What was found
(CAN) THE NR 2 GEN CAUTION LIGHT ILLUMINATED ON CAWS PANEL. PILOT ALSO NOTED THAT A VERY LOUD SQUEALING SOUND COULD BE HEARD IN HEADSET. CAUTION LIGHT THEN ILLUMINATED & PILOT THEN SELECTED NR 2 GEN SWITCH TO OFF POS. GEN WAS THEN RE-SELECTED TO ON POS, WITH SAME RESULT AS NOTED ABOVE. GEN #2 WAS THEN SELECTED TO OFF POS, & THEAIRCRA FT RETURNED TO BASE. ONCE AGAIN MAINTENACE FOUND THAT POST SB- "24-016" BRUSHES HAD FAILED WELL BEFORE THEIR LIFE LIMIT WAS REACHED. A EW SET OF POST S/B BRUSHES WAS INSTAND AIRCRAFT GROUND RUN, WITH NO FURTHER DEFECTS BEING NOTED. AS MENTION IN OUR PREVIOUS SDR 11-05-2001. MAINT HAS INSTITUED A VOLUNTARY