reverse-engineering power

Guys and Doug, Did it have the battery at all? Often, I use this charging voltages to make a guess at operating voltage for missing power bricks and that capacitors. That diode could do one of two purposes: one might be for backward polarity by shorting and blow a fuse might be worse or as a mild voltage drop plus backward polarity protection. That capacitor serves to give you the voltage limit by that WV number minus about 20% WV printed on that cap. And that cap could be a clue but we need to be double sure that both legs of that cap is hooked directly to that power jack or one side is via that diode that you ID'ed. Try: first: hook up the voltmeter to the 74xxxx chip for 5v and ground. second: hook up that power jack with right size coaxial plug and to veriable regulated power supply at least 600mA limited third: start at 6V and chank up in 1V steps until it starts to work properly especially for the display's crisp startup lamps. Very common voltages due to the batteries: 8V (for 6V battery), 9V for 7.2V battery, 12V for 9V battery, so on until about @12V max. These voltages are used for rapid charging voltages. Jason D. email: jpero(a)cgo.wave.ca Pero, Jason D.