What was found
PILOTS REPORTED WHILE IN CRUISE FLIGHT, THE RT GEN OFF-LIGHT ILLUMINATED. ALSO, NOTED THE LT GEN VOLTAGE WAS FLUCTUATING UP TO 30 VOLTS. ATTEMPTS MADE TO BRING RT GEN BACK ON LINE, HOWEVER, IT WOULD NOT STAY ON. PILOTS ELECTED TO TURN RT GEN OFF AND CONTINUE FLIGHT TO HOME BASE. WEATHER AT THE TIME WAS VFR. DISCUSSION REVEALED THE RT GEN VOLTAGE WAS OKAY, BUT LT GEN WAS FLUCTUATING TO AS HIGH AS 30 VOLTS. INSPECTED BOTH SETS OF GEN BRUSHES FOR CONDITION. BOTH SETS OF BRUSHES REPLACED AS PRECAUTIONARY MEASURE. LT GEN CONTROL UNIT REPLACED AS BEING SUSPECT ITEM THAT WOULD CAUSE OVERVOLTAGE CONDITION. TEAR-DOWN REPORT CONFIRMED THE PROBLEM.