Monitor burning smell

Not to be funny, but a CRT monitor capacitor can hold up to 40 kV for over 48 hrs from power down. bzzzzzzzzzzzzzt!
 
wikipedia:

CRTs operate at very high voltages, which can persist long after the device containing the CRT has been switched off and/or unplugged, sometimes for years. Residual charges of hundreds of volts can also remain in large capacitors in the power supply circuits of the device containing the CRT; these charges may persist. Modern circuits contain bleeder resistors, to ensure that the high-voltage supply is discharged to safe levels within a couple of minutes at most. These discharge devices can fail even on a modern unit and leave these high voltage charges present.
 
dotVIBE said:
wikipedia:

CRTs operate at very high voltages, which can persist long after the device containing the CRT has been switched off and/or unplugged, sometimes for years. Residual charges of hundreds of volts can also remain in large capacitors in the power supply circuits of the device containing the CRT; these charges may persist. Modern circuits contain bleeder resistors, to ensure that the high-voltage supply is discharged to safe levels within a couple of minutes at most. These discharge devices can fail even on a modern unit and leave these high voltage charges present.
Click to expand...

Ah we still believe everything the Wiki says? 100% for trying and wasting time to dig this up. You can teach me nothing about Industrial or commercial electronics.

How many was killed the last twenty years by a TV when someone fiddled in there.

Honestly just pure rubbish talk by guys knowing nothing about TV repairs. No wonder TV shops rip you off.
 
dotVIBE said:
wikipedia:

CRTs operate at very high voltages, which can persist long after the device containing the CRT has been switched off and/or unplugged, sometimes for years. Residual charges of hundreds of volts can also remain in large capacitors in the power supply circuits of the device containing the CRT; these charges may persist. Modern circuits contain bleeder resistors, to ensure that the high-voltage supply is discharged to safe levels within a couple of minutes at most. These discharge devices can fail even on a modern unit and leave these high voltage charges present.
Click to expand...

I think the point is, for the money involved, it's not worth the effort or risk.
 
NoADSLyet said:
So you have done a course. Funny how many here is lacking DIY skills but yet have huge knowledge of Fall. I am sure If Allan85 cannot solder and cannot even work in his car (where the same voltage exists after the coil), he would consult someone to assist as maybe he can think for himself. Funny how many low skilled individuals that did not do electronic courses do repair TV's. Just go look at TV shops at the back.
Click to expand...
This is no joking matter. A friend of mine received a shock from a tv set a month after it was unplugged and most of the charge was already dissipated. Giving such advice to someone that may be inexperienced is very dangerous and this also applies to other devices such as microwaves which you should also actuallly not work on without a leakage detector. Yes you can do it without doing a course but these individuals get the necessary training to know how to work safely.

As said it is the high voltage capacitor powering the electron beam that can carry a charge of mutiple kilovolts even for years after it is switched off. This is very different from a car coil which releases a charge only once when the power is switched off and it's magnetic field collapses. Capacitors are made to store a charge AFTER the power is off and touching any part of the circuit that connects to it can give you quite a jilt.
 
The CRT itself acts as a capacitor. It is normally charged to about 20,000 volts, which under the right circumstances can do you serious harm.

A qualified repairman knows how to discharge the CRT prior to working on it. If you don't know how to do this, then buy a new device or take it to a repair shop.
 
bekdik said:
The CRT itself acts as a capacitor. It is normally charged to about 20,000 volts, which under the right circumstances can do you serious harm.

A qualified repairman knows how to discharge the CRT prior to working on it. If you don't know how to do this, then buy a new device or take it to a repair shop.
Click to expand...
That point was made . . . . many (6+) moons ago. ;)

Someone once mentioned a vbulletin modification that automatically closed threads after X amount of inactivity. Maybe it wouldnt be such a bad idea.
 
I'd rather take the monitor in for repairs than try repairing it myself...

Or, depending on the age of the monitor, will opt to buy a new LCD display instead.
 
bwana said:
That point was made . . . . many (6+) moons ago. ;)

Someone once mentioned a vbulletin modification that automatically closed threads after X amount of inactivity. Maybe it wouldnt be such a bad idea.
Click to expand...

Sorry, I cannot see a post which states that the CRT itself acts as a capacitor.

Just in case you and others posting here are in ignorance, the CRT is the glass vacuum tube that displays the picture, it has a bunch of wires connected to it at the neck and another wire, covered by a rubber insulator, attached near the face. Now, even if you disconnect ALL of the wires attached to it, it still retains a very high voltage charge.
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X