Apple’s Proprietary 300-pin Connector Is Not Proprietary At All

[Nullcaller]

Ladies and gentlemen, we got 'em. Kind of, sort of... Let me explain.

In every topic I've come across, in every teardown article and every video, the 300-pin connector Apple used for the CPUs on the G5s and G4s (except for the 'Yikes!' ones, I guess), as well as for connecting all the different boards in the 2013 Mac Pro (affectionately known as the 'trash can'), is simply called 'proprietary 300-pin connector', thus waving away any questions for what it actually is, how it's called, and whether or not you can order one: Apple designed it, Apple owns it, and Apple will never sell it to you.

The 300-pin connector on the Power Mac G4 Quicksilver (courtesy of iFixit and Chris Green, under CC BY-NC-SA 3.0)

The Late 2005 Power Mac G5 processor daughter card, featuring the 300-pin connector (my own photos, CC-BY 4.0 unless forum rules state otherwise)

The 2013 Mac Pro halfway through the disassembly process and the bottom connection board, featuring three 300-pin connectors (courtesy of iFixit and Andrew Optimus Goldheart, under CC BY-NC-SA 3.0)

This is, in fact, not true. The pinout is probably different on virtually every device model, that's for certain. But the connector itself is an off-the-shelf one, and its name is 'Amphenol MEG-Array Connector'.

I've had a hunch it was not a proprietary Apple-designed connector for a while. After all, Sonnet somehow had access to it. I doubted that it was Apple-sanctioned, and I also doubted they went to the trouble of copying it for a couple of CPU boards. I've been trying to find what it was for a while, but unfortunately, it's extremely difficult to find any connector or any SMT component if you don't know what exactly you are looking for. The right keywords for the type of connectors I was looking, in the end, were 'SMT high density connectors', which led me to 'SMT high density array connectors', and searching for 'array connector' on AliExpress, I found the '84740-102LF' connector, which looked suspiciously like Apple's 300-pin connector, except it had 400 pins.

P.S. This post is brought to you by my ongoing investigation into whether or not it is feasible to convert a Late 2005 Power Mac G5 DC board into a Quad board by soldering on an additional socket. Please, do chime in if you have something interesting to tell on that subject!

 

[Nullcaller]

The MEG-Array connectors come in different variations based on pin count and mated heights.

The mated height on the Late 2005 Power Mac G5 seems to be 8 mm. I've measure the top of the daughter card to board distance to be 9.87 mm, and the daughter card thickness to be 1.83 mm, so the mated height seems to be 8.04 mm, give or take 0.2 mm. The only height that fits out of the available ones (4, 5.5, 6, 8, 10, 11.5, 12 and 14) is thus 8 mm. So the part numbers seem to be 84500 for the plug (CPU side) and 84553 for the receptacle (logic board side) as per the datasheet, and DigiKey seemingly lists the connectors as 84500-102LF and 84553-101LF. (after the dash, the first number seems to refer to rated mating cycle amount, 0 for 50, 1 for 100, 2 for 200, the second to the plating type (9 or 0), the third one idk what it refers to, and the LF stands for lead-free)

For the older G5s (AGP/PCI), mated height seems to be 5.5 mm. I measured it to be 5.12 mm directly (since I have a desoldered socket lying around), rounding to the nearest available height seems to yield 5.5 mm. The part numbers are 84500 for the plug (CPU side, unchanged) and 84502 for the receptacle (logic board side) as per the datasheet. DigiKey lists the 84502 socket as 84502-101LF.

The motherboard sockets seem to be out of stock at most places, but it seems like there's a few resellers which might have it, if you look around. The CPU side plugs seem to be in stock both at DigiKey and Mouser.

 

[Matias_]

Interesting finds! A while back I was researching those frustratingly unobtainium Airport Runway cards for the late 2005 PMG5 card, trying to evaluate if it would be easy to design a replacement (I think it might be).

I was in a similar position in regards to trying to identify a weird SMD connector. I asked some EE friends and I think we ended up on "Molex SlimStack Board-to-Board Receptacle" but I don't have any real boards to measure, nor could I find high resolution pictures and I also don't have any PCB designing experience so I shelved that project for the time being.

If you are still interested I can provide pictures of the 2.5GHz G5 daughtercards from the Quad, I have 3 sets of them that are dismantled from the LCS but still have the VRM heatsink attached (I'd rather not remove them if I don't have to). I can't provide measurements right now because my set of calipers broke and I don't know where I left my spare but I think they are identical in size and almost identical in components, they just have some additional VRM components that are left out on the 2.0GHz and 2.3GHz daughtercards.

