[NTLK] Notephone and OMP/MP100 issues

[NewtonTalk]

I own seven or eight Notephones, most of them complete and in their original
packaging, and over time I've had three or four from other people on my
workbench. They all have the same problem: They don't "hang up" when you put
the receiver back on the cradle. So the toll office out there thinks your
phone call isn't yet finished. That's why you'll never get a dial tone for
your next phone call unless you temporarily unplug the phone. This problem
hides in the base unit's mainboard, and it is to a certain degree
temperature-related. Most, but not all, Notephones will work fine for a
short time if you put them in your fridge for an hour before making the
call. 

Don't waste your time adding the cradle switch to your suspect list. The
switch is perfectly OK.

At one time I thought I had fixed this problem by replacing some capacitors
that had leaked, but I was mistaken. This Notephone is now in Sonny's
possession, and eventually the problem came back. 

The Notephone's Newton will quite happily do faxes when you furnish it with
the correct cable. The problem is that even in Germany a standard German
phone cable will not work because Siemens did their own thing cable-wise.
You'll have to reverse two wires to make it work. I dimly remember there's a
further cable change required if you want to make the Notephone run in the
US, but off the top of my head I'm not sure. 

The Notephone was never sold with an English OS Newton. Those that are out
there were all modified by yours truly. They DO look genuine, though,
because I not only replaced the mainboards, but also the touchscreens (to
get English silk screen buttons) and all decals that are visible to the
naked eye. I'm glad to hear that people won't part with their English
Notephone for less than a thousand bucks. Always nice to have one's work
appreciated :-)

The problem with the silent Newton is a completely different cup of tea.
This is an problem that eventually befalls every Notephone Newton, OMP, or
MP100. Normally the Newton only appears to be silent, but isn't. If you set
the Newton to maximum volume and hold it close to your ear, you normally
still hear the sound, albeit very faintly.

The reason is a 100uF 4V capacitor that has leaked. If you remove the back
part of the case, you will (assuming you look at the Newton with the battery
compartment pointing towards you) find it at the bottom left-hand corner to
the left of the white fuse. That's close to where the speaker wires are
soldered to the board. The capacitor is silver, cylinder-shaped and has a
black rectangular "housing" around it. Replace it, and the sound will be
like new. Make sure to clean the area around the capacitor with some
cleaning fluid after removing the old capacitor and before putting the new
one in.

You'll probably have a hard time getting a 4V capacitor. Higher voltages are
OK, but make sure the capacitor isn't bigger than the original, otherwise
you wouldn't be able to reassemble the bottom case part correctly.

While your Newton is open, you should also replace C51 (3.3uF 35V). This
capacitor is known to cause display problems that make the Newton impossible
to use, as Erik Johnson found out about two years ago. This component is on
the "wrong" side of the mainboard, so you'll need to remove it for the
replacement.

Taking an OMP/MP100 apart and putting it back together isn't for the faint
at heart. Some time ago I wrote instructions how to do this. However, since
these instructions are still missing the required DoPa approval, which is
entirely my fault because I'm so darn busy taking care of other issues at
the moment, they're not yet available on my website. If you want to have a
look at the ugly and incomplete draft version, be my guest:

 
<https://www.pda-soft.de/scratch/How%20to%20take%20apart%20an%20OMP%20or%20N
ewton%20MessagePad%20100.docx>

Cheers

Frank

-- Newton software and hardware at http://www.pda-soft.de