STT113 TOWER CRANE OPERATION AND SERVICE MANUAL
6B
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6) positive turn and negative turn contactor(RD or RG) don’t close.
First, check the connection whether loosen or broken line; next supply power and
check the sliding end of potentiometer RP should have plus minus constant voltage
(when the handle operate), if have no voltage output, lookup potentiometer both
end point should have plus minus constant voltage, if there isn’t voltage input, the
controller have problem. When above check normal, need check RD or A
1
end of
RG contactor should have 48V voltage under the operate handle condition and
farther check the controller have 48V voltage, above check normal, please
replacing the slewing controller.
7) Slewing controller and crystal break tube both burn and turn black, please check
the modular first then check the power supply voltage whether overtop. Please
replacing the slewing controller if above check all normal.
