Transient Voltage Suppression (Tvs) Diode - Toro Groundmaster Series Service Manual

Transient Voltage Suppression (TVS) Diode

Testing the Transient Voltage Suppression (TVS) Diode
Electrical System: Testing the Electrical Components
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1. TVS diode
A transient voltage suppression (TVS) diode assembly is used to protect the
electrical system components from power surges created by energizing and
de-energizing the PTO clutch coil. The TVS diode plugs into the main wire
harness above the right rear corner of the operator's platform. The TVS diode
can be identified by its yellow color and TVS diode symbol on the end of the
diode body.
If the TVS diode fails, it may cause a short in the circuit. This type of failure would
cause fuse FB1–F4 to blow. Test the TVS diode if fuse FB1–F4 blows repeatedly.
If the TVS diode fails, it may cause an open circuit. This type of failure could
damage the TDM controller output for the PTO clutch. Test the TVS diode if the
PTO clutch coil does not energize or de-energize correctly.
1. Park the machine on a level surface, lower the cutting unit (or attachment),
engage the parking brake, set the key switch to the O
the key from the key switch.
2. Locate and remove the TVS diode from the wire harness. Check the diode
and the diode holder for damage or corrosion and clean or repair if necessary.
3. Use the table provided and a multimeter (ohms setting) to measure the
resistance across the diode terminals.
Multimeter Multimeter
Red (+) Lead Black (-) Lead
DIODE DIODE
TERMINAL A TERMINAL B
DIODE DIODE
TERMINAL B TERMINAL A
4. If testing determines the TVS diode is faulty, replace the diode.
5. If the TVS diode tests correctly and a circuit problem still exists, check the
wire harnesses; refer to
6. After testing is complete, make sure the TVS diode is fully installed into the
connector and secured to the wire harness.
Figure 101
Desired
Resistance
VERY LOW
VERY LOW
Appendix A (page
Page 6–52
position and remove
FF
A–1).
Groundsmaster ® 3200, 3300 and 3310
19240SL Rev A