art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art


How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.