Rice Lake DeckHand/DeckHand Rough-n-Ready System - Manual (Page 11)

Service Information 7
3.3 Load Cell Replacement
Disassembly
1. Remove the four locknuts and washers that secure the platform to load cell channels. Lift off the platform.
Remove the column back plate to gain access to the j-box.
2. Determine which load cell is defective. Use a hardened hex-drive bit and large ratchet wrench to remove
the four hex-drive countersunk machine screws holding the channel to the defective load cell underneath.
Lift off the channel and the spacer on top of the load cell. Note how the load cell cable is routed on its cable
hold downs.
3. Cut the plastic tie at each hold-down to free the cable. Remove the load cell wires from the load cell
terminal in the J-box. Loosen the cord grip and pull the cable out of the J-box. Unwind the excess cable
from the cable-storage studs and pull it out of the mast cavity.
4. Turn the scale on its side to remove the lower load cell screws. With the hex-drive bit and ratchet wrench,
remove the four cap screws and lock washers that hold the cell to the mounting plate. Lift off the cell and
spacer plate beneath.
Reassembly
Tilt and block the scale base enough to have comfortable access to the load cell screws from underneath the base.
Position the new load cell with the cable to the inside and the label readable from the outside. Be sure the load cell
body is not contacting the overload stop screw. Back the screw off if necessary (it was secured with Loctite at the
factory and will turn hard).
1. Set the spacer block and load cell into position. Insert the four load cell screws from the bottom finger-tight
only; final adjustments in load cell position are necessary before the screws are torqued down.
2. Run the new load cell cable to the J-box using exactly the path dictated by the cable existing ties. The
existing cable hold downs keep the cables under the middle of each load cell channel, where they are
protected from accidental crimping between the flexing channels and the frame. When new cable ties are
attached, feed the cable through the cutout in the frame and into the mast cavity. Do not shorten the load
cell cable; it is temperature-compensated for the supplied cable length. Wind the excess cable around the
cable-storage studs, leaving enough free to wire into the junction box.
3. With the load cell still loose enough for final adjustment, set the top spacer block and load cell channel on
the cell and insert the self-centering countersunk load cell screws. Tighten these screws alternately with a
hex-drive bit and ratchet wrench to a final torque of 20 ft-lb for mild steel models and 12 ft-lb for stainless
steel models.
4. Adjust the load cell/channel assembly so it is parallel with the other channel. Measure across the holes in
the front and rear of the channels. Adjust the new cell so that distance is equal, then tighten the load cell
cap screws from underneath to a final torque of 20 ft-lb for mild steel models and 12 ft-lb for stainless steel
models. Check again to be certain the cable will not be pinched by the flexing channel in operation.
5. Finally, put a drop of Loctite on the overload stop screw and set it for a 0.020" gap with the load cell.
Wiring Load Cells into J-Box
Feed the load cell cable into the j-box cord grip closest to its terminal. When facing the scale, the left load cell is
wired to terminal 4 of the j-box, and the right load cell is wired to terminal 1.
Note that the wire traces for cells 2 and 3 (JU-2, JU-3 ) have been cut, making those unused channels inactive.
Connect wires according to Table 2-1 on page 4. Pull excess cable out of the J-box and tighten the cable cord grip
snugly. The rubber seal will protrude slightly from the cord grip when tightened enough to be waterproof.