 

[Nullcaller]

Thanks!

I was in a similar position in regards to trying to identify a weird SMD connector. I asked some EE friends and I think we ended up on "Molex SlimStack Board-to-Board Receptacle" but I don't have any real boards to measure, nor could I find high resolution pictures and I also don't have any PCB designing experience so I shelved that project for the time being.

Yeah, from my little googling session just right now, I think finding the exact connector match is probably going to be more difficult than finding a needle in a haystack. With the needle, at least you can theoretically get filthy rich and buy an MRI machine, so that it comes out flying.

I've also looked at the Molex stuff, and I honestly don't think that's it. The runway card connector has some weird funky stuff on the edges of the connector, but there's nothing like that on the Molex connectors. I think it'll probably work, though, if you find a close enough match in terms of size and pitch. I know this connector type as the 'FPC connector'. Virtually every connector inside a modern phone looks like that now, and they usually go on little flexible printed circuit boards (hence the name) that connect various components inside phones.

Remaking the runway board is a fun project idea, though. You can't think of a better starting point EE project. Datasheets for the older PMG5 model seem to suggest that the gold fingers connector on the side of the runway card is just PCI in a weird form factor (though don't go plugging in any mini PCI cards you have lying around into that connector, 'cause it will go up in flames). And it seems like the cards from older PMG5 models are compatible with the newer models, so I would assume it's still PCI even on the Late 2005 PMG5s, with their fancy new PCIe connectors. It seems like all the runway card really is, is just a few decoupling caps on what is probably a 2-layer board. Maybe 4-layer, if someone at Apple was feeling fancy that day, and wanted to have a ground plane between the signal layers or something. So all you have to do, is figure out what values those caps are, and how not to screw up the signal integrity. And also, the connector part number, yes.

If you are still interested I can provide pictures of the 2.5GHz G5 daughtercards from the Quad, I have 3 sets of them that are dismantled from the LCS but still have the VRM heatsink attached (I'd rather not remove them if I don't have to). I can't provide measurements right now because my set of calipers broke and I don't know where I left my spare but I think they are identical in size and almost identical in components, they just have some additional VRM components that are left out on the 2.0GHz and 2.3GHz daughtercards.

If you have some spare time to take the photos (or measurements), then send them my way! Thanks!

What I want to know is kind of the positions of heatpipes and how they're attached to the VRM heatsinks. Also the diameter of the heatpipes, because I can't really tell from the pictures. I know the heatsinks are pretty much the same between the Quad and the 2.0 GHz cards, but (1) I will obviously be trying to make my own little Quad-like heatsink and (2) maybe someone will want a model of the Quad VRM heatsink eventually, you never know. I just think it's better to make the thing as close to the real deal as possible, then it might be useful to people as a reference thing, and not just to me as a do-it-once-then-forget kind of thing.

And as for removing the VRM heatsinks, I honestly don't think the VRM heatsinks should be detached from the daughtercards, like, at all, ever. I detahced mine from the spare 2.0 GHz CPU I had, and the gluey thermal adheisive pad thingamajig isn't holding on to the heatsink as strong as it did before. Which can probably be either mildly bad or pretty fine. On the Quad processor cards I think this has a chance of being more than mildly bad, so don't do it.

You could probably replace the pad things with thermal paste, and it'll probably be better in terms of cooling, but idk whether it'll be as good in terms of longevity.

 

[Nullcaller]

So about that runway card FPC connector. I've tried looking through DigiKey's catalogue of 40-pin FPC connectors (it's actually smaller than you'd imagine), but that yielded nothing. I did suspect Panasonic for a small while, but ultimately couldn't find a perfect match for the runway card connector.

But when that failed, I had an idea for another angle. The runway card isn't the only thing Apple ever used the A1126 combo WiFi/BT card with. (Naturally, I've memorized the model number by now) So if you could find schematics of other Apple products using the A1126 card, they'd probably have a convenient little label above the connector, telling you exactly what it is. Well, spoiler alert, they do. But the story is way more intersting than that.

