Question about Mitsubishi WT-46809 46" Rear Projection Television
I THINK MY TV IS EXPERIENCING A CONVERGENCE PROBLEM AT TIMES. WHEN I TURN THE TV ON INITIALLY, THE PICTURE IS FINE FOR ABOUT 2 MINUTES. THEN THE CONVERGENCE GOES OFF AND THE PICTURE APPEARS 3 D LIKE. THE PICTURE AND CONVERGENCE EVENTUALLY CLEARS UP ON IT'S OWN WITHIN 10 - 15 MINUTES. I'VE TRIED CORRECTING THE CONVERGENCE BY RESETTING TO FACTORY DEFAULTS AS WELL AS MANUALY COLOR BY COLOR. WHAT'S CAUSING THIS PROBLEM? THIS HAS BEEN OCCURING FOR OVER A YEAR. ANY ASSISTANCE WOULD BE APPRECIATED. CMOORE
I had the same problem. The issue may be the same although I am not sure the powering off is related to the convergence issue. This is what I did: 1. Order the STK392-570 convergence IC and heat sink thermal transfer paste( I silicone based)..(make sure it is a reputable company so you don't risk getting bad components, I got them from an electronics supplier in MD) 2. UNPLUG YOUR TV AND ALL COMPONENTS!!!! 3. Remove the back cover and black plastic cover. (retain all parts) 4. remove the retaining bolts and screws on the black plastic tray (they are on the sides verticle mounted and front center as you are looking down on the tray.) This allows the tray to slide out like a keyboard on a computer desk. DONT PULL IT OUT YET!!!! 5. Just above the boards there is a shade board that slides out. Carefully pull it out. 6. You will have to unplug all cables ON THE BOARDS except for the RED ONES ON THE FAR RIGHT and provide tension relief for the cables by carefully unraveling them. The cables are marked on the connector and match to the markings on the board (I.E. KM, all connectors are marked with a two letter designation) Just disconnect the cables from all the boards and nothing elese. 7. Now carefully slide the tray about half way so you can see the contents of the entire center board. This is the board you need. Look in the back center of the board. There is a really large heat sink. The ICs are on the back side of this heat sink. They are held in place by a retaining bar that sandwiches the heat sink to the ICs. 8. There are some connectors on three sides of the board that are flat and white. CAREFULLY ....AND I MEAN CAREFULLY pull the left (as you are looking at board) ones up and disconnect from the center board. The ones on the right (I think they disconnect from the right board). 9. Unscrew the board from the plastic tray. There are a lot of them around the perimeter and center as well as the ones that hold the heat sink onto the board ( they also hold the board onto the tray.) You have to remove the "sandwich bar" (refer to 7)in order to get at the screws that hold the heat sink to board. (you have to unscrew them. 10. There is a box shaped cover on the left front part of this board that is screwed onto board and is also part of the retension to the plastic board, remove it to. (always remember to be careful when tugging, unscrewing, ect as it could result in breaking somthing) 11. There are black plastic tabs to the rear of the board. Unhook those and CAREFULLY lift and pivot the board forward and then up and out. 12. Now comes the easy part. You may have to pry the heat sink from the ICs carefully because of heat sink paste. Clean off the heat sink (dont use cleaner, just wipe the old grease off) 13. Use a good soldering iron (PACE, regulated, good desoldering iron) The temp just needs to be high enough to heat solder. 14. MAKE SURE YOU REMOVE THE CARD THAT WE TALKED ABOUT EARLIER that is in the front left of the board. You dont want it to break. Turn the board over so the chips are facing down. Take the desoldering tool and put it over the pins and in a circular motion until it heats the solder and push the sucker button. Do this to all of them that relate to the ICs. DONT KEEP IT TOO LONG ON BOARD. once you have done that to all pins, gentely tug on the chip wiggling it out. (carefully!!!!!) if you feel resistance desolder a little more. Make sure your desolder device is giving enough suction. 15. Now solder them back on and make sure you dont create any cold solder joints. This would be bad!!!! 16. Apply a decent amount of thermal heat transfer (grease, goo, ect) Make sure you do this or bad things will happen. You need this stuff. You can get it at radio shack. 17. Now put it back together and hurray you are done... Hope this helps... GOOD LUCK DJ
Posted on Jun 23, 2007
This kind of problem ussually starts by being intermitant and the first thing to try is to resolder all the pins in the convergence IC's , they create a lot of heat and are mounted on heat sinks for that reason but after a while the solder cracks and it does not make a good conection,down the road they migh need to be replaced but for now lets hope they only need resoldered as well as many other overheated areas in the chassis.Let us know if you need more information.
Posted on Nov 06, 2006
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