The rectifier or controller changes the AC generated in the alternator into DC voltage used in the on-board power supply (12V) and keeps the current within a specific tolerance range. This ensures the battery remains charged and that light bulbs, for instance, do not burn out. Because this component is exposed to very high temperatures, it is prone to failure. If the rectifier or regulator is damaged or the battery is constantly empty, certain ignition systems stop working, light bulbs burn out continuously or the lights flicker. Yamaha OEM-No. for comparison purposes: 3TJ819600000, 3TJ819600100 replaced by: 3TJ-81960-02-00 on some models there are 2 different controllers - please check the connector before ordering and compare with the image. Also fits: TT600R 5CH 600 cc from 1997 XT600E 4PT 600cc from 1997-2002 XG250 TRICKER 4D6 250 cc from 2005-2006 TW225E 5VC 225cc 2002 FZ400RR 3TJ 400 cc YOM 1990 TDM850 4CF 850 CC YOM. 1991 TDM850 4CF 850 CC YOM. 1991-1992 XJ600S 4CF 600 cc YOM. 1992-1995 XJ600N 4PT 600 cc YOM. 1993-1996