Teledyne 4700, Serivce Manual

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4700 Refrigerated Sampler Service Guide
Section 2 Sample Delivery System
2-22
2.6 Distributor
The distributor directs collected liquids to the bottles. Movement
of the distributor is controlled by user-specified program settings.
Drive circuitry For a description of distributor drive circuitry, refer to
Section 4.1.10.
Functional testing and
diags For functional CPU board testing through HyperTerminal, see
Section 4.3.3
Functional Tests . The tests are listed by category in
Table 4-2.
Refer to Section 5.1.6 for standard 4700 distributor diagnostics.
Test points Test Point 2, located on pin 2 of U1 on the CPU (see Figure A-5 in
Appendix A), gives the home output from the distributor stepper
motor driver. This signal will be low when both phases are being
driven at 70.7%.
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.
Tools required for service
5
/
16
" nut driver, #1 and #2 Phillips screwdrivers
2.6.1 Distributor Alignment The 4700’s unique, free-moving distributor is designed to realign
itself before the collection of each sample. This can give the
appearance of arm "drift" or misalignment between samples.
Alignment check To check for proper distributor alignment above each bottle
mouth, first remove the discharge tube (see Figure 2-29). The
tension placed on the distributor arm by the discharge tube can
create the illusion of misalignment.
Enter the bottle number to which the sampler should move the
arm. Press Enter and observe whether or not the arm aligns
properly over the correct bottle.
Calibration If the distributor is truly out of alignment, calibration is
required.
To start the diagnostics from the Main Menu screen:
1. For software versions 1.10 and later, enter the code 82253
(hidden menu code for TABLE) Earlier versions require no
code.
2. Select the
CONFIGURE
option and press Enter.
3. Press the Previous button until the
RUN DIAGNOSTICS
option
is displayed. Press Enter.
4. The sampler displays a diagnostic option. Press Enter to
start the test or press the Next or Previous buttons to
scroll through the diagnostic options.
5. Calibrate the distributor as instructed in Section 5.1.6 Test
Distributor .
6. Upon completion, return to the standby screen (
PRO
-
GRAM
/
CONFIGURE
) and re-enter the code 82253 to exit cali-
bration mode.
PROGRAM CONFIGURE
VIEW LOG
SELECT OPTION: (<-->)
RUN DIAGNOSTICS
SELECT DIAG: (<-->)
TEST 'RAM'