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Ursprünglicher Beitrag von: pnauta ,


I agree with the cautions above.  The bigger the screen (distance between the cathode and anode) the higher the voltage, which can be 25 000 volts or higher.  Voltage does not kill, but current.  The higher the voltage, the larger the current that will flow through your body and affect it.  So, take extreme care.  I had years of experience, but was always on edge when working on the high voltage circuit of CRT's.

Implosion is not that likely: put the viewing side of the CRT on a stack of towels, you'll be OK.  These CRT's have to be tested before they get to be put in front of anyone's eyes, and are designed for really low pressures (vacuum).  Just don't apply any uneven pressure, and stay away of the neck because that's the weak part.

As with all devices, disconnect from power source as a first step.

There's a cable with a rubber plug or shield on top which is the culprit.  It keeps it's high voltage because there's a whole array of diodes and capacitors to get the electrons going the right way.  The diodes keep current going in one way, the capacitors work like batteries.  This cascade achieves a high voltage using an alternating voltage, and it requires extra circuitry and a risk of failure to make it discharge when the set is powered off.  There's little current needed to illuminate the screen, but as it takes some time for your CRT to actually light up, you can figure there's a lot of electrons just waiting to take a route through your body.

We used to disconnect the rubber plug on top (anode) by using two long screw drivers with good isolated handles.  As extra, wear rubber gloves.  One would touch the metal frame, one would be used to pry undert the plug, then cross these two metal rods to short out.  Another method would be to take a wire with crocodile clips and connect it to the frame on the one side and the screw driver on the other end. Pliers can be used to press together the metal clips under the rubber shield, when at least one side can be pryed loose, it will come off.  You should always try a second discharge as a final check.