Here's the schematic I found first. It says it's for an iMac G5, which I was searching for, but what it actually is for Late 2005 15.2" PowerBook G4. You can tell, because it says "PB15" on the first page, and has everything connect to the "Apollo CPU (MPC7447)", which just smells like a G4 chip. It also can't be a 2004 or Early 2005 machine, because those ones don't have the connector for the A1126 card, and, as we will now find out, this one does. Here it is:

With a convenient label above, as promised. If we search up QT510806-L111, we stumble upon something called Foxconn Interconnect QT51 series (datasheet attached), and would you look at that!

You may notice, however, that the connector doesn't exactly look like the one on the runway card. Let's see what iFixit has to say about that. The Airport card replacement guide doesn't seem to show what the board connector looks like. It does show that the board is connected to some sort of extender, however:

(courtesy of iFixit)

I've also looked through the logic board removal guide, which doesn't seem to contain photos of the extender, but it does contain this photo here, which shows the connector to which the extender cable connects:

(courtesy of iFixit)

Looks pretty similar to the datasheet, huh?

But wait, what about that iMac G5 I was looking for? Maybe we can find the schematic for the iMac G5, and then we'll know for sure. If it has the same connector part number, it must be the right one!

Wait, what's this here? A schematic for the iMac G5? Let's see then!

Ah. Well then, the extension must have had a different connector, and the PowerBook G4 datasheet lists the board connector instead. Let's see what the datasheet (attached below) says about the aptly named 20-5602-080-041-829.

Well... That doesn't look like it at all. IFIXIIIT!

(courtesy of iFixit)

Buh waih... That's an iMac G5. And it has... a different connector... So... The runway card, the iMac G5 and probably the PowerBook G4 all have different connectors for the A1126 Airport combo card. It seems like the iMac G5 uses the 20-5602-080-041-829 connector, and the PowerBook G4 the QT510806-L111 connector, and to know what the runway card uses, you'd pretty much have to have a schematic for it.

So, in short, it doesn't matter what connector you use, as long as critical dimensions are the same and they work together. Mind you, that's not me talking, that's Apple. In any case, you now have two datasheets to work with, and, most importantly, the critical dimensions for the connectors. Thus, as this forum's resident self-proclaimed interim chief connector detective, I consider this mystery solved.

(20-5602-080-041-829: "And I would have gotten away with it too, if it weren't for you meddling kids!")

 

[Nullcaller]

Edit: I'm stupid. I've been working with a 970 board, not a 970FX. But the datasheet I was using is for a 970FX. So my pinout is only really valid if the die pad designations are the same between the 970 and the 970FX. Given the fact that the datasheet for the non-FX 970 doesn't really seem to exist (at least I couldn't find it), and that 970FX is just scaled-down 970, and that Apple doesn't really seem to have changed the boards between 970 and 970FX variants, I think that the pad designations are probably the same.

A quick update. As of late, I've been interested in understanding how elastic interface works, and how the North Bridge is connected to the CPU dies on the Power Mac G5. So today I spent some time with a multimeter and one of the low-end 970FX 970 processor boards I had lying around, and I have so far been able to produce the attached file. It's a partial pinout for the 300-pin connector, where I've identified the power and ground pins, as well as elastic interface I/O.

One fun thing about the 300-pin connector, is that it appears to mostly consist of shielding for the elastic interface. The ground pins don't seem to really do much otherwise, and there are over 5 times more of them than there are supply voltage pins. The supply current is distributed across 25 pins, which to me initally seemed like a low number, but it kind of checks out, if you read the Amphenol MEG-Array specs. The connector is rated for 0.45 amps of current across all contacts at once, and at 100-150 watts of power consumption, the supply voltage pins will only see 0.3-0.5 amps of current each.

I don't know whether the pinout is the same on the Late 2005 G5 Power Macs, but the addition of the power terminals to the CPU cards to me seems to suggest that the pinout would in fact probably be the same.

Be aware that the pinout may conatin mistakes and is provided with no warranty whatsoever, under CC-BY 4.0 unless forum rules state otherwise. Also, do note that the pinout itself won't be that useful or make much sense without additional information from datasheets, manuals, schematics, application notes, etc. Some of them are attached below, some of them you can probably find on the Internet yourself. Feel free to message me if you have something particular in mind, though.

I intend to release more detailed versions of the pinout, with more pins identified, when I have the time to actually identify them.

