Teledyne 2120 - Trace Nitrogen in Argon Analyzer - Manual (Page 59)

Trace Nitrogen in Argon Analyzer Maintenance
setting on the potentiometer. For example, if the reference
voltage measures 1.223 VDC and the plate voltage
setting is 3.14, then the expected control voltage is:
0.314 x 1.223 VDC = 0.384 VDC
If not, the plate voltage adjustment potentiometer is at fault.
If the control voltage measures correctly, remove the PMT
from the socket (refer to section 5.4.6). Measure the voltage
between pins 11 and 10 in the socket, with pin 10 being
ground. You should measure 1000x the control voltage. Using
the example above, you would measure 384 VDC. If you do
not, the power supply is at fault and should be replaced.
5.4.11 Low Voltage DC Supply Board
The low voltage DC power supply comes from the 255 Hz power
supply board. Output is set at +15 VDC and -15 VDC + 0.8 VDC at the
time of installation. Check this by measuring the voltage at the test point
panel across the green (-) to red (+) +15 VDC test jack and the green (-)
to orange (+) -15 VDC test jacks.
5.4.12 Regulated 255 Hz Power Supply
The regulated 255 Hz power supply output is set at 85 ± 5
VAC at the time of installation. Check this by measuring the voltage
at the test point panel across the blue 90 VAC test jacks.
5.4.13 Digital Panel Meter
To replace the DPM, use the following procedure:
1. Remove the AC power cord from the analyzer.
2. Remove the analyzer cover.
3. Remove the DPM mounting bracket screws.
4. Loosen the terminal connections on the back of the DPM,
noting the connections for installation of the new meter.
5. Remove the DPM by sliding it out through the front panel of
the analyzer.
6. Replace the DPM, and re-connect the terminal strip wiring.
Teledyne Analytical Instruments
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