Model 755A

Instruction Manual

245364-V May 2002

 

R13

C1

U2

 

Voltmeter Lead

R9

Figure 6-3. Detector Adjustment

6-4 SOURCE LAMP REPLACEMENT

1.Remove the four screws securing the detector assembly cover plate.

2.Refer to Figure 6-1 on page 6-4. Carefully remove the small rubber hose connected from the detector/magnet assembly to the detector.

3.If retaining set screw for lamp is accessible, proceed to step 6. If the set screw is not accessible continue to step 4.

4.Remove the two screws holding the optical bench assembly/detector assembly to the magnet assembly. Carefully remove optical bench and detector assembly.

5.Remove the two lock screws (2-56 X 5/16 pan head) holding the photocell in the optical bench. Carefully remove photocell.

6.Loosen lamp retaining set screw, remove lamp.

7.Note location of lamp wires in connector J12. Disconnect leads of lamp assembly from connector J12, Figure 6-2A on page 6-4, using method shown in Figure 6-2C on page 6-4.

Depending on date of manufacture of the analyzer, the original lamp assembly may be either of two types:

Old style lamp assembly with four color coded leads: Red, blue, brown and yellow.

Red

Blue

Brown

Yellow

New style lamp assembly with two leads color coded either both red or both black.

Two Red or

Two Black Leads

8.The replacement lamp assembly is the new style with two leads. On J12, insert one lead into the position formerly used for the brown lead to the old style lamp and the other lead into the position for the blue lead of the old lamp. See Figure 6-2A on page 6-4

9.Insert the lamp into the assembly. After reassembly and application of power, the lamp will have to be rotated to place the lamp filaments in proper orientation.

If the lamp assembly removed from the instrument has two wires, proceed to step 13.

Rosemount Analytical Inc. A Division of Emerson Process Management

Service and Maintenance

6-5