26
Section 4
Model 763A Gage Pressure Transmitter
Troubleshooting
!
WARNING: Except for replacing O-rings, fasteners, or connector as-
semblies, no
repair or component replacement on the Model 763A
is authorized.
Unauthorized repairs void any
to
reports for design basis event performance.
Table 4.3—Troubleshooting
Problem
Possible
Source
Probable Cause
Corrective Action
No Output
Power Source
Blown fuse, faulty
component
Replace fuse, repair power
supply
Transmission
Cable
Loose terminal connection
Tighten terminal connection;
locate and replace broken wire
Receiver (or
load)
Blown fuse, faulty component Replace fuse; repair or replace
receiver or load
Transmitter
Loose terminal, reversed
power connection, faulty
component
Tighten terminal, reverse power
connection, return to factory for
repair
Transmitter
"zeros" but
cannot get
full output
Power Source
Low voltage
Repair power source
Load Resis-
tance
Resistance too high
Replace load resistance or
repair as required
Transmission
Cable
Resistance or length of cable
in excess of
Measure cable loop resistance
Electronic
Module
Loss of gain
Return to factory for repair
Range Selector Wrong connection or terminal
resistance increased
Check circuit and operating
procedure for range selector;
clean and tighten terminal con-
nections
Strain Gage
Beam
Physical damage
Return to factory for repair
Pressure Line
valve
Determine source by closing
valves and monitoring for pres-
sure decay
Out of
Calibration
Electronic
Component shifted
Return to factory for repair
Erratic
Operation
Terminal
Connections
Loose or dirty
Tighten and/or clean as required
Electronic
Component
Intermittent
Check connector assembly -
a complete assembly only, any
other repair requires factory
service
Mechanical
Component
Switch not properly adjusted
Check and tighten all process
and mechanical connections
Strain Gages
Physical damage
Return to factory for repair
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