Troubleshooting Professional

Back IssuesVolume 2, Issue 2, February 1998Back to Troubleshooters.Com
Copyright (C) 1998 by Steve Litt


In 2005, the term General Maintenance was replaced with Corrective Maintenance, which better describes the purpose of the maintenance. These terms are synonomous, so you can use either term, but courseware updated in 2005 and later uses the term Corrective Maintenance.


Editors Desk
Benefits of Appropriate General Maintenance
It's Not Rocket Science
General Maintenance and Intermittents
The Theory of General Maintenance in Reproducible Problems
What is Appropriate General Maintenance?
Letters to the Editor
How to Submit an Article
URLs Mentioned in this Issue

Editors Desk

By Steve Litt
I recently received several letters from a woman whose brand new car had been in the shop, with the same electrical problem, several times in the year and a half she's owned the car. No fix. Cruising the 'net, I saw a site on electrical grounds in cars -- amazing how much havoc a faulty ground can cause.

That brought to mind a conversation with another woman whose car was in several times for the same problem. She commented that these guys simply plugged her car into a computer and replaced whatever the computer program said to replace. She'd spent lots of money, but the problem was still with her. Could a computer program deduce a bad ground, or a loose nut, or corrosion causing a short between two wires? I doubt it.

My 1967 Dodge's brake lights wouldn't go on, so I took it to Perfection Auto Care in Reseda, CA. It took 2 mechanics an hour and a half, plus a replaced brake light switch, a replaced bright light switch, and a replaced bulb, before they found the real problem -- a bad ground in the rear drivers side light housing. A little sandpaper and SHAZAM, it's worked for months. The turning point in the repair was when the parking lights went on without turning them on, and this symptom could be toggled by moving the light housing. But what if those mechanics had been slaves to their "diagnostic computer", or just hadn't had the years of experience they had had? I'd have had half the car replaced without fixing it.

Then there's the saga of my wife's 87 Buick. Four replaced computers in the life of the warrantee, and it still stalled on the freeway. Looked like a typical mid-80's GM lemon, a Roger Smith Special. I suggested she take it to Bill Murphy Buick in Culver City, CA., who had done good work for me before. She handed the car to the Murphy techs with a complete symptom description. The verdict? A cable connected to the computer was intermittent. I'll bet they found it by scoping the computer and wiggling everything -- general maintenance. The computer had always been OK, the cable was feeding it garbage. Garbage in, garbage out. The Roger Smith Special has been a wonderful car ever since.

The point of the previous four paragraphs is this: There are some problems, very hard to solve analytically, which are easy to solve with appropriate general maintenance. That's why Do the Appropriate General Maintenance" is step 5, just before step 6, "Narrow It Down". The effective Troubleshooter knows how to use General Maintenance to best advantage.

General Maintenance allows solutions with a minimum of expended brainpower. It's elegant in its simplicity and can be done many ways. This issue contains several articles on Appropriate General Maintenance.

Each of us has his or her own approach to Appropriate General Maintenance, optimized to our habits and abilities. As you read this issue, see how it applies to you. Where do you agree or disagree? Does it offer info that you find helpful? And remember, if you're a Troubleshooter, this is your magazine. Enjoy!

Steve Litt can be reached at Steve Litt's email address.

Benefits of Appropriate General Maintenance

Boosts Productivity

Doing the Appropriate General Maintenance before the Narrowing Down process boosts productivity two ways. First, the Troubleshooter can catch a lucky break, repairing in minutes something that would otherwise have taken hours. Take a malfunctioning circuit board. A thirty second look can reveal that the factory wave solder was less than optimal, with several suspicious looking solder joints. The Troubleshooter can trace it down to the one bad joint, fix that, hope there's only one bad solder joint, and hope none of the others go bad during the repair warrantee period. On a complex circuit that could take hours. Or the Troubleshooter can take twenty minutes to re-solder every connection on the board, then test to see if the symptom's gone away. I'd certainly choose the latter if productivity (and incidentally, quality) were a concern.

The second way Appropriate General Maintenance boosts productivity is by preemptively striking against the toughest problems. A great example would be checking to make sure a computer's motherboard was screwed down tightly, and grounded properly. Say a grounding screw on the motherboard wasn't making contact because of a misplaced insulating washer. That might create a "current loop", which erroneously triggers certain logic circuitry under certain conditions, which causes a "won't boot" symptom description. A 30 second inspection would reveal the bad ground. Barring that, what are your alternatives?

