Grasshopper 718D, Service Manual

Page: 9 / 48

9
Control Relay - Model 720, 718D, 721,
721D, and 725
Assuming a normal diode on the circuit,
board, relay B is affected by a problem in
the circuit containing the PTO switch, and
left and right steering switches.
Assuming a normal diode on the circuit
board, relay A is affected by a problem in
the circuit containing the PTO switch, and
left and right steering switches. It is also
affected by a problem in the circuit contain-
ing the parking brake switch and seat
switch.
Circuit Board Diode Problems - Model
720, 718D, 721, 721D, and 725
Refer to the illustration below to locate the
diode on the circuit board between pad R
and A.
Open Diode
An open diode will result in the following
symptoms:
Assuming steering levers out and PTO
switch off, engine can be cranked and
started only with driver on the seat and
the parking brake in the 'OFF' position.
If driver gets off of the seat or puts park-
ing brake to the 'ON' position, the engine
will die.
Shorted Diode
Assuming an operator on the seat and
parking brake is 'OFF', engine can be
cranked and started with PTO switch in
the 'ON' position or steering levers in.
Figure 2
A
R