Model 4342A
Section TTT
Figure 3-6
Mechanical zero adiustment
The meter is properly zero-set when the pointer sets exactly over
the zero calibration scale mark and the instrument is in its normal
operating environment. To check the meter mechanical zero, turn the
instrument off and allow 30 seconds to completely deenergizethe z
strument. To obtain maximum accuracy and mechanical stability, if
the meter is not over zero, zero-set the meter as follows:
a. Rotate meter pointer adjustment screw @ clockwise until meter
is moving toward zero in an upscale direction.
b. Continue rotating screw clockwise and stop when pointer is
exactly at zero. If the pointer overshoots, continue rotating
the adjustment screw clockwise to do steps a and b once again.
C. When the pointer is exactly over zero, rotate adjustment screw
slightly counterclockwise to relieve tension on pointer suspen-
sion. If pointer moves off zero, repeat steps a, b and c, but
rotate less counterclockwise.
Electrical zero adiustment
The meter pointer should set exactly over the zero scale mark when instrument is
turned on and nothing is connected to measurement terminals. Turn the instru-
ment on and allow at least 15 minuts warm-up time to let the instrument reach a
stable operating condition. If meter pointer is not over zero, zero-set the
meter as follows:
a. Set FREQUENCY RANGE selector @to 22k - 70k (10k - 32k for Option
001) and Q RANGE@ to 1000.
b. Adjust rear panel METER ZERO ADJ control@ so that the meter
pointer is exactly over zero.
Figure 3-6. Zeroing Procedure (sheet 2 of 2).
3-9 |