Page 185 - Troubleshooting Analog Circuits

14. Real Circuits and

Real Problems

“Congratulations! You are the proud owner of a brand-new Varoom Automobile. It
has been built with the highest old-world craftsmanship and the finest computerized
engineering, to assure you of many miles of trouble-free driving. Nothing can go
wronX.
“Just in case of some problems, Varoom Motor Co. is pleased to include the fol-
lowing table for troubleshooting:

Troubleshooting Table

Problem: Car will not run.
Indication of Problem: Solution:
Ash tray is full. Use Ashtray-Empty computer procedure.
Fuel gauge reads Empty. Purchase fuel.
Fuel does not reach engine. Replace Fuel Injection Computer.
Spark does not ignite fuel. Replace Ignition Computer.
Console display shows Have vehicle and checkbook towed
“Computer Malfunction.” to nearest authorized Varoom dealer.

Well, it’s nice to know that one out of the five problems can be solved by the car’s
owner. But personally, I prefer driving a car that can be fixed and troubleshot by
ordinary human beings. Go ahead, ask me, what do I drive that fits that description?
A 1968 VW Beetle. (My wife has a newer car; she has a 1969 Beetle.) If it doesn’t
run (which is a fairly rare occasion) I know how to troubleshoot it. Do I look at a
table? Yes, but not in a book. I look at a table inside my head. What if I suspect the
carburetor or fuel pump? I pour a tablespoon of gas down the carburetor’s throat. If it
fires and runs and then dies, I know that I can provide gas, but the carburetor can’t.
Then there are a number of things I can do-such as holding a gallon of gas on top of
the car to provide fuel. No pump needed. I haven’t had to do that, but I’ve seen a
friend do it.
If I suspect the spark, I always have enough spare parts that I can check the spark,
check the timing, swap in spare points, rotate the distributor, whatever is needed. I
keep spare parts in my car, to help a friend when I spot a VW broken down along the
highway. I even keep a spare envelope (SASE) in the car so if I try to help a guy and
we can’t fix it, and we can’t figure out why, I give him the envelope and he can mail
it back to me to tell me what the problem turned out to be.
Last year, I got a letter back from a guy who “broke down” along Bayshore with a
newly-purchased 1970 VW Bus. At the time, we couldn’t figure out what was wrong
with it. In the letter, he explained that the gas gauge always read 314 full because it
was broken, which was why he ran it out of gas and didn’t know it. Unfortunately,
the guy he bought it from wasn’t helpful enough to warn him.
So, if I keep on driving this basic car forever, I will know everything I need to