TV Fault Diagnosis. (Pictures) Admin, I have posted this in "overclocking & hardware" also in "Modding & electronics." Please delete if you don't think it is appropriate. Monitor diagnosis. I make no claims to being an expert. But I have been doing this line of work for over 25 years. When I first had the idea to write this it was going to be a simple guide. It Grew! Televisions & Computer Monitors share many similarities. As such, the following article contains reference to both. Generally speaking, what applies to one applies to the other. This is by no means a comprehensive list of faults, But should cover the most common faults. I have the intention of adding or removing material as I see fit. Dangers: There are many "bightee's" inside a TV or monitor case. Delve inside entirely at your own risk. The major dangers, apart from electrocution, while switched on are. a: Getting zapped from a charged electrolytic capacitor. The main filter capacitor can store a substantial charge for days, if not weeks.It has a charged capacity of about 350 volts. They hurt.The capacitor can be discharged (obviously power off & disconnected) by shorting a 220 ohm 5 watt resistor across it for 5 or 10 seconds. b: Getting belted by the charge stored in the picture tube. Stay away from the lead (with the suction cup on it) that goes to the picture tube.The pic tube can store over 27,000 volts.Once again this charge can be stored for days or weeks. c: Injury from an "Implosion". The glass on the back of a picture tube is very thin. It is very easy to break the neck off the pic. tube. Usually this results in no more than a quick "Hiss" as the outside air gets into the tube. But I have heard stories of the glass shattering, being sucked into the tube, then bouncing out with great velocity. Here are some fault conditions & possible causes. 1:- No power. Is the power switched on? Is the power light on? If not it is possible that it is a fuse, but not very likely. Fuses usually blow for a good reason. Do you have high tension? When switched on at the power switch, monitors usually make a "SSST" sound. This is the picture tube energising. Inside the glass, it is recieving approx. 27 Kv. (Kilo Volts) If you hold your arm. (or something else hairy,) in front of the pic. tube when you turn it on, you will feel the hairs stand on end, due to an intense static charge inside the tube. This can sometimes be followed by the sound of a relay. This is the Degauss cct kicking in. If you here & feel this it is reasonably safe to assume that (most) of the power supply is operating. 2:- Picture comes on for a while, but gradually fades away,sometimes the pic. will fade back on for a while & then fade away again. This is an indication of a "dry joint" in the heater cct. For the electrons to be emitted properly, their need to be a "heater" at the back of the tube. That is the orange glow you see around the neck of the tube while it is running. The heater operates off 6.3 volts, usually supplied by the power supply in monitors, & usually from the LOPT (Line OutPut Transformer) in televisions. 3:- Screen comes up intensely white.Sometimes with fine white diagonal lines through it. Probably a fault with the ABL (Automatic Beam Limiter) part of the cct. The electron guns are being overdriven. 4:- Screen comes up intensely Red, Green, or Blue, with fine lines diagonally through it. Possibly a shorted picture tube, but probably a faulty drive transistor, or accociated drive circuitry. 5:- Screen intermittently drops one colour, or one colour missing. a: Faulty cable.Monitor cables frequently fail around the HD15 plug (High Density 15 Pin Plug) b: Possibly pic. tube again. But more likely a faulty drive transistor, or accociated drive circuitry. Normal colour bars. Red missing. Green missing. Blue missing. 6:- Vertical collapse. Sometimes intermittent. Sometimes only partial collapse. A solid white line across the screen. Fault with the vertical deflection circuitry. Many causes, Dry joints, elecrolytic capacitors, Vertical output I.C., vertical Oscillator etc. 7:- Horizontal collapse. The same as a vertical collapse but the line goes down the screen instead of across. This is not often seen because usually the device dies as soon as it happens. If you see a solid white vertical line on your monitor or TV, turn it off IMMEDIATELY, & have it repaired. If it is still running, not to much damage has been done. If you are very lucky, you may find a dry joint around the LOPT. If the set no longer runs, the horizontal stage has probably blown up. This is serious repair stuff. Probably not worth repairing. Far too many causes to list. 8:- Picture geometry faulty at the sides. Pin cushion problems. Because a CRT (Cathode Ray Tube) tries to make a rectangular picture from a pin-point, also the characteristics of the tube, Circuitry is required to try & straighten out the sides. Pin-cushion problems will cause "bowing" of the sides,or picture distortion. on the sides. 9:- De Gauss. Picture tubes being electro-magnetic devices are effected greatly by stray magnetic fields. Magnets, speakers or even turning the picture tube on its side, while running are enough to upset the purity of the screen. If you have green, red or blue patcheson the screen. It is because of either a problem with the automatic Degauss cct, or the automatic degauss cct is unable to cope with the degree of induced magnetism in the screen. Usually a sweep with a degaussing wand is enough to rectify the problem. A degaussing wand in action. This is a superb image of what misconvergence looks like. You can see that the RGB beams don't line up, so you get three distint images, in red, green & blue. The most common reason most electronic devices fail is due to electrolytic capacitors being "cooked". They can only stand so much heat for so long.This is a common occurrance. One of the power supply signal capacitors, mounted up against a radiator.(Oops, I mean heatsink) Do you think they know what built in obsolescents is? I hope this is of interest.