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Connector seem to be similar to the SCSI LVD connector but with 80 & 40 pins…

Correction: The 68HC24 chips are called "Port replacement unit", which I suppose are the 68HC11 equivalent of a VIA or PIA, some kind of port extender to replace the pins of the uC when it's used with an external memory. Yeah it's much smaller (52pins) than an FPU. I'd say it's a 68HC11 of some...

Oh the gerbers are for the ROM cartridges, thought it was for the whole thing. Still useful I suppose.

No, the HM62256 is a 32kB static RAM. Is the FPU the yellow labelled chip? Possibly it asks the logic board to do calculations and compares them to what this one gives. The 68HC24FN is an evolution of the HC05 uC used as EGRET, likely one is wired to the sram and cartridges. Maybe it's...

It doesn't seem to list the E1 variant… As I said, you don't really need a full programmer, it can be done with a few components. I'll have a look later but I have other more urgent stuff for now.

Yes and no. Yes, because you can't use an EPROM programmer unless it specifically supports these chips. No because as I said, the bootstrap ROM makes it not so hard to program them with a simple circuit (basically a 12bit counter and an EPROM that you programmed with the code). It's even...

Well there's an OTP version of the HC05E1 (68HC705E1DW, in SOIC package it's only available in OTP) that might still be available in a few places, but I don't know for how much, and when they say "pulled from devices" I'm not what they are worth if they are already programmed with something...

Yes that's @max1zzz 's schematics from reversing the board, which just confirms the other ones. Again, while different versions used some GPIOs for different purposes, there is no "scrambling" of the pins with respect to the regular 65HC05E1, it's just that they started manufacturing masked...

The problem with PLCC is size, there are other stuff around the chip… I started documenting the pinouts here. I don't see much of the "scrambled pinout" really, power and oscillator pins are still in the same place for what I've seen…

Pinout for the uC is in the datasheet, page 81. As for the use in macs, only the bomarc schematics seem to have them. Oh dear, I went again down the rabbit (eh, appropriate time) hole of digging the datasheets… It seemed like the 68HC705E6 could have been used as replacement, except the SOIC...

Sadly no, it doesn't have enough pins, only has 2 8bit ports, the original one has 2.5 (2 full 8bit + 1 4bit ports).

I had some look at the EGRET posts here and elsewhere some time ago… It seems there might be interest in recreating them. I don't really have the need myself, my LC-III works fine for now, but I figured I'd spawn a thread to discuss the issue. The various pinouts don't seem documented yet on the...

2AM CEST, might or might not still be awake 🙃

Just received some connectors in the mailbox…

Oh dear, what's this broken piece now? Just when I was about to put it back in the box, this piece fell of the mouse… I'm wondering, does Apple have shares in UHU or something… Oh well, let's clean the ball and rolls as well…

DAMN, I broke the backplate cover when putting it back because I didn't lock the logic board handle back up :-( More UHU Plast… Yeah, should be ok.

Some measurements for later…

Not really sure where to go from there, don't have experience with them.

Didn't have the time for a video but I took some pics of my Performa 5400/180 Black, which was in a box for some years… Also gave me an idea for some future hardware stuff…

I guess we'll have to fake ones with a 2x20 and 2x30… bleh 🤷‍♂️