Troubleshooters.Com Presents

Troubleshooting Professional Magazine

Volume 9 Issue 4, Fall, 2005
Copyright (C) 2005 by Steve Litt. All rights reserved. Materials from guest authors copyrighted by them and licensed for perpetual use to Troubleshooting Professional Magazine. All rights reserved to the copyright holder, except for items specifically marked otherwise (certain free software source code, GNU/GPL, etc.). All material herein provided "As-Is". User assumes all risk and responsibility for any outcome.

Steve Litt is the author of the Universal Troubleshooting Process Courseware,
which can be presented either by Steve or by your own trainers.

He is also the author of Troubleshooting Techniques of the Successful Technologist,
Rapid Learning: Secret Weapon of the Successful Technologist, and Samba Unleashed.

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“Don't sweat the small stuff.” -- Proverb


Editor's Desk

By Steve Litt
"When you narrow the problem down to three or four transisters, shotgun em!".

Those words were spoken by my electronics trainer at Pacific Stereo. Knowing absolutely nothing about the process of troubleshooting, I simply took him at his word and did exactly what he said. That was one of the things that, over time, made me one of the fastest techs in the Pacific Stereo's Chicago region.

If you haven't heard the term before, shotgunning is the act of replacing multiple components, even though only one is the root cause. The purpose of shotgunning is economic.

My instructor went on to explain the rationale behind his statement. Each transistor cost roughly a dollar. The labor charge was typically $39.00. Is the customer really going to care whether the total repair charge is $40.00 or $43.00? Probably not. Will the customer care whether I get the receiver back to him today or in  4 days. Definitely. If every repair takes extra time, it can lead to repair cycle avalanche, which occurs when the logistics of reassuring customers of overdue units and maintenance of the masses of to-be-completed units encroaches on actual troubleshooting time, which in turn leads to slower throughput, which leads to more logistics and maintenance, ...

This issue of Troubleshooting Professional Magazine is devoted to shotgunning -- how to do it, when to do it, and perhaps most importantly, when not to do it. As always, if you're a Troubleshooter, this is your magazine. Enjoy.

Steve Litt is the author of "Troubleshooting Techniques of the Successful Technologist".  Steve can be reached at Steve Litt's email address.


This document discusses the practice of replacing functional parts. I do that in my own repairs, and in the past I've done it in repair shop environments. I was taught to do that at Pacific Stereo, within the parameters of appropriateness. Doing so has raised my productivity without significantly raising the customer's repair bill.

When repairing equipment belonging to others, and billing for those repairs, it is possible, and perhaps likely in certain circumstances, that replacing functional parts could get you in legal trouble or saddle you with negative publicity from the media. You, or your organization, needs to decide on your own policies, weighing increased productivity against legal and publicity risks.


You use this document at your own risk. I am not responsible for any damage or injury caused by your use of this document, or caused by errors and/or omissions in this document. If that's not acceptable to you, you may not use this document. By using this document you are accepting this disclaimer.

Why Shotgun

By Steve Litt
"Thirty nine dollars just to look at it???"

If you've ever worked in a retail repair shop, you've come to hate those words. Customers think part replacement is the hard part of a repair, and diagnosis is trivial.

Of course, you know that the opposite is true. Parts replacement takes less than an hour in most cases, but diagnosis can go on and on. That's why you shotgun. If you can replace five cheap parts and save 20 minutes on the repair, then somebody is saving money. If you charge by the hour, the customer is saving money. If you charge flat rate, then you save the money, but you save quite a bit more than the customer spends on the possibly good parts. In such a case, an argument could be made that the customer is actually saving money because shotgunning enables you to set your flat charge lower on all customers.
Steve Litt is the creator of the Universal Troubleshooting Process.  Steve can be reached at Steve Litt's email address.

Shotgunning and Intermittents

By Steve Litt
Doesn't it seem like the better you get at troubleshooting, the more intermittents you see? Six months ago an event occurred in which my computer simply turned itself off. It never happened again.

