Question about Toshiba 50HX81 50" Rear Projection Television

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CONVERGENCE? I have the dreaded convergence problem. I noticed that the blue line is curved at the bottom and seems to be lower on the left side of the screen. When trying to use the manual adjustment I have noticed that the Red can be moved up,down, left and right. When trying to adjust the blue I can make it move left and right but will not move up and down. I just replaced both of the STK392-110 IC's last night. The condition is exactly the same as before. I did not seen any burnt resistors,cracks or other hot spots. This TV is 6yrs old and has been working great until this. Could there be a problem with the CRT? Is there a good way of checking them to confirm? Any and all help is very much appreciated

Posted by GLENN HOUSER on

  • GLENN HOUSER May 21, 2007

    Thank you for your help.
    I did find a burnt resistor. I replaced that resitor and now instead of the left (facing the front of the TV) end of my blue line curving downward it is curving upward and seems to be somewhat squiggly at the end. The blue line can be moved in all directions now and have tried the 9 point convergence adjustment and still cannot get rid of the curved blue line.
    I have checked the rest of the resistors on the convergence circuit board and all seem to be in the proper range.
    I even tried to move the rings on the Blue Gun.....still have the curve....
    Is it possible tha a messed up one of the IC's when powered up with the open resistor? How would one determine that?
    Since the Green, Red, and Blue connectors are the same, would it be possible to swap the connectors at the circuit board to isolate a possible bad Gun???

    Would any of these tests or questions be covered in the Service Manual?

    Thanks again for any and all help.



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You can not tell anything about those resistors by sight get an ohm meter and test them. Disconnect the three plugs going up to the Yokes first though or you will not get an accurate reading. Check the resistors around the blue yoke plug closely this is where you will find your problem.

Posted on May 17, 2007

  • Anonymous May 22, 2007

    well if the blue can move in all directions then you are probably fixed. does the blue move in both directions at all nine points? but you can not get close enough? If this is the case you may need to do the alignment in the service menu. The possibility of damaging those IC's is remote but I will never say impossible in this line of work. Swapping the yoke plugs will isolate the yokes but your problem is not the tubes and i really doubt the yoke, that is VERY uncommon. Major adjustment in the service menu is not that uncommon after an amp job. I would move the rings back they really shouldn't be moved, they are basically used for centering so use the center cross in the customer convergence menu to adjust them back. To enter the service menu, mute the TV (push it twice if it has the half mute feature) and then press and hold the mute button again on the remote, while you are holding it press the menu button on the TV. You will see a small "s" appear in the right corner of the screen. now press the menu button on the remote and the "s" will dissappear on the right and you will see an adjustment on the left, probably "rcut". Now press the number 7 (NOT ANYTHING ELSE!!). You should now see a large cross hatch covering the screen with a curser somewhere. The number 5 will freeze the curser for adjustment or start it flashing to move it to the next spot. While it is solid you can press the number 3 to change colors. and press 8,4,6,2 to adjust the selected color. While it is flashing 8,4,6,2 will move the curser around the screen. Only adjust the blue and notice that areas around the spot you are adjusting are also being effected. It takes a little patience and a lot of getting used to as you can adjust one spot and bring another out so you have to correct it and then go back to the original spot and over and over again. do yourself a favor and beginm with small changes. Good luck and let me know how its coming.



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