From: cybernesto@macgui.com   
      
   > Yes it will run from a generic 9vdc supply, but doesn't keep time   
   > correctly   
   > that way.   
   That's strange. You are sure that it is not a switching power supply?   
      
   I think I have enough spare parts to try the circuit you suggest,   
   > using a 9v (AC) transformer and bridge rectifier. It may need a bit of   
   > additional smoothing in the power supply. I think there's only a 100uf cap   
   > or two in the Cricket! itself.   
   Indeed. 1000uF are actually better.   
      
   > There is a 555 chip as well, and if I hook it up to 14vdc or so it will   
   > keep reasonable time. The speed of the clock seems to fluctuate a bit with   
   > the input voltage. I wondered if it was a backup time base or something.   
   The 555 oscillator is used together with some inductors to generate the -5V   
   required by the speech chip. The frequency is not critical for this   
   application.   
      
   > Based on the regulator it should be ok up to 18 volts but I didn't want to   
   > go that high. There's also a small potentiometer which I suspect may be   
   > related to a secondary time base.   
   The potentiometer is used by the speech chip to set its RC oscillator   
   frequency to about 160kHz.   
      
   > you talked about. I put new electrolytic capacitors in mine so don't   
   > really   
   > want to open it back up again.   
   Good idea. I have two and both stopped working because of some leaky   
   capacitors.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)