Chapter 7 Servicing
7-4
NOTE
: Power should be removed from the instrument before any servicing is
performed.
IR SOURCE REPLACEMENT
Equipment required:
New IR Source (Part No. 7361)
Screwdriver
1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for
more information.
2. Disconnect power and remove cover.
3. Disconnect IR Source cable from IR Source cover (see Figure 7-3).
4. Remove the two screws holding the IR Source cover to the motor plate. Remove the
IR Source cover.
5. Loosen both clamp screws from brass standoff, remove IR Source.
6. Install new IR Source by following the above procedure in reverse.
7. Re-install the instrument cover.
CORRELATION WHEEL REPLACEMENT
Equipment required:
New Correlation Filter Wheel (Part No. 7358)
Allen Wrench - 5/32" and 5/64"
1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for
more information.
2. Disconnect power and remove cover.
3. Remove the chopper assembly by removing the three Allen head screws holding the
motor mount to the optical bench (see Figure 7-3).
4. Loosen the set screw holding the correlation wheel to the motor shaft. Note that
there is an access hole in the bottom of the motor plate.
5. Carefully pry the correlation wheel off of the motor shaft.
6. Install new correlation wheel by following the above procedure in reverse. Make
sure that the set screw seats on the flat of the motor shaft.
7. Re-install the instrument cover.
8. Let the Model 48C sample zero air for about 90 minutes.
9. From the Service Mode menu, select Initial S/R Ratio, which should be between 1.14
and 1.18. Set the Init Zero ratio to match the Current ratio and press
ENTER
.
10. Calibrate the instrument.
Summary of Contents for 48C
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Page 27: ...Chapter 3 Operation 3 3 Figure 3 2 Flowchart of Menu Driven Software ...
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Page 123: ...Chapter 7 Servicing 7 3 Figure 7 2 Model 48C Component Layout 48P737 ...
Page 125: ...Chapter 7 Servicing 7 5 Figure 7 3 Optical Bench Exploded View 42P761 ...
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Page 146: ...Chapter 9 Optional Equipment 9 2 Figure 9 2 Model 48C Dimensional Outline D42P725 ...
Page 155: ...Chapter 9 Optional Equipment Figure 9 8 Purge Housing Assembly 9 11 ...
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Page 178: ...Appendix B RS 232 Commands B 20 µ ...
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Page 201: ...APPENDIX D PUMP MAINTENANCE ...
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