MKS Micro-Baratron 870B, Instruction Manual, Page: 56 / 68

Troubleshooting Chapter Five: Maintenance and Troubleshooting
46
Troubleshooting
Troubleshooting Chart
Failure Symptom Possible Cause Solution
Output Signal "Stuck" - no
response from panel.
Transducer will not Zero or Span.
Overrange Positive or Negative
Output signal.
Transducer Sensor Element
internally shorted Perform continuity check on Sensor
Electrodes as follows; Remove the
electronics assembly from the sensor
element. Locate the two electrode pins
on the "top" of the sensor element.
Using an Ohm Meter, check for
resistance between each electrode pin
and the sensor element body. If there
is a reading less than infinity (open)
then the sensor element is internally
shorted and the Transducer must be
replaced. Typical readings for
defective sensors are less than 1000
Ohms, however higher resistances can
still indicate a problem. If no
continuity is present (infinite
resistance) then sensor element is OK,
refer to next possible cause or return
the Transducer to the MKS factory for
service.
Output Signal "Stuck" - no
response from panel.
Transducer will not Zero or Span.
Broken Ground connection
between the PWA and the
Sensor Element. Remove the enclosure and inspect the
three soldered connections where the
PWA is mounted to the "chassis".
One or more of these solder joints may
be broken, or the solder pin may be
broken off the chassis. If either
situation is present the electronics
assembly must be replaced. If not,
refer to next possible cause or return
the Transducer to the MKS factory for
service.
Output Signal "Stuck" - no
response from panel.
Transducer will not Zero or Span.
Overrange Positive or Negative
Output signal.
Internal cable assembly
connecting the PWA to the
I/O connector is loose or
broken. Remove the enclosure and inspect the
internal cable assembly at both ends.
If a loose or broken wire or crimp is
present then the cable assembly must
be replaced.
If not, refer to next
possible cause or return the
Transducer to the MKS factory for
service.
Transducer will not Zero or Span. Factory Coarse Zero
adjustment is not properly
centered. Remove Transducer from service and
return to MKS factory for repair.
Measurement slowly goes
positive over time. Transducer has seen
Overpressure conditions. Remove Transducer from service and
return to MKS factory for repair.