BOOM TMS700E SERVICE MANUAL
4-16 Published 01-29-2015, Control # 512-01
section at a given length, oil is trapped in the cylinder by the
holding valve. Refer to Hydraulic Remote Control Valve,
page 2-34 for a complete description of the holding valve.
Theory of Operation
Flow from the pump travels to the telescope directional
control valve. Movement of the control lever for telescope
functions from neutral sends a pilot pressure signal to the
directional control valve to shift the spool in the directional
control valve. This aligns the appropriate passages in the
control valve to route oil to the telescope cylinders.
Also refer to Theory of Operation, page 4-1 in this Section.
Maintenance
Troubleshooting
SYMPTOM PROBABLE CAUSE SOLUTION
1. Erratic operation of
extending
telescoping
cylinder.
a. Low hydraulic oil level. a. Check for leaks. Repair any found.
Replenish hydraulic oil to proper level.
b. Damaged relief valves. b. Repair or replace relief valves.
c. Air in telescope cylinder. c. Bleed by lowering telescope cylinder
below horizontal.
d. Low engine rpm. d. Increase engine rpm to proper setting.
e. Lack of lubrication on boom sections. e. Properly lubricate all boom sections.
f. Extremely tight boom extension
sheaves.
f. Inspect and properly lubricate boom
extension sheaves.
g. Improper boom alignment caused from
side loading.
g. Reduce and properly hoist load.
h. Worn boom wear pads. h. Replace wear pads and properly
lubricate.
i. Distorted boom section. i. Replace distorted section.
j. Damaged telescope cylinder. j. Repair or replace cylinder.
k. Clogged, broken, or loose hydraulic
lines or fittings.
k. Clean, tighten, or replace lines or
fittings.
l. Damaged control valve. l. Repair or replace control valve.
Reference Only
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