Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/268240
March 2014 | EquipmentWorld.com 36 Wrong or right? "The single most important thing the technician or supervisor should ask is not what is wrong, but what is right," Sullivan says. "There are thousands of answers to the question of what is possibly wrong. There is only one answer to the question of what is working right. You want to choose the question that's going to allow you to winnow down to the simple failure by identifying fi rst those things that are working. Focusing on the 99.9 percent of what is right will inevitably lead to the 0.1 percent that has failed," he says. With mechanical problems, the clues are immediate: noises, shavings in the oil pan, smoke, fi re, rough idle, etc.; so the answer to the "what's wrong" question is obvious. With electronics, something just stops work- ing – mysteriously, so the question "what's wrong" is unanswerable. The only way to begin the diagnosis is to do what Sullivan calls your homework. That means reading the schematics, and, he emphasizes, spending a lot more time reading quietly by yourself than you think you need. Four hour diagnostic "People freak out if you say a four-hour diagnostic is normal," Sullivan says. But if a guy gets four hours to change eight tires, I ought to get at least four hours to fi gure out how to make that same truck run that has six computers in it." Again, electrical diagnoses and repairs are the inverse of mechanical. A mechanic may diagnose in a few minutes what's wrong with a mechanical system. But the repair could take hours or even days. The electrical problem will likely require hours of diagnosis, but then only minutes to repair – often just a corroded connec- tor or frayed wire. It is imperative that both the technician and the shop supervisor understand this, Sullivan says. "The supervisor sets the tone. If the expectation is that this is the proper way to do it, it takes the pres- sure off the technician," Sullivan says. "Otherwise, the technician will go to the machine and start tearing out all kinds of things. They get what I call 'happy hands.' Guys don't know what's going on electrically, so they start tearing things to pieces. It makes the problem worse. The 'I can get it running' mindset is more preva- lent than the 'I can get it fi xed.'" Lack of standards One of the reasons technicians don't like studying sche- matics is that they haven't been taught properly how to understand them, and so they avoid them with reason. There are more than fi ve standards (ISO, ANSI, DIN, etc.) for writing schematics and engineers often mix and match these standards to suit their own purposes. As an example, Sullivan says Caterpillar schematics are drawn as a graphic representation of the location of the parts. The layout of the drawing is the layout of the ma- chine. Deere, on the other hand uses a more European approach in which the schematic is more direct and then you use a different wiring diagram that tells you where the wires and components are. Manufacturers might follow the standards, but not rigorously, Sullivan says. "You can usually assume that their drawings will be 80 percent to the standard and 20 percent their own stuff." The end result is resigned ignorance. "Guys don't know how to read them and they don't want to look stupid, so maintenance | continued Your sweat doesn't earn your bonus. Your expertise does. Smart works. Enroll in Road Institute ® : volvoce.com/Asphalt/ew Reading schematics thoroughly is the fi rst step.