Metal Samples MS2500L, Operator'S Manual

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D. Visual Inspection
Carefully separate the boards and inspect the two circuit boards for:
• Signs of overheating or overheated components.
• Short circuits caused by foreign debris.
• Broken or cracked solder traces.
• Corrosion on connector surfaces.
• General corrosion attack to boards or components in general.
• Signs of moisture damage or condensation.
• Tampering or abuse.
Inspect all cable connections and connectors for integrity. If necessary, use a DVM set to read ohms or
continuity to test cables and connectors.
E. Electrical Testing
Carefully reassemble the two circuit cards. For testing or calibration purposes, the instrument can be
operated without the electrostatic shield. However, it is necessary to replace the two screws used to
secure the upper part of the shield. These two points are used for board interconnection of the instru-
ment ground. It will also be necessary to temporarily replace the two control knobs by tightening only
the two set screws used to bind the flat parts of the switch posts.
Connect the spare cable assembly to the connector on the A1 Board. Note that the cable shield need
not be connected for testing purposes. Place a 10 MPY prover on the cable connector. With the power
supply turned off, connect the power supply and the current reading DVM to the A2 Board connector
observing proper polarity. Set the mode of operation to LPR and the output mode to SAMPLE. (Refer
to the labeling on the electrostatic shield). Set the SAMPLE TIME to 00.1 minutes. Turn on the power
supply and observe the current. If the unit functions properly, the current reading should settle out to
5.6mA (± 0.1mA) after 2 to 3 polarization cycles. If the unit malfunctions, one or more of the following
symptoms will appear: