Stage Fright

Paul F. Grayson

Here is a frontline story about the panic high-tech mowers cause. This is relevant because turf equipment is adopting the X-By-Wire design approach, and some of it is old enough to need serious troubleshooting and repairs.

Shortly after the season started this year, the electronic brains in the Crown Golf Club’s Jacobsen Eclipses 322 started developing mental problems. There did not seem to be any pattern to when it would work and when it would not, and eventually over the course of a week it quit working completely. The steering was goofy yet manageable, but the fact that the cutting heads would come up after traveling 15 feet made mowing impossible. While trying to cut with individual heads, they eventually all quit working.

This mower is the highest-tech piece of machinery in the Crown’s collection. It has eight computers talking to each other over a CAN bus. This vehicle has its own internal network. (Do I need to add an IT person on my team?) Even the horn button no longer directly controls the horn, instead the drivers action of pressing the horn button sends a signal to one of the computers that looks at the software to see what it should do at this point, then beeps the horn. I began wondering if I had the skills to deal with this or if it was time to consult with a robotpsychiatrist, such as Dr. Susan Calvin, about the machine apparently having a mental breakdown.^*
 

Getting serious

I began my work with a review of the manuals available for the machine I would be working on. Jacobsen provides technical manuals as PDF files online (bit.ly/1RoydTL) and provides technical support over the phone with both regional and factory technicians. The modern maintenance shop needs a computer with high-speed Internet access, a printer and a telephone with long-distance service. The alternative is to print out the 900 pages then bring them to the shop and to use your own cellphone calling plan; whatever it takes to get the job done.
 

Trouble shooting

No matter how complex the system, start by checking the fuses and then looking for anything deranged. Physical damage is always a possibility. In this case, the insulation on the center reel 3-pin power connector had a crack in it (poor strain relief) and was bleeding green copper corrosion.

The 8-pin communication plugs on two of the reel motors, when wiggled, showed intermittent connection (break). A reel motor that says it is turning 0 rpm when it should be turning 1050 rpm is an error that shuts down the mowing units and raises them. The fix was to replace three connector pig tails at about $216 each.
 

Living with X-By-Wire

The introduction of the CAN bus to turf machinery design has allowed machines to behave in useful complex ways such as one-touch mowing. It has also introduced a new complexity to troubleshooting and repair.

Jacobsen is in the process of equipping each of the regional repair centers with a service tool kit that includes known working mower computer modules so they can be swapped out when troubleshooting. This is especially useful when a golf course does not have multiple copies of a mower to swap modules between when troubleshooting.
 

^* Dr. Susan Calvin is a fictional character from Isaac Asimov’s Robot series. She was the Chief Robopsychologist at US Robots and Mechanical Men Inc., the major manufacturer of robots in the 21st century. She was the main character in many of Asimov’s short stories concerning robots, which were later collected in the books I, Robot and The Complete Robot.

Paul F. Grayson is the Equipment Manager for the Crown Golf Club in Traverse City, Mich., a position he’s held for the past decade. Previously, he spent 8½ years as the equipment manager at Grand Traverse Resort & Spa. Prior to that, he worked as a licensed ships engine officer sailing the Great Lakes and the oceans of the world.