Kipp&Zonen Brewer MkIII - Manual (Page 31)

MKIII SERVICE MANUAL 26
7.3 TRACKER ELECTRICAL PROBLEMS
Electrical problems include AC power, power supply, motor driver board, stepper motor, and
sensor/blocker assembly.
7.3.1 Sensor Problems
The tracker is prevented from travelling past the zero (or North) position by a sensor that is
attached to the aluminum drive plate. A blocking device which rotates with the Tracker body cuts a
light beam in the sensor and the resulting change in sensor voltage output is detected by the
electronics.
If it is observed that there is frequent wrapping of the power and communications cable, or
activation of the safety switch, the sensor and its wiring should be tested.
1
With a DC voltmeter, monitor the sensor voltage at U3, pin 13 on the Main Electronics Board.
2
Pass a piece of paper (or other opaque material) through the sensor, and the voltage should
go from +5 volts in the blocked state to 0 volts in the non-blocked state.
3
At the Tracker, pin 5 of J201 should go between 0V and 5V as the sensor is unblocked and
then blocked.
4
Replace the sensor assembly and cables as necessary.
5
If the above tests shows the sensor and cables are good, then confirm that the blocker passes
through the sensor as the Tracked rotates.
6
If all of the tests are good, there could be a problem on the Main Electronics Board sensor
detecting circuitry, in which case KIPP & ZONEN should be consulted.
7.3.2 No Tracker Operation.
If the Green Power Indicator indicates no Tracker power, but the Brewer functions normally, a
problem in the Tracker is indicated.
The Tracker covers should be removed and the AC power to the Power Supply confirmed. If AC is
present then the +5 V output of the power supply should be measured. If no +5V is found, then the
Power supply is at fault and should be replaced.
If the Power supply is normal, then the safety switch should be inspected to confirm that it has not
been tripped by an over travel condition. The switch should be in the toggle position away from the
Tracker centre pedestal.
If the Power Supply and safety switch are both normal, and there is still no motor motion, then it
should be confirmed that the Brewer is outputting drive pulses to the Tracker.
1 Tracker movement pulses can be found on the cable going to the Tracker Driver Board BA-
C99, connector P201, pin 1. Square pulses, 0-5V in amplitude may be observed with an
oscilloscope, or an AC reading indication of 2 Volts can be seen with an AC Voltmeter.
2
Connect an Oscilloscope or Voltmeter to pin 1 of Connector P201 of the Board BA-C99 in the
Tracker. (lower left of the BA-C99)
3
From the Brewer Main Menu, go to the TeleType mode.
4
Send the Command M,2,1000 and pulses should be observed.