Service manual

97
How it Works
The MONOPLEX Sofa Control utilizes relay switching to control the power to the two
sofa motors. To limit the amount of current of current drawn, only one motor is allowed
to operate at any given time. When the unit is at rest, all the motor leads are connected
to ground. To operate a sofa motor, 12 volts are applied to the desired motor by the
controller.
To prevent damaging the motors or opening of the fuse or circuit breaker, the controller
senses the current drawn by the motors. If it exceeds a preset level, the controller shuts
off. To restart the motor, release the switch and press it again. This will reverse the di-
rection.
The controller operates by sensing the voltage on the MONOPLEX bus wire. When the
MONOPLEX bus is at 12 volts, the motors are at rest. When the bus is at 6 volts, the
controller drives the recline motor. When the bus is at 0 volts, the controller drives the
slide motor. (Note: This voltage must be read with a voltmeter. A test light will offer too
much load for this circuit). If more than one switch at a time is pressed, the sofa will op-
erate in the Slide mode.
Setting the Stop Adjustment
The STOP ADJUST is used to set the level of current, above which the motor will be
shut off. The proper adjustment of this control is at a level that is sufficient for proper
operation of the sofa, but so high as to overload the fuse or circuit breaker.
Start the setting procedure with the control set in the approximate center of rotation.
Operate the sofa, both slide and recline (lifting the back from it’s open position usually
requires the maximum current.), through the full range. If the sofa stops prematurely,
slightly increase (turn the control clockwise) the setting and test again. If it is hitting the
stops too hard, decrease (turn the control counter clockwise) the setting.
Trouble Shooting
The controller contains three relays to drive the two motors in both directions. A simple
test to see if the controller is operating can be done by disconnecting the sofa motors,
pressing a switch, and listening to the relays. At each press of the switch, at least one
relay should click.
Problem Possible Cause/Solution
Sofa doesn’t
move in one or ei-
ther direction
Sofa jammed. Check for mechanical obstructions. Clear path.
Power not coming from fuse block. Check for 12 volts on pin J1. Replace fuse
Ground connection missing.
Faulty switch wiring. Momentarily ground J7, relays should close, sofa should
slide. If not, check for power at J2, J3, J4, and J5. One terminal has 12 volts.
If not, replace control
Motor wires disconnected or broken. Check and repair wiring.
Sofa doesn’t
move to mechani-
cal stop.
Stop current miss-adjusted. re-adjust Stop control to higher level. (Warning:
raising this setting too high may cause opening of the circuit protec-
tion).