman wrote:

It wasn't a VGA connector, but an old-school Mac video connector (like what was on Apple's monitors, with two rows of pins). Also, that is *not* a serial port...it says so on the board right next to the port. It just happens to use the same connector.

Upon closer examination, I do see the words "no serial port" next to the mystery port, but I also see "no ext mon" next to the monitor port. Now, I know for a fact that this port will run an Apple monitor (with the 15-pin connector) -- I've done it myself to back up data from an iMac whose video is dead -- so "no ext mon" is bogus. Is "no serial port" bogus as well?

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Re: Infrared Connector

iantm wrote:
... pinouts for ADB on the logic board (unsure if there is an adb controller onboard though)...

I remember seeing a website where they added the ADB port to a Bondi iMac, can't remember if they had to add any other componenes though

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