Til last night. After I replaced a defective DVD+RW drive, click, it went off. I noticed that the computer was plugged into a power strip that was in turn plugged into the UPS. The power strip was cheap, old, and the switch didn't seem to work too well. I went back to work, wondering if the power strip was the root cause.

Click, it went off 20 minutes later. I got really mad.

I'd had a tough day. I was putting the finishing touches on a backup program that is configurable from an outline. The bad DVD+R player had made it look like my backup program didn't work, requiring hours of needless debugging. Finally I exchanged the bad DVD+R, and it looked like my backup program was working except for some minor details. But it was 11 pm, and I was tired, and in no mood for any more problems.

If there's one thing I know, it's that you never troubleshoot when you're mad. I knocked off, figuring tomorrow is another day. While I was showering it occurred to me that it might be nice to perform a couple general maintenance items and then leave the computer cooking overnight.

So I replaced the AC cord, and I lubricated the contacts where the power supply connects to the motherboard. It's been 12 hours, and so far, no clickoff. The next step will be to put the cover back on the computer -- both events last night were with the case on.

Computer AC cords cost about $5.00 apiece, so I want to keep that AC cord. But if the event doesn't recur within a couple days, I'm cutting up that cord and throwing it away, even though it's more likely that the problem was caused by corroded contacts between the power supply and the motherboard.

Why would I do that?

The slowest reproducible problems to fix are the ones where a wrong assumption isn't tested. Most such situations are avoidable, and shame on the Troubleshooter if she doesn't test assumptions. But some assumptions must remain untested for productivity. Chief among such assumptions is the assumption that the "known good" part is really good. If I put a suspicious cord back into my stash of cords, a couple months down the road it could complicate a troubleshoot.

But wait, there's more. This cord isn't suspected only of being defective, it's suspected of being intermittently defective. Its use in a swap could cause a problem not detectable in testing -- a problem that could crop up days or months after its insertion. It could cost days of troubleshooting. $5.00 is a cheap price to eliminate that possiblility.

In fact, I routlinely destroy and dispose of suspected intermittent components. Chief among such components are computer IDE cables. If I swap it out I'll probably trash it, unless it's quickly obvious that the symptom occurs also with the new component. When a motherboard is suspect in an intermittent, I'll trash it unless I can prove it's not the cause. Yes, I'm throwing away $79.00, but I'm guaranteeing that it won't cause an intermittent in the middle of a troubleshooting course.

When one or more components are implicated in an intermittent, unless they can quickly be proven non-causes, the dumpster is your friend.

Steve Litt is the creator of the Universal Troubleshooting Process.  Steve can be reached at Steve Litt's email address.

Shotgunning and Maintenance

By Steve Litt
You're fixing a six year old, heavily used server computer with an intermittent disk problem. Both its IDE cables and its floppy cables are dusty and old. So you shotgun both IDE and the floppy cable.

Why did you do that?

Because in any reasonable preventive maintenance program, those cables would have been replaced already. If there's not something wrong with them now, there very well might soon be. Meanwhile, replacing them might fix the problem. So you swap them, lubricate their electronic contacts, and cook the computer to see if that fixed the problem. If not, continue.

If you were doing this work for a customer, and if swapping the cables didn't fix the problem, ethically you'd need to get the customer's consent.  Just let him know you can't warranty your work unless he lets you replace the cables. That should do it.

Shotgunning is an excellent idea when dealing with old components that should have been replaced under a preventive maintenance program.

HOWEVER, if you're in a repair shop environment, you must be aware that even replacement of old but still functioning components could get you a consumer affairs investigation or an undercover visit from the local TV channel. In a repair shop environment where you repair other people's gear, the best strategy is to tell the people exactly why you want to replace the old but still functioning parts, possibly denying them warranty if they do not, and then give them the choice.
Steve Litt is the creator of the Universal Troubleshooting Process.  Steve can be reached at Steve Litt's email address.

