Warner Electric • 800-825-9050
P-0257-WE • 819-9027
23
TROUBLESHOOTING
Applies to MCS-204 Control,
MCS-166 Power Supply
With the exception of the dancer input, general MCS-166/MCS-204 system troubleshooting is quite similar to
troubleshooting the MCS-166/MCS-203. The chart below will be helpful in isolating problems causes.
Probable Cause
Suggested Solution
No DC power to the control.
Check for power LED illumination on MCS-204.
Check for power LED illumination on MCS-166.
Check fuses.
Check proper DC input connections to control (refer to tension control hookup
instructions).
Check AC power input to MCS-166, if used.
Brake is not engaging.
Check to be sure lead wires to the brake are at the brake terminals and at terminals
1 and 2 of the control.
Check to see if input is properly connected.
Using a voltmeter, check for approximately -1.8 to +28 VDC between the brake
terminals.
If there is no voltage, check for approximately -1.8 to +28 VDC between terminals
1 and 2 on the control. If the voltage is present at the control and not at the brake,
wires to the brake are open, If there is no voltage at terminals 1 and 2 of the control,
replace the printed circuit board assembly.
If there is voltage at the brake terminal, check the brake coil resistance with an
ohmmeter for shorted brake magnet or wrong magnet voltage.
Check for proper input signal.
Check to see that brake Is wired properly.
Check to see that Brake-Off input is not activated.
Brake does not have the torque capacity
required for the application.
Verify that the correct brake was selected by repeating the selection procedure.
Brake is not releasing as input level decreases
Check the mechanical parts of the brake to assure they are in good operating
condition and properly installed. Check to see if Brake-On input is activated.
Roll shaft not free to rotate with control off.
Inputs incorrectly connected to control
terminals.
If brake LED off?
Brake and shaft must be free to rotate with control off.
Verify input connections.
Using a voltmeter, check the DC voltage at the brake terminals as follows. Slowly
reduce the input level and observe that the voltage decreases - then slowly increase
the input level and observe that the voltage increases.
(Problem occurs near roll core only)
Residual torque of the unwind stand exceeds
the minimum torque allowable for the
application.
With input level at minimum settings, check that the DC voltage at the brake terminals
reduces to 0 and reverses polarity.
If the voltage reduces and reverses polarity, check to be sure that the brake is in good
operating condition and properly installed (see tension brake maintenance-torque loss).
Also check to be sure that the unwind stand friction is not excessive for the application.
Check the brake selection procedure to be sure the brake being used does not exceed
the minimum allowable torques. If the voltage did reduce to zero but did not reverse
polarity, adjustment of the antiresidual may be necessary. If adjustment of the antiresidual
does not cause the brake voltage to reverse polarity in the off state, replace the PC Board
Assembly.
