Hello,
I am an electrical engineer, and I know exactly how computer monitors work, and I know how televisions work as well.
Thing is I have never repaired a television or computer monitor while having it on and plugged. I just can't risk it. I never learned how to do it.
Any book that covers the safety issues regarding this kind of technology?
Are we talking CRT, Plasma, LCD, .. ?
As for CRT: Keep the left hand in your pocket such that hazardous voltage may not pass through your heart. Beware of things that may explode and threaten eyevision. Common sense goes a far way however.. You could use some kind of insulating gloves to prevent some hazards. There is also lot of toxic chemicals inside in the form of flame retardants.
Good advice. Also, I like to run a GFI on my bench outlet that powers whatever I am working on - could be a lifesaver.
Luhan Monat (luhanxmonat-at-yahoo^dot^com)
Get a heavy clip lead, and ground one end to the main chassis, which should be in common with the outside coating of the CRT. Clip it to a small screwdriver, and poke the screwdriver under the HV cap, until you feel it in physical contact with the HV contact, then leave it there.
There's also 200-300V "B+", used for deflection amps and focus and so on, use the usual precautions around them.
The safest thing to do, of course, is to have somebody else fix them. ;-)
Good Luck! Rich
With the set off! Use a clip lead connected to a flat blade screwdriver on one end, connect the other end to the "Daq". The Daq is a wire surounding the area of the CRT usualy suspended by springs. Push the blade of the screwdriver under the Anode cap (high voltage to CRT) you should hear a snap indicating the HV is discharged. Do this even if the set has been off for hours, days, months, etc... The CRT has a large capacitance that stores leathal high voltage! and yes it will recharge itself!
Testing with set on: Use an isolation transformer to power the unit. This will protect you the unit, & test equipment! Be aware of high voltages at the power supply and the flyback (HV) transformer and surrounded area. Tread safely - good luck...
I needed to move a picture tube that had been sitting (by itself) in our basement for over a year. Just for yacks, I did the clip-lead-to-the-pins clipped to a screwdriver. It drew a half inch arc off the anode connection!!!
Luhan Monat (luhanxmonat-at-yahoo^dot^com)
What about putting a piece of plywood on the floor and standing on it? Someone recommended that.
And what kind of gloves should I wear? Cotton maybe?
"rpcarnell"
** Completely asinine advice.Chassis parts of a TV set or monitor are at earth potential while other parts are at lethal voltages.
Put one hand on each - get a massive shock right through the heart.
** Even more asinine.Provides no reliable shock protection and PREVENTS you from handling small parts successfully.
A clueless Googlegroper and blatant LIAR like you needs to keep right away from TVs and monitors .
....... Phil
My advice: Don't discharge the CRT unless you have to remove the high-voltage section. Just leave the cap in place. It provides enough protection. Discharging the CRT just adds extra unnecessary risc to the job.
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Not even wrong.
Many early tv sets and some earlier monitors were hot chassis designs.
As of course, were the overwhelming majority of lower cost am radios.
They simply hoped the cheater cord interlock and the knobs stayed in place. There were very few complaints from the fatalities themselves.
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** True for the vast majority of TV and monitors in service.
Note, my comment above is written in the present tense.
** Still a few hot chassis TV colour sets about - mainly in the smaller tube sizes. They can be VERY hard to spot sometimes, particularly if of "double insulated" construction ( ie with no supply earth wire).A 12 inch, GE brand set I own, made by Thomson in Thailand, is just such a beast.
There are NO printed warnings and the metal antenna plug goes directly into the tuner module - so it must be an earthed chassis set - right ??
Wrong !!
Close examination of the co-axial antenna socket reveals small, white plastic ring around the middle and an ohm meter test shows no continuity from the outer part to the tuner module box.
Arrrrghhhh !!
The antenna socket contains a hidden isolation balun -
the WHOLE DAMN SET was live at 240 volts !!
** That means tube sets, all well over 40 years old........ Phil
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