Warning: This story is a little long, and occasionally a bit technical. Then again, maybe you'll find the info interesting nonetheless.
Even if you don't, it might still be a nice read.
The following production has cost yours truly one solid week's worth of nights...
Frank: Slightly dumb hobby service technician who earns his living by pretending that he is a programmer.
Paul: The incredible Guyot, technical adviser.
Dale: Mainboard provider.
Andreas: Mainboard provider.
Martina: Amazingly patient wife, who has every right to expect other activities at Easter.
Miscellaneous: Apple Newton hardware developers who could have prevented all this.
Microscope: Originally located in Florida. Bought from Germany in an eBay auction, sent to a colleague's sister's house in
Florida, picked up there on the occasion of a holiday trip and lugged back to Germany.
Weller WSD 50: Frank's wonderful soldering station.
Voltcraft 3650: Frank's multimeter.
BeeOne, BeeTwo: 9 Volt batteries for multimeter.
BeeThree: 9 Volt battery, because two aren't enough for such a project.
Reddy and Blacky: Tiny test probes bought for this very project at EUR 15.00 each (ugh...).
Gossen Model 1: Frank's decades-old adjustable laboratory power supply.
Home video releases:
(Spoiler warning: This will unravel one of the most mysterious Newton mysteries).
Set in 2006, the story begins with Frank's getting yet another Newton on his workbench that shows a classic defect:
The Newton tries to power up, chimes, changes his mind, switches off again and starts over. Usually this is repeated
twelve times, then the Newton gives up.
The defect in question used to be repaired by David Watson, also known as Dr. Newton. Unfortunately, David seems to
have dropped off the surface of this planet, making it impossible to get at information that would be necessary to
fix this problem.
Up to the day that marks the beginning of the story, Frank has never been able to fix such a board. He has always had
to replace them. The result is a small cardboard box containing five Newton 2000 / 2100 mainboards that all suffer
from the same disease.
Frank briefly contemplates making the sixth one join its five unfortunate pals in the box, but changes his mind.
Preparing and accomplishing a large-scale expedition to fix one single Newton mainboard would of course make no
sense whatsoever. Frank could make much more money in much less time by pretending to be a programmer.
On the other hand, preparing and accomplishing a large-scale expedition to fix six Newton mainboards would make
no sense whatsoever, either. Frank could still make much more money in much less time by pretending to be a programmer.
As a consequence, Franks starts preparing a large-scale expedition into the depths of Newton hardware. Comparing every
single component on a dead board to its respective component on a working board isn't exactly a professional way of
doing service, but with no technical information whatsoever at hand it is the only way available to dumb service technicians.
The next day sees Frank putting a Newton mainboard on his employer's copy machine and experiment with different
settings until he has a decent photocopy of each side of the board, enlarged to a size of about 0.4m by 0.3m. After all,
even a dumb service technician is aware of the danger of forgetting which of the hundreds of components has already been
tested and which hasn't, so he wants to mark the tested ones on the copy.
On his way home Frank secures himself to BeeOne, BeeTwo, BeeThree, Reddy and Blacky.
0.24 square meters of table space not being available close to the workbench, Frank tacks the copies to the wall,
resulting in his wife's tendency to frown with the facial expression of someone suffering whenever she passes them,
which happens approximately twelve times per hour.
Frank decides that, while he is at it, it would save time to not only compare two boards, but three,
the third one being one that suffers from another standard defect: The Newton does not start up. Brainwiping such a machine works
just fine, but the Newton never starts up after it. Frank has an inkling that these two defects are only two different results of
basically the same problem.
Equipped with three 2100 boards and a pen, Frank fires up his trusty multimeter and sets out on his leap in the dark.
For a start, he decides to measure and compare only standard semiconductors like transistors and diodes. Resistors die
far less often, the death of electrolytic capacitors is usually visible and smelly, small capacitors hardly ever die
at all, and the sheer amount of pins on integrated circuits is likely to make him give up before he starts.
Two and a half nights later, all diodes and all transistors have been compared. Unfortunately, nothing out of the
ordinary has been found.
The logical choice would now be to start comparing the integrated circuits. But the amount of pins still dejects Frank,
so he decides to have a go at the resistors.
He strikes gold at about 3am during night #3. R120, which should have a resistance value of 36kOhm, has a resistance
value of 70kOhm. Replacing it fixes this particular mainboard, which will make cast member Dale G. very happy because
Frank has promised to fix his Newton for free if his mainboard happens to be involved in a successful outcome of Frank's crusade.
