SD tech , you said you could give me start to

Nov 02, 2009

1. UNPLUG TV SET.
2. Remove back cover of TV set.
3. Remove entire front speaker grill on set(it pulls off and may resist being removed)
4. Locate and unplug speaker wires (they are plugged into the main circuit board).
5. Locate three cables with wires that come from the Front keyboard—two of them have to be unplugged from the main board(all plugs are different sizes but note where they go)
6. Remove 2 long philips silver machine bolts from the front of the set (behind the grill).
7. Remove 4 more in the back of the set; two are located at the extreme back edge of the plastic frame and hold the chassis down; two more are located on either side and also go straight down; note which are which and set them aside.
8. Using gloves pull the entire metal box (it is called a light box) out of the set; there are hand holds on either side—careful as the metal has sharp edges.
9. Remove the box from the set and locate the two Convergence IC chips; they are located on identical metal heat sinks with fins and they should have the STK-392-110 number clearly printed on them in white (they are black)
10. Turn the light box over on its side and UNSOLDER ALL 18 PINS ON EACH IC. It is a good idea to apply liquid solder flux to the pins on both chips now. I recommend using a de-soldering braid for this—get all the pins completely de-soldered.
11. Inspect the dozen or so light blue resistors in front of them; most are marked 2.2 ohms—if any are white in the middle you will need to replace them at the same time; best way is to check all of them like checking a fuse----they protect the set if one of the STK’s shorts in any way.
12. With the STK’s completely unsoldered turn the box upright and remove the two screws on each IC. If the chips have never been replaced you will need to tap them loose with a putty knife or flat bladed screwdriver.
13. Remove both IC’s.
14. Apply heat sink grease to the two new IC’s and install them one at a time; this part can take some time and it is important the pins on the new IC’s are perfectly straight---once you get them in, Hand tighten both the screws on each IC---do not use a screw gun—you can strip the screw holes out. Clean the bottom of the circuit board where the chips were soldered with some denatured alcohol and apply liquid solder flux to all the pins.
15. Presuming you have already found/replaced any bad resistors turn the box back over and solder carefully both of the two new IC’s in, --do not short any of the pins to each other when you do this and when you are done it is a good idea to take a close look at both to make sure all pins are soldered and not touching each other with soldering you have just done. I suggest you do clean the pins on the bottom of the circuit board again with denatured alcohol.
16. Slide entire light box back into the cabinet.
17. Reconnect the plugs you removed when you removed the box. At this point take a lens cloth or a paper towel with glass cleaner sprayed on it and clean the three large black lens-if they are dusty the picture will be darker and not as clear as is should.
18. Position the box so it is all the way in place and none of the wires or plugs are pinched.
19. I usually at this point turn the set on before I replace the Six bolts that hold it in—2 from the front and the four in back----this way if you have a problem you can remove the box faster.
20. If the set comes on and now has normal Convergence go into the customer menu and adjust the convergence in the multi-point mode----CAREFUL! THE FIRST OPTION this set usually offers is a green cross in the middle of the screen—do not adjust Green!
21. Once you have the Red and Blue in the center adjusted find the second convergence mode---it will give you 8 or nine points on the screen with instructions on how to change from blue to red---use the original remote with the thumb wheel or cursor buttons to adjust.
22. NOTE: SOME of these sets need to have the Convergence adjusted in first: full/4:3 and second in the other two zoom/wide zoom and third on the HD input with a HD signal coming in. There is also an option at this point to go into the Technical menu and fine adjust the convergence all over the screen—if you need this I can give you instructions based on the model you have—most of the time adjusting the set in the customer mode will produce a good result.
23. I know all this may seem complicated to you, but this repair should take about an hour or so and just take your time when you get to adjusting the set.
24. If all looks good turn the set off and Unplug it; install all 6 of the chassis bolts back; replace the back cover and the Speaker grill and plug the set back in.
25. You may find it useful to go over the convergence Adjust again—to get all the points as good as you can. There is a hidden Tech menu that will allow a finer adjustment of the entire screen----it is somewhat difficult to access and there are a lot of buttons on the remote that then do different things.
26. Most of the time adjusting in the customer menu will give you a very acceptable picture.

Nov 02, 2009