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Quality Control
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Quality Control |
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Qualitative Tests
The gage installation should first be given a close visual inspection. If any discolored or jagged solder joints are observed, these should be re-soldered to achieve smooth, shiny solder deposits. All traces of soldering flux must be completely removed with an appropriate solvent such as M-Line Rosin Solvent . The gage itself should have a uniform color, since discolored areas visible through the backing may indicate voids in the adhesive bond line. If voids exist, the gage output is apt to be unstable when excitation is applied. A further check on bond quality can be made with the gage connected to a strain indicator. Pressing gently on the grid with the eraser end of a lead pencil should produce a small output indication which returns to zero with removal of the pressure. (Note: in performing this test on open-face gages, the pressure should be applied through a teflon strip to protect the grid.) Erratic meter indication or failure of zero-return suggests an incomplete bond, and the gage should be replaced. 
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