[NTLK] Cadillac prototype

[Matthias Melcher]

Wow! Congratulations on getting this really awesome machine!

I don;t know much about it besides its existence, but I do have quite some knowledge on the electronic design of the MP2x00. I'll try to explain what I see on your photos, just as a brain storm. Maybe something is helpful.

Power: the MP2x00 is very easy to destroy with the wrong power supply. Cheap power supplies for 8.5V can have much higher spikes that kill the Newton outright. You seem to experiment with a quality benche supply, which should be fine. Internally, the Newton generates multiple voltages for the LCD, the PCMCI ports, and of course for the basic electronics. I seem to rememeber 24V or 42V for the backlight (early consumer products do not have a back light), 5V and 3.2V for CPU and PCMCIA, and 12V

The empty battery slot backs up the Storage and probably a real time clock. This is only important if you get the device to run. Later models have Flash RAM that does not need the battery and a clock that uses only a supercap, no battery either.

PCMCIA has a 16 bit data bus, but can have a 32 bit bus in later versions. I t is possible that way to have the entire prototyping OS in a PCMCIA card and have no ROM on board at all. Prototype board that I have seen have relatively large flash ram PCBs for development. Production models have small ROM cards with two 4MB or four 2MB chips (16 bit data bus). Those ROM ar custom Apple chips.

IMG_7676: Nice! At the bottom right you see two potentiometers. One is like the sound volume, the other is likely contrast. You display showing nothin may just be low contrast. Try to adjust them first (It's know to have happend on eMates that were completely disassembled to repair the screen, only to find out the contarst slider was all the way down)

The pen is wires, which is rally surprising. The resistive touch system of the production model does not need a wire. Maybe they used a different digitiser here that requires the pen to be powered (inductive).

IMG_7677: So the model uses short PCMCIA cards in the back. These are rather uncommon and seem to be prototyping ports. The user port is in the front and full length.

IMG_7681: the yellow round cich connecter could be an NTSC video out port. If you have an oscilloscope, check the signal. NTSC is unmistakable. The other two are probably modem and audio

IMG_7685: we know that Apple made PCMCIA diagnostic cards. There are PCMCIA card readers out there that can read the 1993 paralle;l memeory cards, but they are few and expensive. *Don't* put these cards into a 200$ USB-to-PCMCIA reader! Those are made for very specific serial memeory cards and can;t read parallel flash cards. It would be really great to dump the contents of the card. The card descriptor tells us what the card type is and who manufactured it. Same with the smaller cards in the back. I assume you are located in the U.S.?

If I can see the ROM dump, I can tell you if it contains the firmaware, or if it is a diagnostic card. In any case, we can find and print text blocks and probably even images sotred on the card.

IMG_7690: the DIN port on the left seems to be the same serial port as on MP100's etc. . Since this is a prototype, this port may have a debugging stream on it by default, or may respond to requests from Hammer, a debugging software that runs on MacOS System 7 and can go into the deepest details of any Newton including single stepping through ROM code. If Hammer can connect here, at least you know that the CPU is running the firmaware just fine.

IMG_7710: the two 858512LTT are pseudo-static RAM chips with 4MBit memory (512kBytes). They must be backed by the coin cell battery to keep their content. This is where the newly installed apps are stored. Since the coin cell is missing, this memory is lost every time you take the device off the power supply. That's fine. The OS should reinitialize it and give you an error message.


IMG_7712: the PCMCIA card on the left has a slot in the back which indicates that it could be an IO card with a missing breakout cable. But the battery would cover the breakout, which makes no sense. The clear case states "ROM", so this may be the ROM containing the firmware, and the slot in the back may be a prototyping thing for reprogramming the ROM - just wild-guessing.

I have not seen dynamic RAM on the main board, so the empty slot marked RAM may be missing the matching card. Since you have all the other ards, this is unlikely though, and we just have not seen the RAM chips on the main board yet.

IMG_7726: that's quite an LED array there on the right. Missing coin cell, reset button. Two potentiometers at the bottom left, volume and contrast? T3 is a supercap for the clock?

Top right are two more pseudo-static RAM chips

IMG_7733: top left is  (prepared for) IR port

IMG_7769: the bigger bricks are likely voltage inverters and will humm if they work

IMG_7770: diagnostic short PCMCIA card, but may also contain the entire firmware


 - Matthias