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Old 01-13-2014, 01:49 AM
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Electronic M Electronic M is online now
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Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
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IIRC your only previous restoration was on an electrostaticly deflected set. With that in mind, there are some safety concerns on this to be mindful of. Hot chassis sets have one leg of the AC line connected to the chassis so if you touch the chassis and anything with a path to ground you are liable to get a nasty shock. You should look into getting a line isolation transformer to isolate the set from the direct DC path between the chassis and line that it has. Keep in mind that if you use any AC powered test equipment with the set while it is running without powering the set through an isolation transformer you may cause severe damage to your test equipment and or TV.

Next up is the HV system. Magnetic deflection sets tend to have much higher HV than electrostatic sets, and also tend to store that HV much longer. The coating on the outside of the CRT is grounded(or at least should be if nothing is wrong). That conductive coating along with the glass wall of the CRT and an internal coating form a capacitor. That capacitor integral to the CRT filters the HV, and also can store it for long after the set is powered off. Avoid working inside the HV cage or around the anode connector on the CRT bell when the set is on or the HV has not been manually discharged. Getting hit by HV, even stored charge from the CRT, is usually not fatal, but it can hurt pretty bad, and if it triggers your reflexes you can do a great deal of damage to your self and the set as your arm jerks back.

There are two ways to manually discharge CRTs: resistive discharge, and direct shorting. Resistive discharge is the better method and requires an HV probe (or some kind of homemade resistor probe) to bleed down the voltage over about a minutes time or less. Clip the ground of the probe to the chassis, and touch the tip to a bare HV contact and watch for the meeter to drop to 0.
The dead short method involves taking a WELL INSULATED screwdriver and using a jumper to connect the metal shaft to the chassis then touching the metal tip of the screw driver to a HV contact...If a loud POP is heard you had HV before the pop and have successfully discharged it. The downside to the short method is that after discharge the HV anode tends to 'recover' charge after a while and return to having HV on it(I'm not sure why though).
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