OHAUS valor 5000 series, Service Manual

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CHAPTER 2 DIAGNOSTIC GUIDE
2.1 TROUBLESHOOTING
This section of the manual contains troubleshooting information. Information is contained to
isolate specific problems using Table 2-1, Diagnostic Guide. Follow all directions step by step.
Make certain that the work area is clean. Handle scale components with care. Use appropriate
Electro-Static Device.
2.2 DIAGNOSTIC GUIDE
Table 2-1 is a Diagnostic Guide designed to help locate the problem area quickly and easily.
The probable causes are listed with the most common cause first. If the first remedy does not
fix the problem, proceed to the next remedy. Before attempting to repair the scale, read all
chapters of this manual to be familiar with the scale components and operation.
2.2.1 Diagnosis
1. Isolate and identify the symptom
2. Refer to Table 2-1, Diagnostic Guide and locate the symptom.
3. Follow the suggested remedies in the order they appear.
4. Perform the indicated checks, or see the appropriate section of the manual.
5. Repair or replace the defective section of the scale.
Note: If more than one symptom is observed, approach one area at a time,
and remember that the symptoms may be interrelated.
If there is a problem that is not covered in this manual, contact Ohaus for further information.
2.2.2 Testing the Membrane Switch
If the scale does not turn on, or menus cannot be accessed, the Membrane Switch may be
defective. It can be tested after removing the Top Housing. (See Section 3.1.)
1. Using an Ohmmeter, measure the resistance between pin 5 and each other pin on
the Membrane Switch Cable. (See Figure 2-2, next page.) The readings should be
infinite resistance.
2. Press each button and check that the resistance is under 50 ohms for each button.
3. Check that the Membrane Switch is not shorted to the Top Housing case.
Check pins 1 through 5 to the case, which should be infinite resistance.
4. If any test fails, the Membrane Switch is defective. Replace it. (See Section 3.5.)
Figure 2-1. Membrane Switch Cable connections.
Valor™ 5000 Series Service Manual 2-1 Ohaus Corporation www.ohaus.com