Testing to see if you really killed the Zipit
Before you ask, no, there isn't a fuse that you can replace...
A lot of people seem to have plugged the wrong power supply into the Zipit
and killed the Zipit. The Zipit electronics appear to be only able to handle
a maximum of 6 volts on the external power plug. Here is a quick way to
determine if you totally wiped the electronics out or if it is in
the Zipit power supply circuit.
The Zipit power supply consists mainly of a Linear Technologies LT3406 (U12)
to derive the +3.3 volts from either the External Supply or the LiION battery.
The LT3406 has an absolute maximum rating of 6 volts, if you plug in an
external supply greater than 6 volts you will let the magic smoke out of
There is a way to see if the main board is completely wiped out. You can make
a cut with an X-acto knife and use two fresh alkaline AA batteries to
try to power the Zipit. Do not use the 4 volt LiION battery for this test,
that will blow the electronics!!!
Typically, a new akaline AA cell is 1.6v, two of them will yield 3.2v, this
is well within 5% of 3.3 volts.
Open the bottom cover, pop the speaker loose from the case and tack it onto
wax paper or plastic wrap to protect the adhesive. Next, use a sharp blade
with your X-acto knife and carefully cut the PCB trace
that runs between the inductor (L2) and pin 3 of the LT3406
(U12 marked as LTA5). You can cut the trace by simply bearing down on the
knife, it is not necessary to "slice" it, just make a pressure cut.
Make two cuts in the trace and scrape it clear.
Make the cut as shown below.
Once the trace has been cut, you have now disconnected the +3.3 volt regulator
from the rest of the Zipit. Using the two akaline AA batteries in series,
connect the GROUND (negative) onto the large metal shield of the WIFI
transmitter (large 1" square metal shield). Next, using an X-Acto blade,
inject the POSITIVE battery voltage into the Zipit on the other side of L2
(inductor) from where you cut the trace.
See picture below for where to connect (note that the AMBER LED is lit?).
The GREEN LED of the Zipit should come on, this is good, the ARM CPU controls
the LEDs. Wait a moment and the GREEN LED should go out and the AMBER LED
will now come on. If you've gotten this far, you have just verified that
the Zipit power supply is burnt and the main electronics appear to be
However, if the LEDs do not cycle or are not lit at all, you have a fried
Zipit (or lousy connections to the batteries). :(
The power button is bypassed at this point, if you cannot get any LEDs to
light, don't bother with pushing the button.