Fourteen Secrets of Problem Solving

Here are 14 secrets of problem-solving, learned from years of experience at the computer hardware repair bench. Perhaps they will also be found useful in medicine and other fields!

Note: You can also get here by typing into your browser: test-bench.info. (Don't forget the hyphen).

1. Two problems?: Solve the easy one first.

Two problems at the same time can be very confusing, especially if we think there's only one problem. The indications will be scrambled. Anything we try won't seem to work. The solution is to recognize that there are two malfunctions; not one.

Eliminate the easy one first. Get it "off the table"! Now the second problem may still be difficult; but much less so.

Bridge guru Eli Culbertson would say "Get the little kiddies off the street."

2. Be suspicious of the solitary "good guy".

one bad Sometimes a computer's single memory location will be working correctly, and all the others will be returning wrong data. This is probably what is known as the "double-select" problem. The one that looks good is the one that's causing all the trouble: he's always selected.

3. Learn footprints.

Some problems seem to occur rather often. They likely have footprints; characteristics that we can recognize.

4. Progressive redefinition of the problem.

Homing in on the solution to a problem is a process of progressive redefinition. For example: 1: "This machine doesn't work." 2: "Windows isn't coming up." 3: "The disk activity light isn't coming on." 4: "Bad disk." Problem solved! Each step creates a narrower definition.

5. Don't ask what is wrong; ask when it is wrong.

ask when From #5 above, we can see the value of thinking in terms of "when, in the sequence, is it failing?" This secret is already known by doctors ("When did you first notice the pain?"), and detectives ("Did the scream come before the shots?").

6. "If it ain't broke don't fix it."

This is self-explanatory. But a word of caution: If we overdo the "hands-off" approach, then when there really is a problem, we may feel lost because the equipment will have become unfamiliar.

7. Know how it's supposed to work when it's not broken.

It has been said that all troubleshooting is based on comparison. If we compare what is supposed to happen with what is happening, we will know when the problem manifests itself, and we will be able to home-in.

8. Push the problem around.

Sometimes a problem will seem to be "going into hiding"; for example, an intermittent problem. Try to cause the problem to repeat itself more often; perhaps by applying heat, cold, looping software, etc.

9. Intermittent problem: Does anything look wrong?

One minute the machine is working fine; the next it's sick. Intermittent problems are especially difficult to troubleshoot. We check the signal at one point, and it decides to measure OK; but that's a throw-off! Or we exchange a component - seems to fix it. It's working! Then: "Oops! it's still broken."

In cases like this we can often get lucky if we perform a careful visual inspection. Look for discolorations, foreign objects, etc. Anything that looks even slightly wrong is worth investigating further.

Note: Another solution for intermittent problems is #9 (Push the problem around.)

10. Cut the problem in half.

There are only a finite number of components that can be bad. If we could cut that number in half enough times, we would get it down to a single one.

11. Remove candidate bad stuff one at a time.

Is the disk light bad? Check it. OK? Good! Next: Is the disk running? Yes? Good! Next: (Keep doing that.) See #13.

12. Get something working.

When we're stuck and feeling down, it is good for our own morale to know we're making some kind of progress. Grow a list of more and more things that we know are working correctly. Start with the voltages and the clocks. Then put in a start-up PROM with every instruction a no-op.

13. Fight!

Sometimes it seems as if we'll never find the solution. Our confidence is faltering; that makes the situation even worse. If we fight back, it has a positive psychological value on ourselves, if nothing else.

There's an old Quaker parable about a frog that got caught in a pail of cream. He tried to jump out, but the cream was too thick. He didn't have any other ideas, so he just kept on kicking anyway. He churned the cream into butter, hopped off the top, and was on his way!

14. Take a break.

Something happens when we take a break. There may be a wrong idea stuck on our mind, a blind spot, or whatever. On returning from the break we will frequently see the solution immediately.