Whines and whistles can be loose windings on the line output transformer also the deflection coils on the tube neck. Modern stuff is potted to a better standard you may have to live with the noise. For earthing the EHT cap on the tube we used to (TV workshop) use a wire to chassis/tube surround and that wire to a screw driver.. push under the rubber cover along the glass to discharge, you hear a small crack, hold for a few secs, then its safe. Dave Caroline

--- On Mon, 2/23/09, John Floren <slawmaster at gmail.com> wrote: If it's been sitting for a month, you're probably good. I've never seen one hold a charge that long. In all honesty the hype and the fear of working on monitors is especially overrated. Yeah, there's thousands of volts in there. If you get bitten by it, it'll hurt like hell. But it's not going to kill you. And monochrome terminals use a lower high voltage than the average color television. To safely discharge the tube, get a flat blade screwdriver, and a cliplead. Clip one end of the cliplead onto the metal shaft of the screwdriver, and the other end onto the CHASSIS ground of the monitor. Basically, you want to clip it to the metal mounting band around the picture tube. Hold the screwdriver by the plastic handle and carefully slide it under the suction cup until you hit the metal clip. If it's still got a charge, you'll hear a nice ZAP! If you do get a zap, pull the screwdriver out, then put it back in and do it again. This time, you should hear nothing - but probably a small click. The first time doesn't always get it all. After that, you should be safe - at least from the picture tube. Other large caps in the terminal (and in the linear power supply of an ADM3A) might still be able to bite - discharge those by shorting them with a screwdriver. There is nothing magical about a picture tube that makes it dangerous - it's acting as a capacitor. The inside conductive coating of the tube forms one plate, the glass forms the insulator, and the conductive coating on the outside (aquadag) forms the other plate. You're shorting this capacitor out with the screwdriver, discharging it's stored charge. It's a good idea to perform the discharge ritual any time you go to disconnect that anode cap. Even if the thing has been sitting for a month, it doesn't hurt to go through the motions. Make it a habit, and you won't get bitten. And even when you do make it a habit, sooner or later, you'll forget, and pull the cap off a charged tube. It'll zap you, and it'll hurt. Your arm will feel tingly for a couple minutes. Then you'll move on with your life, and you probably won't forget again :) -Ian

A are CRT will hold its charge for a very long time. The capacitor is the inner and outer aquadage coatings with the glass of the CRT flare as the dielectric, and glass is an excellent insulator. But you don't ahve a bare CRT. In a number of cases there's actually a leeder resisoptr inside rhe flyback (more common in colour monitors, where it forms a potential divider to get some other CRT electrode voltages). In which case the thing will discharge in well under a minute in my expeirence. Also, the CRT beam current in nromaly operation will tend to discharge the CRT at switch-off. If the terminal/monitor was displaying a normal image when you turend it off, it's unlikely much charge remains. But if the screen was blnak due to a fault (video amplifier, CRT heater, etc) and there was no beam current, some charge could well remain. I would certainly recoemnd against doing that, for all some manuals seem to recomend it. Apart from a slight risk of damaging the CRT itself (it's posisble to damave the internal connection between the inner aquadag coating and the anode connector), it's much more likely that the current spick will indirectly cause damage to ICs all over the terminal. I use my EHT meter to discharge CRTs. It's got an intenral resistance of 800M, and thus discharges them safely and fairly quickly. But I guess not everyone has that sort of instrument. I would be suprised if what you discharged was the EHT. The only place you'l l find that is on the final anode connecotr on the side of the CRT flare. It's not on any PCB tracks, etc. Unless you're actually working on the CRT/flyback, there's little risk of getting zapped y the EHT itself. -tony