Advanced Instruments 4C3, User Manual

Page: 81 / 139

Descriptions of the TEST menu items and instructions for their use fol-
low:
1. A/D Tests
This set of tests may be used to test the block probe, the cooling
assembly and the sample probe. The A/D tests may also be used
to check the accuracy of the A/D conversion channel or to monitor
the A/D channel for drift over time or temperature (by temporarily
replacing the sample probe with a precision resistor).
On entry, “[START] Ready?” is displayed. Pipet or measure
2-mL of -600 m°C standard into a sample tube and place the tube in
the first position in a cassette. Place the cassette in the left (input)
deck and press the START button.
When START is pressed, the A/D tests display the target cooling
block temperature, the channel being read and the current channel
reading or duty cycle. The display is in the form, “off Blk NNNN.
NN ohm” , where “off” indicates that a target temperature has not
yet been selected, “Blk” indicates that the block probe channel
is being tested, “NNNN.NN” is a
numeric readout of the probe
(or resistor substituted for the
probe), and “ohm” indicates the
units of the readout. These read-
ings are updated continuously.
Pressing the < button sequen-
tially changes the target cooling
well block temperature from
“off” to “+1” , to “-8” , to
“off” , etc.
Pressing the > button sequential-
ly changes the channel and read-
out units from block probe resis-
tance in ohms, to sample probe
resistance in ohms, to block
59
Troubleshooting & Service
0. Select Test Item
1. A/D Tests
2. Stir/Freeze Test
3. Probe Bin Test
4. Serial Loop Test
5. Display/Print Test
6. Beeper Test
7. Keypad Test
8. Head Up/Down Test
9. Cassette Index Test
10. Cassette Pusher Test
11. Head Rotation Test
12. Tube Transport Test
Test Mode Options
Table 6: Test Mode Options