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I'm surprised no one has cloned that CAS PAL chip yet, it's simple and much easier than most of the other reverse engineering efforts I've seen people do.

One of them looks like the Video Explorer:

I think something like the ST L7805ABV may work. Not all 7805s are quite the same and I don't remember what qualities are typically required, but the L7805ABV at least shows an example of it being used for negative voltage: I think the numbering may be incorrect on the schematic symbol, but...

I think that might work, maybe something like 10nF/1000Ω, though the mouse button is active low but I assume the timings will still work the same... Here's most of the driver. I tried to comment and refactor most of it to make it much more readable. Most of the interesting stuff is down towards...

I think I see the check, though I'm not entirely certain. It looks like it's using the mouse button line by setting it as an output and asserting it for ~1ms, then switching back to input, checking to see if the mouse button is still asserted after ~7us, and then checks to make sure it's not...

I wish you luck, I may be wrong but on first glance at the code it looks like they went through a lot of effort to obfuscate things. Guess they really didn't want their code/hardware cloned. I may see if I can take some of it apart and post here.

Well if you can desolder the connector on the display board you could probably use a direct board IDC crimp like 3240-26-00, M50-3801342, or FFMD-13-01. The cable wouldn't be detachable from the display anymore but at least the other end would still be.

That's the odd part, they have the bigger version which seems to be identical in everything but size, but no sign of the smaller one even existing even going back to older catalogs. It's possible something like HARTING 15290262501000 or 15290262502000 might fit (or be modified to fit) but I...

You could likely build your own cable just by crimping the connectors on, but I don't know of a source for the display side connector unfortunately.

That's moving the contents of memory address $2AE, so whatever value is stored in the ROMBase global variable.

I would if not for the issue of redistributing copyrighted code. While I think you can export the annotations and apply them to the binary later, I don't think it quite gets everything like equates, and preferably everything would be rewritten into assembly files that are easier to read and...

I typically just use Ghidra to decompile. Assuming it works like other systems, that's just for the reset vector, and then the first read to regular ROM address space disables that.

That's for the Ginty ROM code, which isn't present in most Quadra ROMs it seems, it is in the 660av and 840av ROMs though. The only way I think it might work is if the system is in 24-bit addressing mode at that time, which if I understand correctly it would shift the ROM addresses around...

Maybe we're not looking at the same code. From the Quadra 650/800 for example: movea.l (ROMBase),A2 ; Load ROM starting address ROMDiskLoop: bsr.w CheckForROMDisk ; Look for a ROM disk bne.b NextROMDisk moveq #0,D1 move.l A2,D2 move.l...

I don't think there's any need to replace it, but if you need to replace one in the future the OP07CD series works fine. Q20 should have battery voltage on one side, and +5V on the other (when the +12V is on).

There was actually a removable system as well. Two card slots above the floppy drive, likely similar to PCMCIA slots in size and shape, insertable and ejectable while the system is running. It never made it out and was likely abandoned judging by the "lazy" design decision on the M5126 that...

I've seen that happen before, I think I have one board that had Q20 requiring 10-11V on the gate to get up to 5V. It's a very unusual failure, I swapped the OpAmp with a slightly better one to give it an extra volt (the OpAmp+ is connected to +12V) since I didn't have a spare MOSFET.

You could theoretically rewrite the ROM to move all hardware addresses to the top of memory and then either: Replace/recreate the glue logic or Move/add a 68000 to the PDS card and rewrite memory accesses for hardware

You can see the +5V from either the metal heatsink on Q16 or from pin 2. Occasionally the connection to the heatsink isn't great so if you have trouble getting a reading or it doesn't look right then check pin 2 instead. 6.2V is the voltage from the battery. Q16 brings it down to 5V. I'm...

It definitely seems like there's either unstable +5V or some weird bus errors based on the errors. If you have an oscilloscope you can look at the +5V to see if you see any fluctuation or drops. If you're interested at all, here's what each error means: 00000010 0000CD37 0x10 is a failure...