Craig Hart was saying to Tika Carr on 02-11-97  08:08:
I got another question, since you're good with monitors.  This is
regarding the CTX CVP-5439A 14" .39dp SVGA analog (Tri-sync) color
monitor.  Since new, its made noises (which is normal) that I was
always curious about, but nobody has been able to explain technically
what the noises are from.  They are:
- power up "broomph" like a motor starting or something.  I can't
  explain it exactly, but sometimes on power up it makes a low-pitched
  noise.  Is that that Startup pulse provider you mentioned? Is that
  what is powering up?
- The old familiar "mode change tweets" - CRT tube adjusting to mode
  or scan frequency adjuster of some kind??
- The "clicks" during some mode changes (I think this is from high to
  lo res. The tweet from low to high res, or maybe I have that
  backwards). This is some kind of relay to change mode back?
I was just curious what those are.  I know if I DIDN'T hear them I'd
become extremely worried (espeically if the power-on noise didn't
happen when I turned the monitor on after its been setting more than
an hour...)
RE: High Voltage
OUCH! That tube we look at? Sheesh! Wonder why they need so many volts
to operate the screen display? May be the number of times the color
guns have to fire, huh? And how fast it has to do so (ie. scanning
frequency).
 CH> Servicing safely is a combination of:
Good advice!
I've worked on "live" computers before. You just have to follow one
rule - STAY AWAY FROM THE POWER SUPPLY! Don't touch it to "ground"
yourself (or you just may - literally - if something malfunctions).
So many installation instructions say "leave computer plugged in, but
turned off.  Touch the power supply to discharge static in your body."
IMHO, WRONG! That's asking for trouble.  Anti-static wrist straps,
which you can safely screw into a power strip's ground are only less
than $5 at Radio Shack.  I tell folks to UNPLUG the machine and use
the wrist strap when installing cards (like sound cards, memory,
modems, etc).  That is the safest.  For I think $7 they have
anti-static squares you can set a card on so you can set the card
aside while working in the machine.  Inexpensive, safe solutions.  I
wish computer manuals would stop preaching unsafe working habits.

 CH> safety devices & practices such as isolation transformers, CRT
 CH> dischargers, capacitor dischargers, eye protection, and TEST before
 CH> TOUCHtechniques.
Ah... so you DO have protective devices, much like the electric
company workers have when working on high voltage power lines?
I have been doing electronics since age 7 (23 years, about) and
soldered stuff at age 7.  I learned very early on the value of
respecting electricity. How many times I would be fascinated with the
inside of a Tube TV set (then color when we got one) when Dad had to
fix it or change the tubes. He'd always yell to get away from the TV.
After awhile he gave up and said "See this? Don't touch it or it'll
kill you..." that wasn't just a threat to keep curious kid's fingers
out of his work! And I took heed of the warning. If it plugged in,
DON'T touch the circuits. My dad did lots of repairs so I always saw
the insides of stuff. I'd look, ask questions, and learned how things
worked. I used to use the ratings on Radio Shack kits to see what I
could safely explore next. I'd do the kits and learn from them. When I
got to high school, we did a cource on house wiring. Then I learned
some more on AC electricity and from there, I knew enough to work on
AC-powered stuff. I learned the #1 rule of electronic repair:
If you are not sure, DON'T DO IT! Have someone else do it. I usually
ask someone who knows and if I still am not sure about poking into the
unit, I take it to someone who has done lots of that type of work and
have THEM do it. Either that or buy another, or (more often than not)
make do without the unit. 
Tika
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