7. The power supply: (schematic diagram under development)

Your Pilot main internal power is regulated to 3.3V using the Maxim MAX720 (3.3V Palmtop computer and flash memory power supply regulator).

There is a 100.000 uF (!) capacitor (C2) to save memory data while replacing batteries. It also saves your data when batteries have bad or intermittent contact. Pilot will shutdown if you have a battery problem but data will be safe while the energy inside this capacitor lasts. The measured voltage drop over this capacitor after 1.5 minutes was 10% of initial voltage (3.3V)

There is a diode (code 607, D1) to prevent damage to your Pilot in case of reverse battery installation. I believe you can damage this component if you leave batteries reversed for a long time due to overheating. Batteries will overheat also and can leak or melt plastic pieces.

My Pilot measured currents

(with Fluke 87 at 28 degree Celsius and batteries at 3.074 Volts)

OFF = 150 uA;
ON (idle) = 15.7 mA;
ON (Playing Chess Pilot X Pilot, no sound) = 50mA average, 54mA peak
HotSync'g = 50mA average, 55mA peak

Contrast setting effects:
All the way up (light) = 14.8 mA
Best setting = 15.7 mA
All the way down (black) = 18.3 mA

Other effects: (due to repeated interrupts I think)
Sounds: Peaks of 45mA before and after beeps (does not matter which beep/sound)
Holding Pen at silk-screen area: 22 mA
Holding Pen at display area: 26 mA
Holding function buttons: 44 mA
Holding Up or Down buttons: 33mA
Power Off to On: 64.4mA peak

My New PalmPilot Professional measured currents

(with Fluke 87 at 24 degree Celsius and batteries at 2.930 Volts)

OFF = 450 uA;
ON (idle) = 16.48 mA average;
ON with display lit = 48 mA; <============ around 300 % more current drawing !!!
HotSync'g = 50mA average, 55mA peak

You can use external batteries with clips to power your disassembled Pilot !

MAX720External Power

Future power supply schematic diagram

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