Global Specialties PB-503C - Manual - Manual (Page 13)

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the low (logic "0") position. Move each switch between its high and low position to verify
proper functioning. Switch the logic switch +5/+V high level switch to +V and the logic
indicator +5/+V operating voltage switch to +V; the relationship between the switch
positions and the logic indicator display should remain the same, regardless of the
setting of the 1.3 - 15 volts +V supply.
By using an ohmmeter, you can check the potentiometers. To do so, select an
appropriate range for measuring 10 K
Ω and connect the ohmmeter leads to R1-1 and
R1-2. With R1 rotated fully counterclockwise a reading of 0
Ω ohms should be observed.
As the potentiometer is rotated clockwise, the resistance reading will be seen to
increase linearly up to 10 K
Ω ± 20%. Now move the ohmmeter lead from R1-l to R1-3;
with R1 fully clockwise the ohmmeter will read zero ohms, and the resistance will
increase linearly to the full value noted previously as the potentiometer is rotated
counterclockwise. Select an ohmmeter range appropriate for 1 K
Ω and repeat these
steps on R2 to verify its function.
To test SPDT switch S9, put S9 in the up position and connect an ohmmeter to S9-1
and S9-2. The ohmmeter should read 0
Ω. When the switch is brought to the down
position, an open circuit should be indicated. Move the ohmmeter lead from S9-1 to S9-
3 and observe a short circuit with S9 down, and an open with S9 up. These steps can
be repeated on S10 to test its functions.