Hi,

Long Email Alert - hit the delete button if you want to now.

Another thing to look at are capacitors. Electrolytic Capacitors are notorious for drying up in ALL Electronics. One of the first things to look for are capacitors near heat generating components (examples are...

1) Any Capacitor near a heat-sinked device
2) Horizontal Output
3) Flyback Transformer
4) Vertical Output
5) Pincussion Driver & Transformer
6) Audio Output IC
7) Power Supply components
8) Large heat-dissipating resistors
9) CRT Cathode/Grid drivers & resistors on the CRT socket card

Aluminum Electrolytic Capacitor have an Electrolytic paste inside and the high temperatures surrounding them plus no decent way to remove the heat causes the Electrolytic to either dry out and the capacitor loses its capability to store energy or the losses due to high Equivalent Series Resistance make it ineffective. To save cost, manufacturers usually install 85 Deg. C temperature rated capacitors. They should use 105 Deg. C rated capacitors in most locations.

The electrolytic also drys up because of high ripple currents in the capacitor (under-rated for the application to 2 cents - they expect them to fail after 4 years - sort-of encourages us to upgrade to new "technology"). In this case, the heat generated actually boils the electrolyte and the safety vent in the construction of the capacitor opens to expell the gas and the electrolyte exits through the vent. This can be seen as residue on the circuit board (often conductive - causing problems with other circuitry), that the small Panasonic SMT can
Capacitors are know for - they are called "fish Caps" becuase when someone opens up a product that has some of them that are bad - it often smells like "fish".

A quick identifier for these is that the top will be bulged or the outside wrapper will be "shrunk" around the top of the capacitor (others will have more of the plastic on top). The ones most prone to failure are the capacitors that are over 50V (the higher the voltage, the higher the liklihood of it being bad), because they are used for filter capacitors and usually have high frequency ripple currents that stress the electrolyte paste dielectric and then are further compromised by locallized heat sources.

If he wants to keep the TV, and you want to help him, you need to replace some of the capacitors. You will need to aware of some safety information FIRST, so read all of what is below, BEFORE YOU START.

*** Caution and Disclaimer *** If you have not been inside a TV or exposed to high voltages, I advise you to have it serviced by a qualified Service Technician. The information here is my own oppinion only for "entertainment purposes" and I accept no liability for injury caused by following any of this information.

Always work with one hand in your pocket (use only one hand while working near high voltage to prevent the current going through your body from one hand to the other) on an insluated (ungrounded), surface. Many people have been injured or killed by being careless around high voltage. Not always by the electrical shock, but, by being thrown into something by the convulsing of the body muscles when excited by the shock.

Do not strike or scratch the Cathode Ray Tube (CRT or picture tube). It is constructed with a vacuum inside and being a large device, if the vacuum is compromised, the CRT actually implodes sucking all of the glass inward and then expellinging it EVERYWHERE as glass shrapnel causing great injury. ALWAYS have safety glasses on when working near CRTs and exercise extreme caution. Limit the number of by-standers, they could be injured too.

The CRT is actually a large surface Glass Dielectric Capacitor. There is an inside coating of auqadag (a sprayed metal coating) that attaches to a metallic button on the bell shape of the CRT. This inside coating is called the High Voltage Anode connection and is also the positive plate of the capacitor. There is the physical Glass material construction of the CRT bell, which is the dielectric of the capacitor. There is also a metallic spray coating black soot looking coating on the outside of the CRT. The outside coating is the negative plate of the capacitor. The negative outside coating is usually connected to High Voltage Ground by a spring wire that goes around the CRT bell or the CRT frame. The CRT High Voltage is used as a post accellerating potential to pull electrons from the CRT gun to the faceplate phosphors (what we watch). The CRT being a capacitor is also used to filter the high voltage.



Before you do anything inside the TV, un-plug it and leave it off for a day.

Remove the back cover, connect a long known-good clip-lead (check it with an Ohmeter before you use it) ** One hand in your pocket **, to the metal band spring wire that surrounds the back of the CRT or attach it to the metal CRT attachment frame. Attach the other end to an insulated-handled long screwdriver.

** One hand in your pocket **, - visually - locate the High Voltage lead wire going to the CRT. This will attach to the CRT with a rubber button cover. Using the screwdriver with the wire attached and already connected to the CRT ground wire or CRT mounting frame above, slide it under the cap (being careful not to scratch the CRT). Prepare yourself for a small audible "snap" from the high voltage arc discharge - so that you are not startled and injure yourself. Leave it shorting for 30 seconds.

** One hand in your pocket **, use the screwdriver blade to lift the cap some and use a flashlight (use the other hand too) to locate a mechanical clip or double spring wire clip to the CRT Anode attachment. Use the screwdriver to lightly push on the attachment to remove it from the lip of the CRT Anode attachment. Use the screwdriver blade to do the same with the other spring wire clip to remove the cap. Remove the screwdriver from the clip-lead and attach the clip lead to the CRT Anode connection to continue the discharge (they can self re-charge to a lower voltage). Leave the clip lead there until reassembly - but, remember to remove it when you reassemble the TV.


If he wants to keep the TV, it's a good idea if you open it up for anything else, take detailed pictures with a digital camera of the above areas, find the capacitors in those areas that are suspect (by the way that doesn't mean ALL capacitors in the TV will be bad, just those suspect near the heat generating devices), note the value and polarity of each component (the stripe down the side is negative - by-the-way - I have seen NEW capacitors that actually have the strip being (+)), and unsolder them. Take them to a GOOD (not Radio Shack, they won't have them), Electronics supply house (Capacitors are usually cost less than $2.00 each - you may replace around 15 in a typical TV), and purchase 105 Deg C capacitors to replace them. Be sure to notice that the Vertical Output coupling capacitor may be a Non-Polar capacitor, be sure to get one that is non-polar if it is.

While you are there, check all high temperature connections for cracked solder or heat stressed fractures and connections. Re-solder those with 60/40 rosin-core solder (never acid core for electronics work). Many resistors, transistors, MOSFETs, Diodes, transformers, capacitors, inductors, etc. generate lots of heat and compromise their solder joints over time. Check grounds solder connections too.

Also check the small value resistors coming from the Flyback or Power Supply areas. Thse will be usually less than 10 Ohms and they are used as current limiters and fuses when the capacitors dry-up as the ripple currents are high (by not being filtered as well), voltage goes down - still need the same power - so, current goes up, stresses or blows the resistors).

It might also be a cracked PC-Trace too (even on the push-button switch panel), look for that as well especially if the TV has had rough mechanical treatment.


Re-assemble after you have done the above things, be sure to remove the CRT shorting clip-lead. Re-check everything before the cover goes on. Power it on and see if that fixes it.


Good luck, hope you can find the problem and wait for the next thing to break.

Ross