Tennant 7100, Service Manual

Page: 292 / 305

ELECTRICAL
4-124
7100 330695 (8 − 11)
IF ERROR READS = ”ZERO BRUSH MOTOR CURRENT”
(SCRUB BUTTON HELD, DOWN PRESSURE LED #1 LIT)
− WHEN THE BRUSHES MOMENTARILY TURNED ON DURING THE
SELF TEST, THE BRUSH MOTOR SHUNT SIGNAL DID NOT GET TO
THE CONTROL BOARD.
− CHECK THE SHUNT & ITS CONNECTIONS AND THE CONNECTIONS
FOR WIRES 88/BLK, 87/CLR & 13AG/SHLD @ CONTROL BOARD
SCRUB SYSTEM
IF ERROR READS = ”LOW BRUSH MOTOR CURRENT”
(SCRUB BUTTON HELD, DOWN PRESSURE LED #2 LIT)
− GO TO MANUAL MODE, TURN ON SCRUB BRUSHES −− VERIFY THAT
BOTH BRUSHES ARE TURNING
− IF ONLY ONE MOTOR IS OPERATING: REPAIR/REPLACE THE OPEN
WIRE OR MOTOR THAT IS CAUSING THE PROBLEM
− IF BOTH BRUSHES ARE TURNING −− IGNORE THIS ERROR −− SYSTEM
TESTS GOOD
− NOTE: CHECK FOR BROKEN BELTS ON CYLINDRICAL HEAD
IF ERROR READS = ”HIGH BRUSH MOTOR CURRENT”
− GO TO MANUAL MODE, TURN ON SCRUB BRUSHES
− MEASURE BRUSH CURRENT WITH AMP PROBE
− REPLACE MOTOR(S) WITH EXCESSIVE AMP DRAW
SELF TEST ERROR
BREAKDOWN
IF ERROR READS = ”BRUSH CONTACTOR OUTPUT”
(BOTH SQUEEGEE AND BRUSH BUTTONS HELD, DOWN PRESSURE LED #3 LIT)
− DISCONNECT 25/GRN AT M1 AND RERUN SELF TEST
− NO ERROR NOW = REPLACE M1
− SAME ERROR STILL: DISCONNECT CONTROL BOARD, IF 25/GRN IS
NOT SHORTED TO GND, REPLACE CONTROL BOARD
IF ERROR READS = ”NO H − BRIDGE ZERO CURRENT”
(SQUEEGEE BUTTON HELD, DOWN PRESSURE LED #3 LIT)
− REPLACE CONTROL BOARD
IF ERROR READS = ”EARLY BRUSH STALL”
(SQUEEGEE BUTTON HELD, DOWN PRESSURE BLINKING LED #1 LIT)
− DISCONNECT BRUSH HEAD ACTUATOR AND RE − RUN SELF TEST
− SAME ERROR: 29/WHT & 30/TAN ARE SHORTED OR CONTROL
BOARD IS BAD
− NOW GET ”NO BRUSH STALL” ERROR: REPLACE BRUSH HEAD
ACTUATOR
IF ERROR READS = ”NO BRUSH STALL”
(SQUEEGEE BUTTON HELD, DOWN PRESSURE BLINKING LED #2 LIT)
− 30/TAN, 29/WHT OR THE BRUSH HEAD ACTUATOR IS OPEN
IF ERROR READS = ”NO BRUSH MOTOR ZERO CURRENT”
(SCRUB BUTTON HELD, DOWN PRESSURE LED #3 LIT)
− IF THE BRUSHEDS ARE ALWAYS ON WHEN THE KEY SWITCH IS ON:
REPLACE M1 CONTACTOR
− IF THE BRUSHES TURN ON AND OFF DURING SELF TEST: REPLACE
THE CONTROL BOARD
− IF NONE OF THESE ERRORS ARE FOUND: THE SCRUB SYSTEM IS
PASSING SELFTEST DIAGNOSTICS
− DETERMINE WHAT OTHER ERROR IS CAUSING THE SELFTEST
FAILURE AND TROUBLESHOOT THAT SECTION