My 1978 TR182 has an electrical flicker that seems to be caused by the powerpack cycling during flight.  Maintenance tells me the cycling is normal but the flicker is not.  The flicker causes the red high voltage light to blink and the alternator needle to momentarily fully deflect to discharge.  The plane has no charging problems and runs fine otherwise.  A volt meter does not show a voltage drop when the flicker occurs.  The powerpack was recently rebuilt.  We thought the system may have a bad diode somewhere.  Thought, help or suggestions?