  1. Spend hours with a VERY high frequency (read that expensive) oscilloscope, slowly tracing the problem to the missing ground. Cost: hours of unpaid work.
  2. Replace the motherboard. If the Troubleshooter puts back the grounding screw the same way, there's wasted time and they still need to do #1 above. If the grounding screw is put back the right way, it will appear like the new motherboard fixed the problem. Cost: The customer pays for the motherboard he doesn't need, most of that extra money going to the motherboard vendor, not to the Troubleshooter or his shop. In the event that the customer brings his old motherboard to another shop who correctly diagnoses the problem, there's a consumer affairs complaint in the wings. Or maybe a 20/20 TV episode.
Often the toughest problems involve things we don't consider "components" -- screws, chassis, electrical connections, wires, etc. Since we disregard them as components (and rightfully so, we have enough to worry about), a defect in such a non-component could send repair time and cost into the stratosphere. Add to this that more and more troubleshooting is done via "diagnostic software", which usually doesn't take into account these "non-components". Such automated troubleshooting, in the face of a simple defect in a wire or a loose screw, often results in a series of replaced parts without a solution. It's just these "non-component" defects against which Appropriate General Maintenance is most effective.

Conserves Brainpower

A mind is a terrible thing to waste. The less you have to think, the more mental muscle you have left over for those really tough repairs. It's obviously a lot easier to clean a cars battery terminals and give it an in-car charging test than to track a "won't start" problem all over the car. If that one minute test produces no results, now's the time to roll up your sleeves and start to diagnose.

Minimizes Burnout

If Appropriate General Maintenance conserves brainpower and enhances productivity, it obviously lessens the chance for burnout. When I was a repair tech on commission, I saw a lot of techs burn out. Some quit, some went to the mental hospital, and some required medication. It was never pretty. Since general maintenance makes life easy, use it.

Minimizes Overrepair/Overcharging

I wish I had a dime every time a bad electrical or mechanical connections resulted in unnecessary parts replacements (Sears Auto Repair division got popped for this -- see the 6/11/1992 Los Angeles Times article by Denise Gellene). Appropriate General Maintenance reduces the risk.

Reduces Need For Specialized Training

As a professional Troubleshooter, I'm usually the LEAST knowledgeable on the scene when it comes to the equipment/system under repair. In spite of that, I've often looked like a hero simply by solving a problem with General Maintenance. Likewise, a Troubleshooting workforce that consistently applies Appropriate General Maintenance the right way can often forgo some specialized training, thereby saving training costs and absent (at training) labor costs.

Less Escalation

How many of those problems "kicked upstairs" to a more technical troubleshooter turn out to be a bad connection, dirty contact, intermittent wire, or other maintenance item. On such problems, a first level support department trained in General Maintenance can reduce escalation, and solve the problem in less time than the phonecall/paperwork necessary to transfer ownership of the problem to the next level.

Manageable with Written Documentation

It's really hard to document the testing process to narrow down a problem. On the other hand, it's trivial to document how to clean battery terminals, check for loose screws, etc.


Good use of Appropriate General Maintenance results in a more productive, smaller, happier workforce, with better customer satisfaction, less complaints, and decreased costs.
Steve Litt is president of American Troublebusters and Troubleshooters.Com, and editor of Troubleshooting Professional Magazine. He's also an application developer and technical writer. He can be reached at Steve Litt's email address.

It's Not Rocket Science

By Steve Litt
The kid was no rocket scientist. The low frequency model of a transistor was a little more than he could handle. Yet here he was, sitting right next to me, training for the same audio tech job as me. The trainer frequently "checked in" with the kid to see if he got it. He usually didn't. Progress was slow. Amazing they had hired him.

Still more amazing, when training was over, he out-performed me. At least for the first 6 months. I had a BSEE, he had, um, he had -- hey, what did he have anyway? Whatever it was, it wasn't rocket science. I heard it through the grapevine. The kid wasn't much with electronics, but he could move heaven and earth with a heat gun, freon, and tuner spray. Six months later, I developed a sure fire way for narrowing down problems (divide and conquer), and left the kid in the dust. A year later I realized I should clean the switches and controls and wiggle circuit boards before starting in on a detailed narrow-down. It wasn't until ten to twelve years later that I understood the full significance of what the kid had been doing.

