Zero And Span Potentiometers - Teledyne 2120 Operating Instructions Manual

Maintenance

5.4.14 Zero and Span Potentiometers

The zero and span potentiometers are located underneath the
chassis next to the DPM (refer to Figure 1.3). Perform the following
steps to replace the potentiometer:
1. Remove the AC power cord from the analyzer, and remove the
cover for access to the zero and span potentiometers.
2. Unsolder the potentiometers to be replaced.
3. You will need two tools for removing the potentiometers: an
Allen wrench for the set screw and a small double-ended
screwdriver for the potentiometers base:
a. Loosen the set screw in potentiometer cover with the Allen
wrench, and remove the potentiometer cover.
b. Loosen the potentiometer base with the screwdriver, and
remove it.
c. Pull the potentiometer through the inside of the analyzer to
remove.
4. Install the new potentiometer. Placement of the potentiometer
components during installation will impact the range indication
of the potentiometer. When installing the base, ensure that the
white "tick mark" on the base remains on top. Turn the knob
underneath the potentiometer cover fully counterclockwise
before installing the cover. Adjust the potentiometer to a full
zero reading before tightening the set screw.
5. Resolder the potentiometer.
Teledyne Analytical Instruments
50
Model 2120