Appropriate Shotgunning

By Steve Litt
There's a fine line between replacing good parts to make repair more efficient, as opposed to replacing good parts because of incompetence or greed. If you fall on the wrong side of that line, you just might end up with some very bad media coverage, or even legal problems. Not a year goes by when the media doesn't expose a repair facility for "unneeded repairs", including some very large outfits that are household names.

To be appropriate, the shotgunned parts should be cheap relative to the entire repair. In the case of Pacific Stereo, the added cost was usually less than 10%.

Second, at least one of the shotgunned parts should cure the problem. Otherwise you're not shotgunning, you're practicing diagnosis by serial replacement. Diagnosis by serial replacement at least causes customers to hate you, and might get you on TV in a way you don't like.

Of course, the worst practice is performing unnecessary repairs to pad the repair bill. That's illegal and unconscionable. Anyone doing that should be put out of business.
Steve Litt is the author of the Universal Troubleshooting Process courseware.   Steve can be reached at Steve Litt's email address.

Is Appropriate Shotgunning Fair to the Customer?

In other words, is it ethical?

I think appropriate shotgunning is fair to the customer, and is ethical. Here's why:

For one thing, if you charge by the hour of actual work, shotgunning can lower the customer's bill. Reduced cost for an equivalent (or better) repair seems obviously fair and ethical, at least to me.

If you charge a flat labor charge, and the added cost is not significant, I still think it's fair. If it weren't for shotgunning, you'd need to raise that flat labor charge. Maybe not as much as the cost of the shotgunned parts, but you'd need to raise it for all customers, even those needing no parts replacement. Given the cost of the shotgunned parts is a small portion of the total bill, I think this is fair and ethical.

As the cost of the shotgunned parts rises, fairness and ethics come more into question. If you're unsure, perhaps the best policy is to bring the customer into the loop. Perhaps you can explain that you warranty only the parts replaced, and if other parts turn out problematic, they'll need a costly new repair. If the parts are old, describe the preventive maintenance advantages. Then let the customer make the decision.
Steve Litt is the author of Troubleshooting Techniques of the Successful Technologist.  Steve can be reached at Steve Litt's email address.

Is Appropriate Shotgunning Legal?

By Steve Litt
I am not a lawyer. I do not know whether it's legal. That's something you need to find out.

I imagine it varies from state to state. If you fix other people's equipment, you should check this out with a lawyer or someone very knowledgeable. If you fix your own equipment or the equipment of your employer, legality is a moot point.

Please keep in mind that state attorneys general and investigative TV reporters don't understand repair, and don't cut repair shops much slack. Like most of the populace, they think that the bulk of the repair is actual parts replacement, not determining which parts to replace. They look with skepticism on honest mistakes.

These are issues you need to consider before shotgunning when repairing equipment belonging to others.
Steve Litt is the author of Troubleshooting Techniques of the Successful Technologist.  Steve can be reached at Steve Litt's email address.

Should I Shotgun?

By Steve Litt
There's no easy answer, so I won't answer that question. In this magazine, I've tried to lay out information so you can make your own choice.

I shotgun. I shotgun on repairs I do for myself, and for customer owned equipment when I was in the stereo repair business. I shotgunned both in my own shop, and in shops owned by others. I always made sure such shotgunning didn't inflict much additional cost on the customer. If in doubt, I brought the customer into the decision making process. I was never adversely publicized on TV, nor was I investigated by the Better Business Bureau nor Consumer Affairs. I never felt guilty. Your mileage may vary.

It's your choice to make. The one piece of advice I can give you is if you decide to shotgun, be sure you're doing it to increase productivity. Be sure you never do it to pad a repair bill or cover up for diagnostic ineptitude. Be sure that any added cost to the customer is minor when compared to the entire bill.

From an ethical viewpoint, ask yourself what you'd do if the equipment belonged to your mother, and she was paying you.
Steve Litt is the author of Troubleshooting Techniques of the Successful Technologist.  Steve can be reached at Steve Litt's email address.

Letters to the Editor

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