[NTLK] Transobs and zeners and smoking newts and smoking emates...

From: Frank Gruendel (newtontalk_at_pda-soft.de)
Date: Tue Jun 21 2005 - 16:44:20 PDT

If I remember correctly, which I think I do...

As for the eMate, the part labeled "DZ1" is a
1N713 (used to be made by Motorola I think).
This is a 9.1V zener diode, which could be
replaced with e. g. 1SMB5924BT3 or something

The component in the 2x00 Nweton labeled D2 is
NOT a zener diode, but a 10 Volt transorb.
The original part was made by General
Instruments, part name was KNP76GI. It can be
replaced with e. g. TPSMB10.

A transorb sits patiently between power and
ground, being utterly bored because only seeing
the original Newton's AC adapter's voltage
of 7.5 Volt, it can never conduct because it's
a 10 volt transorb.

However, if ever a spike occurs that's more
than 10 Volt, the transorb will happily short
this spike out, killing itself in the process.
After that the power supply is shorted out and
hence the mainboard is more or less protected. Unless...

...you attached a third party adapter that
does not remove the voltage as soon as
it senses a short, like the original Newton adapter
does. In that case the supply will pump as much
current as it can into the dead transorb. This won't
harm the transorb since it is dead anyway, but it
will make the mainboard very hot around the transorb.=20


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