Overwhelmed by his success, Frank decides to call it a day and sleep a bit for a change.
As of then there's one mainboard less that must be compared to the working one. Unfortunately, there are still six left,
since R120 is perfectly healthy on all the other boards.
However, one leg of R120 is connected to a bit of circuitry surrounding a Maxim MAX1771 chip. This is an adjustable
high-efficiency DC-DC controller, i. e. a component that's supposed to convert a voltage into a different voltage. The design
around it corresponds to a Maxim application note Frank finds in one of his creased and dusty old data books. Since some
of the components' values do not exactly match those in the application note, Frank blows the dust off his old pocket calculator,
gets down to some serious calculations and thus determines that the Apple developers have intended the output voltage of their circuitry to be 5 Volts.
This voltage is missing. Unfortunately, it's missing on the working board, too. It doesn't seem to be that
Enter the incredible Paul Guyot. Having always admired his amazing knowledge of the internals of the Newton OS, Frank had
asked him a long time ago if he had an idea what exactly happened at the end of the startup chime
(remember that the Newton always powers off immediately after the chime). Paul had replied that the Newton was checking
for the presence of a voltage required at the PCMCIA card slots. At the time, Frank had compared the slot connectors of both
a dead and a working board, but hadn't found any difference.
5 Volts is a voltage that is
required for some types of cards. So Frank checks if there are any
PCMCIA specific integrated circuits on the board that might handle the slots' voltages. In his only stroke of genius ever,
he finds one SI9712 chip for each PCMCIA slot. This is basically a switch
matrix that routes 3.3 Volts, 5 Volts or 12 Volts to the card slot pins.
Frank measures that the 3.3 Volts and 12 Volts are present, but the 5 Volts aren't.
Unfortunately, they aren't present on the working mainboard, either. Hgrmpf...
Frank has another look at Maxim's application note. Aha... the MAX1771 has a shutdown pin!
Since the Newton usually shuts all unneeded voltages off to save power, it would make perfect sense to shut card-related voltages
off until they are needed. This leads to the second stroke of luck, namely Frank's measuring this voltage during and not after
the Newton's power-on sequence.
Goal! On working Newtons the 5 Volt supply is turned on for about two seconds (probably for allowing the Newton
to check that it is there), and then turned off again. On the dead mainboard the 5 Volt supply is
never turned on.
The question now is whether this is because on the defective board the Newton doesn't switch the MAX1771 on, or because it or
the circuitry around it do not do their job anymore.
Drunk with happiness Frank decides he cannot concentrate any longer and hits the sack. This is the end of night #4.
The next day Frank does something that should only be done if... if... well, actually, it should never
He sets crew member Model 1 to 5 Volts and connects its output to the output of the comatose MAX1771. After having
made sure that the fire extinguisher is still where it used to be, he switches both the Newton and Model 1 on at the same time.
Nothing happens. No sign of life whatsoever. No smoke, either, but a totally dead mainboard. F*ck...
This is the end of night #5.
One night later. Frank notices that there's no ROM board in the mainboard. He had removed it for his soldering and completely
forgotten about that. Slightly ashamed of himself, he puts it back and repeats last night's experiment.
Score! The Newton powers up. No more cyclic boot attempts anymore, it just powers up like it should and smiles at Frank.
It even stays on and works hunky dory if Model 1 is disconnected after the powerup (unless, probably, cards are inserted,
although Frank doesn't try this).
This, quite obviously, is a major breakthrough. Although it doesn't fix the defect, it allows to power the Newton up in a
way to backup one's data, which so far had never been possible.
This is the exact time Frank decides to change his schedule on short notice and inserts an hour of celebration accompanied
by a couple of bottles of decent Single Malt scotch whisky. Due to the nature of the celebration, the hour grows to more
than just one hour, and this becomes the end of night #6.
The last roadblock now is, of course, finding out why
this voltage is missing on the defective mainboard.
Frank decides to approach this problem in a somewhat pragmatical way by simply replacing the MAX1771. By now he firmly
believes to be kind of entitled to a little success that hasn't cost him nights. Greedy as ever (and because it's Sunday and
there's no chance to buy a replacement), Frank cannibalizes a MAX1771 from an organ donor board and solders it on the defective
board. He then makes sure that the ROM board is where it should be.
This is the end of night #7 and the beginning of another celebration session.
Final scene. Frank, humming under his breath, has just finished fixing mainboard #6. Every single one of these six fellows
has been fixed by replacing U34.
Got it? U34!! MAX1771!!!
Boy, one of these days I will start accepting donations...
Download this story as a Newton book