SECTION 6 | TROUBLESHOOTING FLOWCHARTS
SECTION 6 | TROUBLESHOOTING FLOWCHARTS
6.4 | LOWER CIRCUIT
Does machine
lower?
Not
at all
Descent speed slow or
erratic?
Are any structural
members bent?
Contact manufacturer to
arrange replacement.
Is there a
restriction in
hydraulic hose?
Yes
Yes
Does the up/
down switch
appear
damaged?
Yes
Creeps down? Or
Goes up and Comes
Back Down?
Has key switch
Or master power
switch been turned
off?
Is an E-Stop
activated?
Is battery
charged?
Is emergency
down valve
open?
Yes
Faulty down
valve?
Electrical problem?
Disconnect coil.
Check if unit stops drifting.
Check voltage at coil
—
should be
0 V when not energized.
Foreign matter
lodged in up or
down valve?
Damaged cylinder or
damaged seal in cylinder?
Run unit up and then check for
oil flow out of return line. Bad
cylinder seal if oil is flowing
from return line.
Down Valve Coil
mounting nut too tight?
Nut should only be lightly
snug: 30 in.-lb.
No
Yes
Faulty check valve
in pump?
Listen carefully near motor
when not energized
—
may be
running backwards
Yes
Starts descending,
then stops?
Is maintenance lock
chock in place?
Yes
Will Manual
Override lower
the platform?
Turn key to
upper or lower
ON position.
Pull out
emergency
stop button at
upper and
lower controls.
No
No
No
Level of skill with
hydraulic maintenance?
Not experienced
with hydraulics
Yes
Yes
Flowchart: HB-1230-Lowering
Troubleshooting Step 3B: Lowering
Troubleshooting Flowcharts--General Notes:
Inspect parts for visible damage as they are encountered.
After each step, check if problem has been indentified and/or resolved.
If so, make the recommended fix or see a referenced document.
If not, continue troubleshooting.
If a part has been identified as needing replacement, see the
Parts View
To identify part number to order.
If any wiring or components have been altered from the original
manufacture, problems may not be identifiable.
WARNING
Any modification on this machine without
the express consent of the manufacturer
is prohibited.
WARNING
Failure to comply with safety precautions
may result in damage, injury, or death.
Refer to Maintenance Manual for
complete warnings
See also
Wiring Diagram
or
Schematic
And
Hydraulic Schematic
WARNING
: Set up for maintenance safety:
Remove load from platform.
Check for overhead obstructions.
Platform movement may occur.
Never Reach between scissors links or prop up
platform unless maintenance pins are in place.
Yes, but
not properly
No
No
Check wiring connections in lowering
components.
See Electrical Schematic
WARNING:
Double check that
maintenance pins are in place or
that platform is all the way down.
Yes
Yes
No
Yes
Charge battery.
See
SD-Battery-01
Yes
No
No
Yes
Level of skill
with hydraulic
maintenance?
Check Hydraulic
Circuit. (Additional
tools required,
higher level of skill
required)
Refer to
Hydraulic
Schematic
Are power
connections to
lowering circuit and
switches functioning
properly?
Replace or repair
identified problem.
See
Parts List
.
Contact
Hy-Brid
Lifts
No
Yes
No
No
No
Experienced with
Hydraulic systems
Experienced
With hydraulic
systems
Not experienced
With hydraulics
Yes
No
Close
emergency
down valve.
Check cable
connections.
Flush down valve by
simultaneously pressing up
switch at base and down
switch on platform control
for 30 sec.
Replace
hydraulic hose
Disassemble and clean.
Look for residue in screen
and on O-ring or damage
to O-ring.
Replace coil
and lightly
tighten nut.
No
Yes or Don’t know
Replace
down valve.
Might be able to repair with seal
kit;, probably need to replace
cylinder. If walls inside cylinder
are scratched or pitted, cylinder
needs replacement.
Yes
Replace
pump.
Replace
down
valve
No
No
Reference Revision A
Reference Revision A
Refer to
Diagnostic
Light Codes in
Maintenance
Manual
What does the
diagnostic LED
show?
Has a velocity fuse
been activated?
No
Yes
Check for hydraulic leak and repair as needed. Reset velocity fuse by elevating platform
w/ hydraulic pump. Check that unit has proper hydraulic fluid. Replace as needed.
ALWAYS remember to use maintenance lock pins when doing any hydraulic work.
Replace rocker
switch at lower
control or joystick
at upper control.
Is maintenance
lock in place?
No
Remove
ML
Chock
Remove
ML
Chock
BY CUSTOM EQUIPMENT LLC
BY CUSTOM EQUIPMENT LLC
36
37
MAINTENANCE & TROUBLESHOOTING
HB-1230
SUPO-729
REV B
MAINTENANCE & TROUBLESHOOTING
HB-1230
SUPO-729
REV B