It's not rocket science. A young kid with little training and maybe average intelligence made a living with it. It took me ten years to fully master. Hey, who's the rocket scientist anyway?

Steve Litt can be reached at Steve Litt's email address.

General Maintenance and Intermittents

By Steve Litt
Troubleshooters.Com repeats over and over again that it's a mathematical certainty you can repair a reproducible problem in a well defined system. There's no such guarantee in an intermittent problem. With intermittents, no test is conclusive. The symptom might have vanished for reasons unrelated to your test.

This leaves the Troubleshooter with three options:

  1. Use statistics rigorously to produce statistically conclusive tests.
  2. Convert the intermittent to a reproducible.
  3. General Maintenance.
#1 will be wonderful when it's implemented. It requires a computer with output devices to toggle various thermal, electrical and mechanical properties, sensors to detect various states of the system, and a program to detect statistically significant trends between the outputs and the inputs. Each type of system to be tested will need its own output devices, sensors, and specific instructions for mounting and connecting them. It will be wonderful, but right now it's science fiction.

#2 is what we all try to achieve, as it's the surest way to a fix. However, it's often impossible, and usually time consuming.

That leaves #3, General Maintenance, which we'll define to include non-rigorous thermal and mechanical toggling (freon and heat gun, grabbing things and wiggling them). General maintenance, including the more expensive forms which wouldn't be appropriate in a reproducible (for instance, re-seating every card and cable in a computer), is often the most economical approach to intermittent problems and should be tried first.

Steve Litt can be reached at Steve Litt's email address.

The Theory of General Maintenance in Reproducible Problems

By Steve Litt
"Do the Appropriate General Maintenance" is Step 5 of the Universal Troubleshooting Process, coming right after Step 4: "Reproduce the Symptom", and before Step 6: "Narrow it Down to the Root Cause". The whole purpose (at least in reproducible problems) of this step is to save time and brainpower. Unlike most other steps in the process, General Maintenance is unnecessary to the solution of the problem (at least on reproducible problems).

The Universal Troubleshooting Process

1. Get the Attitude
2. Get symptom description
3. Make damage control plan
4. Reproduce the symptom
5. Do Appropriate General Maintenance
6. Narrow it down to the root cause
7. Repair or replace the bad component
8. Test
9. Take pride in your solution
10. Prevent future occurrence

Contrast Step 5 with steps 2, 4, 6, and 7. Without the latter steps, a solution usually cannot be reached. Without a symptom description and symptom reproduction, the tech doesn't know what problem to solve. Without narrowing it down, it's impossible to solve the problem unless the problem is a General Maintenance item. And without repairing or replacing the bad component, the system remains in its defective state. Not so with general maintenance.

It's perfectly possible to narrow down a problem to a dirty battery terminal, a bad solder connection, or a lack of transmission fluid. It's just time consuming, and brain intensive. By treating as general maintenance items which are easy to check and likely to cause problems, Troubleshooters have found they can produce more with less time and less thought.

Appropriate General Maintenance works its magic by allowing the Troubleshooter to do the following:

Catch a Lucky Break

Life is an educated gamble. Those who consider the odds do the best. When considering odds, we consider four factors:
  1. Likelihood of success
  2. Cost of successful gamble
  3. Cost of failure
  4. Reward of success
Appropriate General Maintenance is the gamblers choice, with high likelihood of success, and high reward of success (generally time saved), low cost of successful gamble (doesn't take long), and low cost of failure (doesn't ruin anything). By choosing, as Appropriate General Maintenance, those procedures most likely to gain you more time than lose, you'll be likely to turn your "lucky breaks" into extra time, hence profit.

Perhaps the greatest example of a "gamblers choice" Appropriate General Maintenance is now obsolete. Some readers may remember that early radios (before about 1965) used vacuum tubes instead of transistors. Vacuum tubes wore out regularly, as opposed to the other components which were fairly reliable. You could repair 90% of all tube radio problems within 1/2 hour. You'd start by visually inspecting for blown (literally exploded) capacitors, and replacing them. Then you'd test each tube in a tube tester and replace the defective ones. General Maintenance. No though, little time. The other 10% were a real problem due to the non-modular layout and design of tube radios, making use of Appropriate General Maintenance vital.

