Section 2 Sample Delivery System; Pump - Teledyne 4700 Serivce Manual

4700 Refrigerated Sampler
Service Guide

Section 2 Sample Delivery System

2.1 Pump

General pump information
Functional testing and
diags
Test points
Liquid Present .75V
No Liquid Present 0V
To produce accurate and repeatable samples, the pump uses a
pump revolution counter and patented
detector. The 4700 uses a peristaltic pump housed in a separate,
easily serviceable and fully replaceable module.
This sampler has a high performance pump. As with all such
pumps, it relies upon liquid to cool working components. If the
sampler is programmed to pump in the absence of liquid in
excess of 5 minutes, excessive heat buildup may damage the
paddles, rollers, and housing. Ensure that the liquid inlet is
completely immersed.
Complete technical specifications for the 4700 pump can be found
in Section 1.2, Table 1-1. For general pump maintenance, refer to
Sections 1.4.1 through 1.4.5. For a description of detector and
pump drive circuitry, refer to Sections 4.1.7 and 4.1.12. For com-
ponent part numbers, refer to Table 2-1 on page 2-4.
For functional CPU board testing through Hyper Terminal, see
Section 4.3.3 Functional Tests. The tests are listed by category in
Table 4-2.
Refer to Section 5.1.5 for standard 4700 pump diagnostics.
Hidden menu tests are listed in Section 5.2.
For a complete list of 4700 test points and values, refer to
Section 4.2. Test points are also highlighted in red on the CPU
schematic in Figure A-5, Appendix A.
Test Point 3, located on pin 5 of U10 on the CPU, gives the fil-
tered AC signal from the liquid detector.
Test Point 4 is the liquid detector rectified A to D signal, or the
input to CR23. When liquid is present, this value should be
greater than 0.75V, as shown at left.
1. United States patent 5,125,801
1
non-contacting liquid
CAUTION
2-1