 

[Nullcaller]

Edit: I'm stupid. I've been working with a 970 board, not a 970FX. But the datasheet I was using is for a 970FX. So my pinout is only really valid if the die pad designations are the same between the 970 and the 970FX. Given the fact that the datasheet for the non-FX 970 doesn't really seem to exist (at least I couldn't find it), and that 970FX is just scaled-down 970, and that Apple doesn't really seem to have changed the boards between 970 and 970FX variants, I think that the pad designations are probably the same.

Immediate followup: here's v0.2 of the pinout, because I missed some EI signals

 

[Nullcaller]

Edit: I'm stupid. I've been working with a 970 board, not a 970FX. But the datasheet I was using is for a 970FX. So my pinout is only really valid if the die pad designations are the same between the 970 and the 970FX. Given the fact that the datasheet for the non-FX 970 doesn't really seem to exist (at least I couldn't find it), and that 970FX is just scaled-down 970, and that Apple doesn't really seem to have changed the boards between 970 and 970FX variants, I think that the pad designations are probably the same.

I've had some time to identify more of the pins, so here's yet another version of the pinout, v0.3.

A lot of the pins are proving somewhat difficult to identify, though, seemingly because they're connected to the processor through some other components. I also seem to have mislabeled some of the pins as 'ground' on v0.1 and v0.2 pinouts (the ones that clearly stand out from the general 'checkerboard' grounding pattern) for the same reasons. The resistance to ground on these pins is indeed very low (~50 ohms), but it's quite a bit higher than on other ground pins (my multimeter shows 0.0 ohms).

I hope to identify more of the pins soon.

Edit: I've been able to immediately identify some more signals, so I'm also attaching v0.4

 

[ediflorianus]

So about that runway card FPC connector. I've tried looking through DigiKey's catalogue of 40-pin FPC connectors (it's actually smaller than you'd imagine), but that yielded nothing. I did suspect Panasonic for a small while, but ultimately couldn't find a perfect match for the runway card connector.

But when that failed, I had an idea for another angle. The runway card isn't the only thing Apple ever used the A1126 combo WiFi/BT card with. (Naturally, I've memorized the model number by now) So if you could find schematics of other Apple products using the A1126 card, they'd probably have a convenient little label above the connector, telling you exactly what it is. Well, spoiler alert, they do. But the story is way more intersting than that.

Here's the schematic I found first. It says it's for an iMac G5, which I was searching for, but what it actually is for Late 2005 15.2" PowerBook G4. You can tell, because it says "PB15" on the first page, and has everything connect to the "Apollo CPU (MPC7447)", which just smells like a G4 chip. It also can't be a 2004 or Early 2005 machine, because those ones don't have the connector for the A1126 card, and, as we will now find out, this one does. Here it is:

View attachment 2530501

With a convenient label above, as promised. If we search up QT510806-L111, we stumble upon something called Foxconn Interconnect QT51 series (datasheet attached), and would you look at that!

View attachment 2530503

You may notice, however, that the connector doesn't exactly look like the one on the runway card. Let's see what iFixit has to say about that. The Airport card replacement guide doesn't seem to show what the board connector looks like. It does show that the board is connected to some sort of extender, however:

View attachment 2530507
(courtesy of iFixit)

I've also looked through the logic board removal guide, which doesn't seem to contain photos of the extender, but it does contain this photo here, which shows the connector to which the extender cable connects:

View attachment 2530508
(courtesy of iFixit)

Looks pretty similar to the datasheet, huh?

But wait, what about that iMac G5 I was looking for? Maybe we can find the schematic for the iMac G5, and then we'll know for sure. If it has the same connector part number, it must be the right one!

Wait, what's this here? A schematic for the iMac G5? Let's see then!

View attachment 2530513

Ah. Well then, the extension must have had a different connector, and the PowerBook G4 datasheet lists the board connector instead. Let's see what the datasheet (attached below) says about the aptly named 20-5602-080-041-829.

View attachment 2530516

Well... That doesn't look like it at all. IFIXIIIT!

View attachment 2530517
(courtesy of iFixit)

Buh waih... That's an iMac G5. And it has... a different connector... So... The runway card, the iMac G5 and probably the PowerBook G4 all have different connectors for the A1126 Airport combo card. It seems like the iMac G5 uses the 20-5602-080-041-829 connector, and the PowerBook G4 the QT510806-L111 connector, and to know what the runway card uses, you'd pretty much have to have a schematic for it.

So, in short, it doesn't matter what connector you use, as long as critical dimensions are the same and they work together. Mind you, that's not me talking, that's Apple. In any case, you now have two datasheets to work with, and, most importantly, the critical dimensions for the connectors. Thus, as this forum's resident self-proclaimed interim chief connector detective, I consider this mystery solved.

