D) Determine if sensor is still useful by following the calibration
procedure given is Section VII.
E) If fault not corrected, return to MMC for repair. Sensor or
integrated circuit chip may require replacement.
PROBLEM NO. 5: Liquid Crystal Display (LCD) does not function properly one or more segments
stay on or off all the time producing strange figures.
PROCEDURE &
EXPLANATION: Display contact may be corroded or dirty. Remove hub cover and associated
P.C. Board by first removing six machine screws. Remove the three push-
button switches and seal boot fasteners. P.C. board and associated display
may now be separated from coverplate. Remove (LCD) display bezel (see DWG.
B-2401-31) by first removing two machine screws and nuts. Carefully lift
bezel and liquid crystal display from blue connector. Make sure that the long
thin elastomer contact strips that fit into the top and bottom horizontals slots
of the connector are not lost. Remove connector with associated contact
strips exposing P.C. Board contacts. Use a good non-oil contact cleaner to
clean P.C. Board contacts. If corroded or dirty, wipe contact (bottom side
only) with cotton swab wetted with alcohol, being careful not to saturate
LCD with fluid.
CAUTION !
Do not spray contact cleaner on LCD display or permanent damage may be
incurred. Re-assemble in reverse order making sure elastomer contact
strips are inserted properly in blue connector horizontal slots. Note that
blue connector bottom pins fit into mating hose on P.C. Board for proper
alignment. If above procedure does not cure problem then either display or
integrated circuit A/D converter is at fault. Spare display can be substituted
to isolate problem. Order from MMC together with new connector.
PROBLEM NO. 6: Display is damaged, permanently discolored broken.
PROCEDURE &
EXPLANATION: Order new display and connector from MMC and follow procedure
given in Problem No. 5 to replace.
PROBLEM NO. 7: Unit operates properly in temperature mode, however, when placed in ullage
mode, horn does not sound in oil or in water, or sound is extremely weak.
PROCEDURE &
EXPLANATION: Sonic sensor has probably been damaged by being dropped and replacement
may be required. Check unit in a container of clean lube oil, and then in a
container of water. If sensor does not respond per operating procedure, then
sensor replacement is probably necessary. Return to factory.
Page 17
To Next Page
