3-1
CHAPTER 3 SCALE TESTING AND CALIBRATION
3. TESTING AND CALIBRATION
This section of the manual contains testing procedures of the individual replaceable components and the
scale. Before and after servicing the EC Series Scales, an operational test and various performance tests
should be made to ascertain whether or not the scale meets specifications.
3.1 TESTING THE AC ADAPTER
The AC Adapters are available with different input voltages. Before testing the Adapter, make sure the
Adapter rating agrees with the power source being used. All Adapters are rated with an output of 12 V dc
at 800mA. Adapters can fail by having shorted internal windings producing low voltage output or no
output at all.
1. Plug the AC Adapter in a suitable power source and measure the open circuit voltage on connector
it should be 10 V dc to 16 V dc.
2. Refer to Section 4.1 and remove the Top Housing. Plug the AC Adapter into the scale and
measure the voltage on the battery terminals. Turn the scale on. The voltage should be 6.5 Volts
dc minimum, and 7.5 Volts dc maximum. If the voltage is below or above these readings, replace
the Adapter. This is the actual battery voltage while charging.
3.2 TESTING THE MEMBRANE SWITCH
The Membrane Switch can be tested after removing the Top Housing from the Bottom Housing.
1. Refer to Section 4.1 and remove the Top Housing.
2. Disconnect the Membrane Switch connector from the Display PCB.
3. Refer to Table 3-1. Using an Ohmmeter, measure the resistance between the pins shown in the
table. The readings should be less than 70 Ohms for each button. If continuity is not present or
the resistance is higher than 100 Ohms, the Membrane Switch is defective. Replace the Membrane
Switch. Figure 3-1 illustrates the cable connector and pin locations.
4. Reassemble Top Housing to Bottom Housing.
TABLE 3-1. MEMBRANE SWITCH PIN CONNECTIONS.
PANEL BUTTON
PINS
SAMPLE
8 to 3
TARE
9 to 3
M+
6 to1
PT
7 to 1
APW
6 to 2
ZERO
7 to 2
•
9 to 5
C
9 to 4
0
9 to 2
1
8 to 2
2
8 to 5
3
8 to 4
4
7 to 5
5
7 to 4
6
7 to 3
7
6 to 5
8
6 to 4
9
6 to 3
Figure 3-1. Membrane Switch Connector.
Summary of Contents for EC Series
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Page 56: ...PN 80010584 B SERVICE MANUAL EC SERIES SCALES 80010584...
