Page 23 - The Art and Science of Analog Circuit Design

The Importance of Fixing

The reason all this is so valuable is that it brutally tests your thinking
process. Fast judgments, glitzy explanations, and specious, hand-waving
arguments cannot be costumed as "creative" activity or true understand-
ing of the problem. After each ego-inspired lunge or jumped conclusion,
you confront the uncompromising reality that the damn thing still doesn't
work. The utter closedness of the intellectual system prevents you from
fooling yourself. When it's finally over, and the box works, and you
know why, then the real work begins. You get to try and fix you. The bad
conclusions, poor technique, failed explanations, and crummy arguments
all demand review. It's an embarrassing process, but quite valuable. You
learn to dance with problems, instead of trying to mug them.
It's scary to wonder how much of this sort of sloppy thinking slips into
your own design work. In that arena, the system is not closed. There is no
arbitrarily right answer, only choices. Things can work, but not.as well as
they might if your thinking had been better. In the worst case, things
work, but for different reasons than you think. That's a disaster, and more
common than might be supposed. For me, the most dangerous point in a
design comes when it "works." This ostensibly "proves" that my thinking
is correct, which is certainly not necessarily true. The luxury the broken
instrument's closed intellectual system provides is no longer available. In
design work, results are open to interpretation and explanation and that's
a very dangerous time. When a design "works" is a very delicate stage;
you are psychologically ready for the kill and less inclined to continue
testing your results and thinking. That's a precarious place to be, and you
have to be so careful not to get into trouble. The very humanness that
drives you to solve the problem can betray you near the finish line.
What all this means is that fixing things is excellent exercise for doing
design work. A sort of bicycle with training wheels that prevent you from
getting into too much trouble. In design work you have to mix a willing-
ness to try anything with what you hope is critical thinking. This seem-
ingly immiscible combination can lead you to a lot of nowheres. The
broken instrument's narrow, insistent test of your thinking isn't there, and
you can get in a lot deeper before you realize you blew it. The embarrass-
ing lessons you're forced to learn when fixing instruments hopefully
prevent this. This is the major reason I've been addicted to fixing since
1968. I'm fairly sure it was also Jerrold's reason for bouncing my instru-
ment repair allocation.
There are, of course, less lofty adjunct benefits to fixing. You can often
buy broken equipment at absurdly low cost. I once paid ten bucks for a
dead Tektronix 454A 150MHz portable oscilloscope. It had clearly been
systematically sabotaged by some weekend-bound calibration technician
and tagged "Beyond Repair." This machine required thirty hours to un-
cover the various nasty tricks played in its bowels to ensure that it was
scrapped.
This kind of devotion highlights another, secondary benefit of fixing.
There is a certain satisfaction, a kind of service to a moral imperative,