7
3A. SPAN ADJUSTMENT: Apply an input signal with a frequency equal to the
rated full-scale output of the transducer. Then adjust the Coarse and
Fine SPAN controls to produce a readout on the indicator of the value de-
termined in Step 2A, above--that is, of the full-scale transducer output
in terms of the desired unit of measurement (e.g., 728.2 cfm).
4A. TRIGGER LEVEL ADJUSTMENT: as in Step 4, above.
IV. Verification of Normal Operation
If the Model 3140A is suspected of faulty operation, you should do the fol-
lowing:
1.
2.
3.
If the unit is TOTALLY INOPERATIONAL (front-panel LED indicator does not
light), first check the primary power fuse (F1) located on the standup
board which forms the power-cord connection point. If this fuse is blown,
replace it with a 0.50-amp fuse ("F" version, 0.125-amp but not before
determining the cause of overload (inspect the input power connections for
any short-circuiting, etc.).
Push the front-panel CAL button, and observe the analog output. If it is
stable, noise-free, and adjustable via the Coarse and Fine SPAN controls,
then you can assume that all circuits--with the exception of the front-end
amplifier and trigger circuits--are functioning normally.
To check the front-end circuitry, replace the transducer and cable with a
transducer and cable known to be in good condition and operating reliably.
If the 3140A works properly with this different input source, then the
problem most likely lies in the original transducer/cable. However, if
the observed malfunction persists after this substitution, repairs to the
3140A are probably indicated.
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General