CYLINDER 7Y0681 - Caterpillar

Engine: 3306B (S/N: B8D1-UP; 8NS1-UP) 3408C (S/N: TAM1-UP) 3412 (S/N: 4BZ1-UP; 2WJ1-UP) 3412C (S/N: DJN1-UP; 9EP1-UP; RLR1-UP; TFT1-UP; BCW1-UP; LRY1-UP) 3412E (S/N: TGC1-UP) 3508 (S/N: CNF1-UP; 70Z1-UP) 3508B (S/N: CNB1-UP; S2B1-UP; 3DM1-UP) 3512 (S/N: 81Z1-UP; 25Z1-UP; CMJ1-UP; 67Z1-UP) 3512B (S/N: CMC1-UP; S2H1-UP) 3516 (S/N: CMD1-UP) 3516B (S/N: FDN1-UP; 7RN1-UP; S2R1-UP; GZS1-UP; BPJ1-UP; PBR1-UP; PPS1-UP) G3306 (S/N: JCA1-UP) G3406 (S/N: R7E1-UP; KAR1-UP) G3408 (S/N: 6NB1-UP; 6RJ1-UP) G3408C (S/N: BAZ1-UP) G3412 (S/N: R7A1-UP; 7DB1-UP; KAP1-UP) G3516 (S/N: ZBA1-UP; CSZ1-UP; 4EK1-UP) C-15 IND (S/N: BEM1-UP) C18 MARINE (S/N: C1J1-UP) G3516B (S/N: ZBC1-UP) G3520C (S/N: CWY1-UP)Power Module: PM3456 (S/N: B3G1-UP) PM3412C (S/N: 5FL1-UP) PM3412 (S/N: CAJ1-UP) PM3508 (S/N: BLM1-UP) PM3512 (S/N: BRF1-UP) PM3516 (S/N: BPD1-UP)Generator Set: 3406C GEN SET (S/N: C2G1-UP; KPS1-UP; 9ES1-UP; LRX1-UP) 3406C MARINE GS (S/N: PFH1-UP) 3406E GEN SET (S/N: 8AZ1-UP) 3456 GEN SET (S/N: CCB1-UP; CAH1-UP; GHJ1-UP; CBX1-UP)Introduction
Technical Information Bulletin replaces the 3November 2005 TIB "Genset VR6 Voltage Regulator Part Number 202-8634". Disregard the 3November 2005 TIB. Refer to the following information.The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
Certain VR6 and K65-12B voltage regulators, Part Numbers 202-8634, 219-4078, 219-4079 219-4080 and 219-4081, may fail in a mode that could result in the generator output voltage increasing suddenly, unexpectedly, and for a sustained time period.A complete loss of electric power to connected electrical loads may occur as a result of:
Generator sets and electrical distribution systems being equipped with and employing over voltage protective devices and design schemes
Damage to the generator set excitation system caused by over voltage and overheating, especially during sustained over voltage conditions
Damage to electrical distribution system components such as wiring insulation, transformers, motors and motor controllers caused by over voltage and overheating, especially during sustained over voltage conditions.Sensitive electronic equipment such as, but not limited to, computers and microprocessor-based appliances may be damaged due to over voltage conditions.In some cases, over voltage conditions may produce fire.To determine whether a VR6 or K65-12B voltage regulator is affected, locate the serial number on the bar-coded film that is located on the regulator component side. VR6 voltage regulators with serial numbers between E00363510 and E00458010 inclusive or H00363510 and H00458010 inclusive are affected.K65-12B voltage regulators with serial numbers between H00357127 and H00458248 inclusive are affected.Symptoms of this problem are listed below:
The failure mode may be accelerated in extreme temperature and/or vibration conditions.
The failure mode may be presented intermittently or continuously.
Certain VR6 and K65-12B voltage regulators used in three phase sensing applications may cause the generator output voltage to increase 20%.
Certain VR6 and K65-12B voltage regulators used in single phase sensing applications may cause the generator output voltage to increase 40%.The root cause has been determined to be contaminated leads on an internal sensing circuit component, which may allow intermittent, less-than-optimized solder joints on that component.VR6 and K65-12B voltage regulators manufactured on or after 17November 2004 are not affected.Proper voltage regulator operation is dependent upon the electrical connections to and from