(20-5602-080-041-829: "And I would have gotten away with it too, if it weren't for you meddling kids!")

Q: (I am a bit off-topic,sry), Is it possible to use mSATA ssd instead of a wifi card in the G5?(or maybe thr MP,I don't remember exactly what slot the 4,1 had, I have to open up).
I do know the G4(MDD) has a laptop(ibookG3/4)airport wifi card slot probably Card-Type2... in theory that should pe possible to fit some tipe of "adapted" sd-card or CF-to-CT2.... but that is not the case on G5& Newer.... not sure about the protocols dow...
L.E. I think I seen the 300pin-out to the cpu published somewhere... so you may have wasted some time on that...(not quite sure where It was published... but it was no secret).

L.E.2. Here is some info on the PPC cpu,PowerPC G5 microp. Archive supplemental referance doc - copied from Power Mac G5 Developer Note(Legacy) - 24 PM G5(june 2004).pdf I can try upload the document if you Wish (or can't find it.)

 

[Nullcaller]

Q: (I am a bit off-topic,sry), Is it possible to use mSATA ssd instead of a wifi card in the G5?(or maybe thr MP,I don't remember exactly what slot the 4,1 had, I have to open up).
I do know the G4(MDD) has a laptop(ibookG3/4)airport wifi card slot probably Card-Type2... in theory that should pe possible to fit some tipe of "adapted" sd-card or CF-to-CT2.... but that is not the case on G5& Newer.... not sure about the protocols dow...

It's impossible to be off-topic in this topic, since this topic doesn't really seem to currently have a topic

As for the card shenanigans, as far as I know the Airport card connector that's physically on the G5 motherboards (both CPC925/U3 and CPC945/Kodiak/U4 based, or PCI/PCI-X and PCIe variants, respectively) is just glorified PCI in a proprietary form-factor. So in theory, you can make your own little PCB with an edge connector (which is easier than you probably think it is, except for the hullabaloo you'll probably have to go through to ensure proper signal integrity) that fits the slot, make an extension cable and terminate it in a real full-size PCI slot.

At that point, nothing prevents you from plugging in any PCI card that does whatever you want. There's no guarantee that it'll work, though, for two obvious reasons:

• No guarantee OpenFirmware will like it, because it wants something different from expansion cards than your usual BIOS/UEFI
• No guarantee that there aren't some arbitrary restrictions that Apple put on the Power Macs so that the Airport card connector can only work with Airport cards

So, in short, that slot won't work with mSATA/miniPCIe/M.2/etc anything without some adapting from one protocol to another. Even if some connectors seem physically compatible, inserting something that isn't meant for the G5 Airport card slot into it will at best not work and at worst short power to ground and fry the whole motherboard.

I don't know which protocols the Airport cards on the MDD G4s and G3/G4 iBooks use, but I do have this interesting iMac G4 schematic lying around, which says that the 'wireless connector' is apparently, again, just glorified PCI. And where there's two data points, there's always a line that goes between them, which in this case would suggest that every Airport card might just be PCI-based.

 

[Nullcaller]

L.E. I think I seen the 300pin-out to the cpu published somewhere... so you may have wasted some time on that...(not quite sure where It was published... but it was no secret).

L.E.2. Here is some info on the PPC cpu,PowerPC G5 microp. Archive supplemental referance doc - copied from Power Mac G5 Developer Note(Legacy) - 24 PM G5(june 2004).pdf I can try upload the document if you Wish (or can't find it.)

Sorry, I was so busy replying to your message (and staring at Power Book G5 prototype schematics, which I've published on the forum yesterday) I didn't notice the edits 😅

If you've seen the pinout for the 300-pinout connector and you can find it again, then please please please send it my way. Same goes for if you know where to find schematics, diagrams or boardviews relating to any of the G4/G5 Macs.

As for the document you've linked, thank you! Now, unfortunately (or, rather, fortunately) I already have it. But more important for me in this case is the knowledge that the IBM documents I've been reading aren't really that confidential. I've been trying not to publish like everything I have in a single message and, only bringing up documents when it's important to do so. But I now see that this has been a pointless endeavor.

So here's pretty much everything of importance that I've amassed about CPC945 and 970FX, including the aforementioned user manual:

 

[Nullcaller]

And here's more for 970MP: