no AC power needed 
Yes, another post about the eMate 300! I successfully replaced the rechargeable battery cells in the battery pack over the weekend. I actually had to do it twice, as the first time I didn’t do a decent enough job of ensuring all points of contact were contacting enough.
It’s a pretty straightforward process of replacing the actual battery cells, and reconnecting the temperature switch (cuts the current to ~100mA if temperature reaches 55° celsius) and thermistor.
I took a couple of photos to show the proper polarity for these connections at either end:
 temperature switch |
 thermistor and battery wires |
finished battery pack
I pretty much followed the directions at Frank Gründel’s site pda-soft.de, as well as looking at Wizbone’s quick writeup on Hack Canada. Very simple, even if kind of nerve-wracking since I’m ripping apart the only eMate battery pack I’ve ever seen in my lifetime (not that I couldn’t hop on eBay and pick up another eMate easily).
After assembling the battery, the eMate claimed it was charging the battery, but this wasn’t really the case. After I pulled the AC cable out, the device would shut off. Obviously a problem with the battery pack. I ended up testing it with a voltmeter and found that there was no current. Woops… I was too casual about taping everything together, and there was a break in the circuit. I set everything up again, and that seemed to do it. Did a bunch of testing with the voltmeter/ohmmeter just to be sure.
charging properly
The second time putting the pack together, it worked great. Charging properly, running on battery just fine. Success!
However, I noticed rather quickly that the touch screen was not picking up the stylus’ position properly. I’m not quite sure what the problem is, but I’m willing to wager it’s a case of the display cable becoming damaged by the springs of the screen hinge. There’s a good writeup on how to fix this problem, but if the cable is too damaged, I’d have to buy a replacement one. Not sure yet.
these should be straight lines
In the photo on the right, those lines that you see were drawn by me smoothly drawing a straight line. This is after running the Setup app and recalibrating the stylus positioning a couple of times.
Hopefully it’s just some minor issue that won’t require full replacement of the screen cable. We shall see!
Related posts:
I should try this with my old Powerbook G3 baterries.
Pismo or Wallstreet? There’s instructions on replacing the cells in the Pismo battery pack, although it looks much more involved: http://people.wallawalla.edu/~Rob.Frohne/Powerbook/Pismo/Battery/