FREQUENCY METER - TROUBLE SHOOTING
NOTE: Make all checks using ohmmeter. Engine should be "off" and ignition key should be "off", except as noted.
PROBLEM
POSSIBLE CAUSE
SOLUTION
Meter registers exceptionally low.
Line fuse may be blown.
Replace fuse in line under instrument
panel (1 amp).
Power wires may be disconnected.
Check and correct. (Key "on" for this
check.)
Meter assembly may not be working
Replace meter assembly - not field
properly.
repairable.
Meter does not register.
Line fuse may be blown.
Replace fuse - see above.
Power wires may be disconnected.
Check and correct. Be sure red wire is
properly grounded. (Key "on" for this
check.)
Coupling for magnetic pickup gear
Remove cover by prying. Try to rotate
may be damaged.
gear by hand. If gear rotates, coupling
is damaged. Replace roll pin.
Gap between magnetic pickup and
Adjust gap. Proper gap is .030".
gear may not be correct.
Tighten jam nut.
Also clean any
residue from around gear.
Electric continuity between magnetic
Under instrument panel, check across
pickup and meter may be broken.
black and white wires from magnetic
pickup, with ohmmeter probes. (Use
needle probes or pointed objects to
penetrate wire installation.)
- A reading of approximately 100
ohms indicates continuity is good.
- A reading of much higher than 100
ohms indicates an open circuit.
If resistance reading indicates an open
circuit,
remove
connector from
magnetic pickup and shunt the two
contacts in the connector with a short
piece of wire.
Again read the
resistance across the black and white
wires.
- A reading of approximately 0 ohms
indicates wire assembly is good, but
magnetic pickup needs replacing.
Replace pickup.
- A reading of very high resistance
indicates wire assembly has a break.
Replace
connector
and
cord
assembly.
Meter assembly may be damaged.
If system has checked out good to this
point, problem is probably in the meter
assembly.
Install new meter
assembly, as this is not field
repairable.
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