Preemptively Strike Against the Toughest Problems

Often the toughest problems involve things we don't consider "components" -- screws, chassis, electrical connections, wires, etc. Since we disregard them as components (and rightfully so, we have enough to worry about), a defect in such a non-component could send repair time and cost into the stratosphere. Add to this that more and more troubleshooting is done via "diagnostic software", which usually doesn't take into account these "non-components". Such automated troubleshooting, in the face of a simple defect in a wire or a loose screw, often results in a series of replaced parts without a solution. It's just these "non-component" defects against which Appropriate General Maintenance (switch and connection cleaning, electrical connection reseating, screw tightening, fluid level checking, etc.) is most effective.
Steve Litt can be reached at Steve Litt's email address.

What is Appropriate General Maintenance?

By Steve Litt
In Troubleshooting Theory, we expand the concept of Appropriate General Maintenance to include things that might otherwise not be considered maintenance. Generally, Appropriate General Maintenance falls into these categories:

Normal Preventative Maintenance

The customer comes in with a "car won't start" complaint. According to its markings, the battery is seven years old. After reproducing the symptom, the battery should be replaced as preventative maintenance. Obviously the customer must be informed that the battery may not be the only problem, but it should be replaced. If the customer declines maintenance replacement of the battery, he should be informed that if the problem is TRACED to the battery, the customer will pay for the time that tracing took. And whether or not the problem is traced down to the battery, the repair warrantee will not cover subsequent problems caused by the geriatric battery.

Depending on the repair facility's relationship with the customer, further testing may be done after Preventative Maintenance fixes a problem. For instance, if the tech and the user are employees of the same business and have a good relationship, it's likely they'll agree that the tech will do no long term testing (like checking the car's charging system), but instead to have the user "long term test" the maintenance repair, with the knowledge that the repair hasn't been proven conclusively. On the other hand, if substantial money has changed hands, or if there's not enough trust between tech and user, or if safety is an issue, the tech will need to do complete testing. In the car example, he'd need to test the charging capacity of the old battery, check the voltage output of the car's charging system over time, and test for current draw when the car and all its lights and accessories are "off".


Anything Obvious.

As a really green tech, I repaired a circuit board with a visually burned 2 watt resistor. Rather than investigating the circuit feeding the resistor, I simply continued to troubleshoot the whole board. The repair took a long time.

Think I was foolish? Let the non-foolish cast the first stone. How many times have good techs ignored the exact phrasing of computer error messages ("I think it said "system error""). How many times have they not looked for a file named in a "file not found" error message? How many times have they not investigated the config.sys FILES= statement when a "too many open files" error occurs?

Observe, observe, observe. Treat anything obvious as a gift, and use it.


Anything that should be done before completion.

The factory has issued a modification, and your shop's policy is that this modification be done on every unit coming in for repair. The cost difference between doing this mod before narrowing down, as opposed to after, is zero. So if there's any possible connection between the mod and the symptom, do the mod first.


Any easy maintenance item.

Here's where you're playing the odds. If the likelihood of the maintenance item solving the problem, factored by the reward of solving the problem, is greater than the cost of the maintenance item, factored by the likelihood of the maintenance item NOT solving the problem, do it.


Because this is so subjective, no examples will be given.

With an intermittent, any maintenance which could cause the symptom.

As discussed in General Maintenance and Intermittents, much costlier General Maintenance are appropriate, because intermittents close off the Troubleshooter's access to conclusive tests via Divide and Conquer.

In these cases, make sure the customer knows this is an educated guess, not a guaranteed solution, and that he or she must pay for the service, not the outcome. Make sure he or she agrees to this, and if not, consider declining the repair.


Steve Litt can be reached at Steve Litt's email address.

Letters to the Editor

All letters become the property of the publisher (Steve Litt), and may be edited for clarity or brevity. We especially welcome additions, clarifications, corrections or flames from vendors whose products have been reviewed in this magazine. We reserve the right to not publish letters we deem in bad taste (bad language, obscenity, hate, lewd, violence, etc.).
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How to Submit an Article

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URLs Mentioned in this Issue Steve Litt's website. Documents Sears Auto Centers' 1992 fall from grace -- unnecessary installed parts. Documents Sears Automotive Center Consumer Litigation, Action No. C-92-2227, Honorable Robert H. Schnacke.

Bill Murphy Buick (310) 837-1211.

Perfection Auto Care (818) 343-6789.