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 works out for you and give you some ideas. Pls post again how things turn up, good luck and kind regards.
on Aug 12, 2007