And a missing transistor i need scheamatic componants

Have you replaced the IC , Q2 and Q2?

• Check the Differential Inputs ( IC1 ) and sorrounding components


• Check the Driver Stages


additional guides or suggestions:

Cross wired speakers and blown power transistor.



Beware also of counterfeit Power Transistors

the tv have a fault in the power supply circuit or horizontal circuit check the regulator transistor or ic in your power supply and other components there.check the horizontal output transistor in the horizontal circuit and other components around replace what ever component you find faulty and components associated with the faulty component.good luck.

check the ic in the color circuit or the resistor that connects to the collector of the kine transistor.these components can be faulty.probably it is a module so you might need to replace the module that has on the color circuit check the transistor also.good luck.

hello,
This is a vertical deflection problem - possibly a bad capacitor, bad connection, flyback/pumpup diode, or other component. None of these should be very expensive (in a relative sort of way).

If the symptoms change - particularly if they become less severe - as the set warms up, a dried up electrolytic capacitor is most likely. If they get worse, it could be a bad semiconductor. Freeze spray or a heat gun may be useful in identifying the defective component.

It is often easiest to substitute a good capacitor for each electrolytic in the vertical output circuit. Look for bad connections (particularly to the deflection ports), then consider replacing the vertical output IC or transistor(s).

A missing power supply voltage, defective vertical output IC, or a component associated with it is likely bad. A bad connection or blown fusable resistor may be the cause of a missing power supply voltage.

The following are NOT possible: CRT, flyback (except possibly where it's the source for a missing voltage but this is more likely just a bad solder connection at a flyback pin), tuner where the controller is at fault - see the sections on these specific brands. I am just trying to think of really expensive parts that cannot possibly be at fault.
Hope this will help..

couple of points to note.

Without a model / revision number it will be antibody's guess as to what the transistor is.

On most boards there id and ID No. eg. t34 or tr99 or something similar.
That too would be very useful if you have it.

Sometimes manufacturers leave out components because they found they were not needed or maybe found a cheaper way to do the job of that component

So if it was intentionally left out then putting one in could well do more harm than good.


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if sb +5 is ok then check one by one these component :-
check main swithing transistor for open
check diode, capesetor and 3.3 ome resitor it may be open after then check
+ 12 to +18 volt for pwm ic and ,

if votage is not missing then change pwm ic

Hi,

Initially, pls check D854 on the Power Supply/Logic board. It is a dual diode. If you would prefer board replacement rather than component level repair, this might be of help. This of course would require a fair familiarity of electronic components/circuitry and safety procedures, use of a DVM and a soldering iron. It would be to your added advantage access to a service manual or at the very least a schematic diagram with voltage readings. Should you be uncomfortable performing a DIY (do-it-yourself), perhaps your best bet would then be to seek the services of a qualified professional.

This is of course in addition to checking the usual, power cord, fuse, outlet etc.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information. Good luck and kind regards. Thank you for using FixYa.

- A bended color pin at the VGA connector. (If pin one is bend then there would be no red color)

- A defective VGA signal cable. If the internal wires were broken then there would be missing colors. You can check if the signal cable is good or bad by doing a continuity test using a multimeter.

- Dry joints in the CRT board such as in the CRT socket pins, video pre amp and driver IC and even at the connector pins. In fact this problem contributed about 80% of Monitor color problems. Applying fresh solder would usually solve the color problem.

- A defective IC either in the Video Pre-amp or Video Driver IC.

- Faulty components in the CRT board. It could be a shorted driver transistor or even electrolytic capacitors that the ESR reading had shot up!

- A bad CRT socket. Sometimes decayed glue could cause the internal pins rusted and thus affecting the colors. Replacing only the CRT socket would definitely solve the problem.

- A weak or a defective picture tube (CRT tube). Yes, I do came across one of the electron gun (most probably the cathode materials had used up) in the tube faulty caused a missing color in the screen. There’s no way to repair this type of problem-the only way is to replace the CRT tube.

- In the newer type of Monitor, color setting is save in the EEPROM IC . Thus, if the EEprom data is corrupted, you would also get a missing color! The only way to repair it is to reprogram the IC or use a soft jig to tune it back the color setting.



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Hi, This sounds like a color driver problem with the RED. I will assume that the blue is good since yellow will only be present if the green and blue are both ok. Below is a copy of my response to a similar post at http://www.fixya.com/support/t181021-zenith_a25a11d_no_red_color "...If you are comfortable working with a soldering iron, a continuity (VOM) multi tester and a fair knowledge of electronic components, then perhaps you can repair the missing color red. You have to open the unit, expose the small printed circuit board that is attached to the small end of the picture tube. There will be many components present but you will need to focus yourself on three (3) transistors that are bigger than the others sometimes with an aluminum heatsink. It is also possible that instead of 3 transistors you will have one power IC. In any case these control and provide the drive for the 3 colors of your picture tube: red, green and blue. One of them is either dead or suffers from cold solder to any or all of its pins/legs. You have to visually inspect the solder joints of these big transistors/IC and determine if any is dull in color, loose of simply not connected. You may even try the shotgun approach and solder each of the pins/terminals/legs just as long as you don't cross solder creating a short between pins/legs. If this works, you're set, if not: You have to check with the use of the VOM and determine which of the 3 transistor is defective. If you are familiar checking continuity of base to collector to emitter and reverse, again you're set, if not perhaps you check all three and compare which have the same reading from the same position and which is different. Pls keep in mind the transistors have forward and reverse bias readings. If able to determine defective component, desolder, replace and solder. If it were an IC, replace the entire pack. If the above would make you uncomfortable, pls ask for the services of a qualified TV repair man and explain your problem..." Hope this give too an idea. Good luck and pls post again how things are or if you need further information. Kind regards.

Hi, If you are comfortable working with a soldering iron, a continuity (VOM) multi tester and a fair knowledge of electronic components, then perhaps you can repair the missing color red. You have to open the unit, expose the small printed circuit board that is attached to the small end of the picture tube. There will be many components present but you will need to focus yourself on three (3) transistors that are bigger than the others sometimes with an aluminum heatsink. It is also possible that instead of 3 transistors you will have one power IC. In any case these control and provide the drive for the 3 colors of your picture tube: red, green and blue. One of them is either dead or suffers from cold solder to any or all of its pins/legs. You have to visually inspect the solder joints of these big transistors/IC and determine if any is dull in color, loose of simply not connected. You may even try the shotgun approach and solder each of the pins/terminals/legs just as long as you don't cross solder creating a short between pins/legs. If this works, you're set, if not: You have to check with the use of the VOM and determine which of the 3 transistor is defective. If you are familiar checking continuity of base to collector to emitter and reverse, again you're set, if not perhaps you check all three and compare which have the same reading from the same position and which is different. Pls keep in mind the transistors have forward and reverse bias readings. If able to determine defective component, desolder, replace and solder. If it were an IC, replace the entire pack. If the above would make you uncomfortable, pls ask for the services of a qualified TV repair man and explain your problem. Hope this works out for you and give you some ideas. Pls post again how things turn up, good luck and kind regards.