Richard Clark wrote:
On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote:


I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line.


Hi OM,

My very first EE professor (also an engineer at the HP division in
Colorado Springs) taught us the merits of designs meeting the
expectations of Mad Man Muntz...he would snip out
components until they lost the picture, it would roll, or the sound
would go dead. Then he would suggest they put back in the last
snipped component.

He discovered his TVs didn't need synchronization circuits because his
market was in urban cities where the signal was so powerful as to
provide enough level to be self-syncing. I know, because I fixed many
of those TVs that eventually found their way into the Burbs, and were
forever rolling unless you found the sweet spot on the horizontal or
vertical adjustment (always in the back).

Yes, I've heard the tales of M. M. Muntz, but apparently so had the head
designer at the audio mfr I worked at. They had a VCA circuit using a
well known VCA chip. The data sheet notes mentioned a small value
capacitor across two pins for stability. The designer discovered his
circuit would work just as well without the cap and thus left it out of
his design, so far out that there weren't even traces or pads to put the
cap in should it become necessary (you can see where this is going,
no?). The VCA vendor outsourced fabrication of the chip and all of a
sudden the noise level of the VCA circuit would jump about 70 dB as the
fader reached the bottom of travel, not desirable in an audio
application. I spent a little time perusing the data sheets and our
schematics, noticed the cap omission, soldered a cap across the pins of
an offending circuit and within the hour we had the assemblers tack
soldering caps we bought at a local electronics shop (not RS) onto
assembled modules. The designer's comment was 'Well, it worked for
quite a while...' Later we found customers with similar noise level
jumps using pre-outsourced VCAs. Yes, they saved a few pennies on each
module but lost about two dozen customers when they figured out what had
been left out of their very expensive audio equipment.

When I started at that place I was told not to make suggestions
regarding modifications of existing designs lest I offend the managing
'engineer'.