Internal Rechargable Power Supply for NEC Starlet The following instructions will tell you how to replace the existing carbon-zinc or alkaline batteries in the Starlet with five NiCads and an internal recharger. With this circuit, the AC power converter will trickle charge the batteries as well as run the Starlet anytime the AC power supply is connected. The power switch will turn the Starlet OFF, but will not interrupt charging. WARNING: This will probably void any warrantee on your Starlet. CAUTION: Once this modification has been made, use ONLY NiCad batteries in the device; other battery types may explode or leak. CAUTION: Before you begin, save any programs resident in memory. If you perform this modification correctly, you will not lose memory; but better safe than sorry. DISCLAIMER: The modification works on my Starlet. I am not responsible for any damage to your property as a result of following (or not following) these instructions. Materials needed: 4 NiCad C-Cells 2 NiCad AA-Cells 1 Diode (4003 or equiv) 1 Resistor (approx 50 ohms, 1/2 watt) 1 9-volt, 500 ma power supply (Optional ... I bought this to replace the 400 ma power supply that came with the Starlet) Miscellaneous wire, solder etc. etc. 1. Flip Starlet on its top. Remove screws located at each corner. 2. Turn Starlet right side up. Gently pry up the keyboard baseplate from each side of the top locking device. The keyboard plate should unsnap and separate easily. 3. Pull the keyboard wiring harness (the white wires attached to a blue connector) from its socket. [The blue connector separates; pull gently toward the edge of the circuit board] Now you can open the case fully. 4. Unsnap the connectors for battery, speaker, and low-battery light. 5. Unsnap the brown display wiring harness connector. 6. Remove all screws attaching the circuit board to the bottom of the case, EXCEPT the one in the lower left corner. 7. Unscrew the post in the center of the circuit board. 8. Remove screws holding the metal bracket on the left side of the board. Remove the metal bracket. 9. Gently remove the circuit board from the case. 10. Turn the circuit board over. Note the solder pads running to the external power supply. The pad nearest the circuit board's edge is the positive (+) power supply (touches the sleeve of the AC converter). 11. Find the two pads on the bottom of the circuit board, corresponding to the "battery" contacts (they are marked on the top of the circuit board). One pad connects to a wide strip of foil. This is the negative (-) pad. The other pad is positive (+) [corresponds to the red wire]. 12. Solder a rectifier diode (+) end [no stripe] to the large (+) pad you found in step 10. 12a. Solder a [50 - 200 ohm] resistor to the striped end of the diode. (Note: choose the value of this resistor so the recharge current does not exceed the specifications of your NiCads). 12b. Solder the other end of the resistor to the (+) pad you found in step 11. This completes the recharge circuit. Make sure the leads are well insulated from contacting any other circuit components! 12c. Replace the circuit board in the case, and screw it down. Replace the metal bracket. 13. Find some space for your two AA-cells (I put one above the printer edge connector and the other wedged in the upper right corner of the case). Make sure the AA cells do not interfere with any other components! 14. Wire the two AA-Cells in parallel, and affix them in the areas you chose. Since there is no room for an extra C-cell, the two AA cells are wired in parallel to increase their current storage capability. 15. Unsolder the red wire from the left side of the battery chamber. Solder this wire to the positive (+) poles of the two AA-Cells. 16. Run a wire from the negative poles of the AA-Cells to the (+) contact on the left side of the battery chamber. Steps 14-16 connected the four C- cells with the pair of AA-cells so they are in series; supplying 5 * 1.2 = 6 volts. 17. Connect the remaining connectors to the circuit board. Stuff everything back into the case and tighten all screws. (Have patience here!). 18. Put four NiCad C-cells in the battery holder. Now try it out. If the screen shows garbage when you turn it ON, turn it OFF, hold down the RESET switch, and turn it ON again. The components I selected recharge the batteries in my Starlet at about 75ma. The resistor gets warm. I have not as yet checked to see how long the new circuit will power the Starlet without recharging. Good luck, and enjoy the increased portability of the Starlet!