Ludlum Measurements 177, Руководство пользователя

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Model 177
Technical Manual
Section 7
Ludlum Measurements, Inc. Page 7-2 October 2018
SYMPTOM
Non-linear Readings
POSSIBLE SOLUTION
1. Check the high voltage (HV) by
pressing the
HV TEST
button. If a
Multimeter is used to check the HV,
ensure that one with high impedance
is used; as a standard multimeter
could be damaged in this process.
2. Check for noise in the detector cable
by disconnecting the detector and
placing the instrument on the lowest
range setting. Wiggle the cable and
observe the reading for significant
changes.
3. Check for “sticky” meter movement.
Does the reading change when you
tap the meter? Does the meter needle
“stick” at any spot?
4. Check the “meter zero.” Turn the
power
OFF
. The meter should come
to rest on “0.”
Meter goes full-scale
or “pegs out”
1. Replace the detector cable to see if it
has failed, causing excess noise.
2. Check the HV and, if possible, the
input threshold for proper setting.
3. Check for loose wires, especially
between the main board and the
calibration board.
Troubleshooting GM Detectors
1. If the tube has a thin mica window, check for window breakage.
If damage is evident, the tube must be replaced.