2003/10/01 Caterpillar

Electric Power Generation:

G3520C (S/N: CWW1-UP; CWY1-UP)

SR4 (S/N: 5KA1-UP; 5NA1-UP; 6AA1-UP; 6FA1-UP; 9AB1-UP)

Engine:

3208 (S/N: 29A1-UP; 30A1-UP; 5YF1-UP)

3304 (S/N: 5CA1-UP; 83Z1-UP)

3304B (S/N: DED1-UP; 2KK1-UP; 9HK1-UP)

3306 (S/N: 85Z1-UP)

3306B (S/N: EFA1-UP; B8D1-UP; 1CZ1-UP; 2AJ1-UP; 8JJ1-UP; 8NS1-UP; 9DS1-UP; 9NR1-UP)

3406 (S/N: 75Z1-UP)

3406B (S/N: 2WB1-11475; 4JK1-98; 4PM1-UP; 4RG1-1501)

3406C (S/N: KPS1-UP; PFH1-UP; 1DZ1-UP; 1LS1-UP; 2WB11476-UP; 4JK99-UP; 4RG1502-UP; 4ZR1-UP; 8FS1-UP; 9ES1-UP)

3406E (S/N: 8AZ1-UP; 9NN1-UP)

3408 (S/N: 78Z1-1143)

3408B (S/N: 2BG1-UP; 78Z1144-UP)

3412 (S/N: 1EZ1-UP; 2WJ1-UP; 3FZ1-UP; 4BZ1-UP; 81Z1-14500)

3412C (S/N: BAK1-UP; BAX1-UP; BCW1-UP; 2SZ1-UP; 5FL1-UP; 81Z14501-UP; 9EP1-UP)

3456 (S/N: BGA1-UP; CAH1-UP; CBX1-UP; CCB1-UP; EPE1-UP; GHJ1-UP)

3508 (S/N: CAW1-UP; CNF1-UP; PTK1-UP; 1JZ1-UP; 1ZF1-UP; 23Z1-UP; 3LS1-UP; 5XM1-UP; 5PW1-UP; 70Z1-UP)

3508B (S/N: BGX1-UP; CNB1-UP; PTN1-UP; 1FZ1-UP; 2HW1-UP; 4GM1-UP; 5KW1-UP; 6PN1-UP)

3512 (S/N: CMJ1-UP; FDR1-UP; PTG1-UP; PTH1-UP; 1KZ1-UP; 24Z1-UP; 3MS1-UP; 3WS1-UP; 3YF1-UP; 6PM1-UP; 6WW1-UP; 67Z1-UP)

3512B (S/N: BLF1-UP; BRK1-UP; CMC1-UP; FDE1-UP; PTF1-UP; PTM1-UP; 1GZ1-UP; 4AW1-UP; 5AW1-UP; 6GW1-UP; 6WN1-UP; 8RM1-UP)

3516 (S/N: CAL1-UP; CMD1-UP; 1LZ1-UP; 2TS1-UP; 25Z1-UP; 3JS1-UP; 3NS1-UP; 4XF1-UP; 5SJ1-UP; 6CL1-UP; 7KM1-UP; 73Z1-UP; 8TW1-UP)

3516B (S/N: BMB1-UP; BPJ1-UP; CPA1-UP; FDN1-UP; FDX1-UP; PPS1-UP; 1HZ1-UP; 1NW1-UP; 2JW1-UP; 6HN1-UP; 7RN1-UP; 8NW1-UP)

G3306 (S/N: CNR1-UP)

G3406 (S/N: KAR1-UP)

G3412 (S/N: KAP1-UP)

G3508 (S/N: CPJ1-UP; CPS1-UP; CPY1-UP)

G3512 (S/N: CRN1-UP; CSP1-UP)

G3516 (S/N: CSZ1-UP)

G3516B (S/N: CEY1-UP; CME1-UP; CSC1-UP)

G3520B (S/N: BGW1-UP; CWD1-UP)

Power Module:

PM3412 (S/N: CAJ1-UP)

PM3456 (S/N: B3G1-UP)

PM3508 (S/N: BLM1-UP)

PM3512 (S/N: BNR1-UP; BRF1-UP)

PM3516 (S/N: BPD1-UP; CAC1-UP)

PMG3516 (S/N: CFD1-UP)

Illustration 1	g01025538

Problem Description

An intermittent voltage sensing or an intermittent voltage adjust circuit can lead to above-normal generator output voltage and VR3 voltage regulator failure. An intermittent circuit can be caused by the following:

• Loose terminations

• Improper terminal crimps

• Poor solder joints

Improvement Actions

Terminations

A secure termination can be better assured by placing one 5H-6555 Lockwasher beneath every wire terminal that is used for your specific application. The 5H-6555 Lockwasher must be placed between the voltage regulator terminal pad and the wire terminal. Do NOT place the 5H-6555 Lockwasher directly under the screw. Refer to Illustration 1.

Terminal Crimps

Insulated crimp-on wire terminals should be inspected for proper installation. Visually confirm that the wire insulation is properly stripped and that the crimp is made around bare wire only. No wire insulation should be seen within the crimp area. A gentle pull test will confirm that the terminal is effectively crimped on the wire. Refer to Illustration 1.

Replace the terminal if the terminal is improperly crimped, discolored, or corroded. If the terminal is discolored or corroded, determine and eliminate the root cause of the discoloration or corrosion. To replace the terminal, use a crimp tool and follow the installation process recommended by the terminal manufacturer.

Note: If the wire is found to be damaged, replace the entire wire from termination to termination. In-line splices are NOT recommended.

Use only locking-fork terminals or ring-style terminals. Size the terminals according to the wires on which they will be installed and the size of the screws that will be used. When possible, use non-insulated terminals. Non-insulated terminals give the technician an opportunity to visually inspect the crimp. Use heat shrink tubing to provide insulation and additional strain relief to the termination. When insulating with heat shrink tubing, perform the following steps.

1. Use properly-sized heat shrink tubing.

2. Place the heat shrink tubing on the wire before crimping the terminal. The heat shrink tubing should extend over the wire by 6 mm (0.25 inch) to 13 mm (0.5 inch).

3. To complete the installation, apply a heat source to the tubing until the tubing adheres to the wire.

Solder Joints

Solder joints, especially those on the remote voltage adjust poteniometer(s), must be inspected. The solder deposit should be reasonably uniform. However, uneven areas or depressions on the surface that are clean and smooth are acceptable. A porous or granular appearance, or the appearance of concentric rings within the joint, indicate a poor solder joint that must be repaired.

Melted or burned wire insulation is an indication that excessive heat was applied to the solder joint during the soldering process. Excessive heat applied to the solder joint can also cause internal damage to the remote voltage adjust potentiometer. An intermittent (or otherwise defective) remote voltage adjust potentiometer may cause the VR3 voltage regulator to fail.

If damage is suspected, check the remote voltage adjust potentiometer with an ohmmeter or multimeter in order to verify proper operation. If an improper value is measured or if an intermittent operation is detected, replace the potentiometer (using proper soldering techniques). After the potentiometer has been replaced, check the potentiometer for proper operation.