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Troubleshooting Guide
FOWLER AND KNEE LIFT
The heights of the Fowler and Knee are adjusted by separate motors located directly under the Fowler and
the Knee. The motors are coupled to a worm gear that moves the Fowler or Knee up or down. When the
Fowler or Knee button on either the foot board or siderail is pressed, the signal passes through the CPU and
into the power board, activating a relay on the power board, and energizing the Fowler or Knee motor from
the power board. The motor limits are held using a cam and micro switches. As the Fowler or Knee moves,
the cam is pulled or pushed until a micro switch on both the high and low end of travel is activated.
A.) If the motor electrically stops prematurely or continues to run after its limit is reached, an adjustment of
the cam is probably required (see page 71 or 77). If the switch still does not shut off the motor after the adjust-
ment is made, either the switch is defective, the cabling from the switch is defective or not connected properly,
or the switch is not being recognized by the power board. Check all of these factors to isolate the problem.
B.) If one of the motors is not running at all, listen for a relay “click” on the power board when the appropriate
button is pressed. If the relay is activating, either the power board is not providing proper voltage to the motor,
the cable is not transferring power to the motor, the motor capacitor has failed, or the motor has failed. Check
all of these factors to isolate the problem.
If a relay is not being activated when the button is pressed, check the secondary voltage signals from the CPU
at the power board. If the proper voltage is present at the power board, replace the power board (see page
90). If the proper voltage is not present at the power board, replace the CPU board (see page 90).
SCALE/BED EXIT SYSTEM
Power and logic for the scale and bed exit system comes from the CPU. The most common service requests
on the scale system will be identified as “user issues” so, the first step in troubleshooting a scale problem is
understanding how the system is used (see pages 25–28 for scale system usage instructions). Rule out user
issues by “zeroing” the bed and testing the scale system with a known weight. Verify the change equipment
function is working. If the system checks O.K., it can be assumed the system was not being used properly.
If the system does not weigh within tolerance, re–calibrate the weigh system (see page 87). If, after calibra-
tion, the system still does not weigh accurately, look for a possible defective load cell (see page 87). If a defec-
tive load cell is detected, replace the load cell (see page 88 & 89). If none of the load cells is defective, replace
the CPU board (see page 90).
DMS – DYNAMIC MATTRESS SYSTEM
The integrated DMS mattress system is plugged into the bed and gets its power from the DMS power supply
board and its signalling through the serial IFC board. The DMS power supply board gets its power from the
bed’s power board. All of the logic for the mattress is contained in the control box within the mattress. When
the mattress is plugged into the bed, the DMS LED will illuminate on the outside of each siderail. Rule out
user issues by verifying the mattress is being used properly (see page 21 for DMS usage instructions).
A.) The controls for the DMS are integrated in each siderail. If a problem exists with the controls, isolate the
problem to the siderails (see page 31).
B.) If the DMS indicator LED for manual or automatic does not illuminate and the mattress pump does not
work when the mattress is plugged into the bed, verify the mattress is receiving power by checking incoming
and outgoing voltage at the DMS power supply board. If voltage is present, check the voltage at the serial
IFC board. If voltage is present, the controller unit in the mattress will probably need replacing. If voltage
is not present going into the DMS power supply board, either the cable connections at the board, the cabling
coming from the bed’s power board, or the bed power cord itself are defective. Check all these factors to
isolate the problem. If voltage is present going into the DMS power supply board but not coming out, replace
the DMS power supply board.
C.) If the Air Loss LED comes on, unzip the mattress cover and check for holes in the bladder or air lines or
for loose air lines. If everything is intact, possibly the DMS control unit in the mattress needs to be replaced.
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