I'm having the same problem as a few others with the center in good focus and the edges gradually blurring with colors bowing out of sync. This has been happening for almost a year and I have assumed the problem is a cold solder joint or loose connection. When it first happened, a light tap on the top of the set straightened everything out for as long as the set was on. Eventually the tap wasn't enough and it would happen every few minutes. I have an electronics background and decided to remove the back and check all connectors for a loose fit. I replaced the back and the set worked fine for a few weeks, then started acting up again. This time I removed the back and with the power on and rubber gloves on, I wiggled each connector I could reach until the picture returned to normal. The circuit board with the large heat sink in the middle of the set seems to be the culprit and looks difficult to remove and check solder joints, so, for the last six months I've just been turning the set on and giving the heat sink a wiggle with the glove on and the set behaves for the day (NOT recommended for someone with no experience or respect for electricity!). If anybody has determined what might be loose and on which board I should look I would appreciate the heads up. Just because the problem goes away when I wiggle the big heat sink doesn't mean that that board is at fault. Other components near by also move a little since the heat sink is so long and It's board is large and flexible. I've read other solutions that suggest removing and replacing an IC, but If the problem goes away with a wiggle, it seems I may have a related but different problem. The set is at least 4 years old, but when it's working after my "quick fix" which is getting old, the picture is as sharp and colorful as new.
I just fixed my convergence problem on a Zenith 60" rear projection. I replaced the IC's and removed the convergence board to do so. Those IC's have up to 18 connections for each one so you may have some loose connection points if we are talking about the same board. The IC's are connected to the largest heatsink for my TV, if you look from all angles, one view should get you a view of the 2-3 IC's present. Most people will tell you to completely remove the convergence board and check all the big resistors on board as well. Fuses are always a good option too. If you can solder well I would unsolder and resolder the IC's at the very least, but it is only a suggestion on my part. I am not a TV technician but an ATM/Computer tech. The boards look like only a sign from God will get them out but can be relatively easy. Let me know...
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Is the image bow-tie shaped, with red, green or blue fringing effects? If so, one of your convergence amplifiers has gone bad. (Bow-tie: at least one of the three primary colors in the picture goes out to the corners, but the top, bottom and sides are bowed in at the center.)
If it is simple color fringing, with no color grossly misplaced, something has messed up the convergence. This may be caused by a strong magnet near the set (for example, a poorly shielded audio speaker), moving the set so its orientation in the geomagnetic field is altered or its components mechanically shifted (rough handling).
If a convergence amplifier is bad, replace it before doing anything else. If you just have minor fringing, see your owner's manual for instructions on using the remote control to adjust convergence. If it isn't in the owner's manual, you'll need the service manual. Caution: if you try to adjust convergence with a failed convergence amplifier, not only will it not help, but you will have a lot of extra work trying to get it back to normal after you replace the amplifier. Try a small adjustment along one edge of the picture. If one or more of the selected color dots in the convergence pattern won't move, and you are sure you are following adjustment directions, stop immediately and proceed with hardware repair.
Convergence amplifiers are usually marked STK392-nnn where nnn is a specific variant number. Two are used; I usually change both because quite a few people have changed one and had the other die not long afterwards. Sometimes there is a fuse in the power feed to these modules that is also blown. If you change the fuse without replacing the amplifiers, you'll probably waste a new fuse.
Hi, The Mitsubishi TV set you have uses two of the STK 392-570 convergence correction IC's. These IC's can be purchased from here
These are the original Sanyo replacement type IC's. No aftermarket cheapo ones. Unfortunately this board that the IC's come on is part of the main Printed circuit boards. If one was available for a replacement, it would cost in the range of about 400 bucks. The way it sound that your TV set is intermittent, is that the IC's are not bad, but need to be simply re soldered. This happens a lot with this model number or set of convergence IC's. To tell you the truth, I have had to replace these types of convergence IC's very rarely. Mostly when the set come on with bad convergence and does not change. Find a friend or a neighbor who can solder, find the black STK392-570 IC's standing up against a large metal plate, turn over the printed circuit board and resolder all of the pins, just double check all of the solder points for solder bridges. Good Luck
The convergence Ics need replaced. In Hitachi, resistors and sometimes a coil needs replaced as well. The convergence/deflection PCB is available, but, the cost of that board is higher than having a servicer come to your home and repair the unit to component level.
If you are not familar with this circuit, then call a servicer. Have them replace both ICs not just one. Make sure they are repairing to component level and not replacing the board.
Hope this helps.
most like tes thats all your going to have to replace + the silicon as if you dont thet wil not last as long as they should. Also you may have blow fuseable resistors next to the ICs make sure you check them as well.
Sorry to tell ya Gemini, but there are no user serviceable parts inside a TV set unless your a technician as theres several safety issues of Hi Voltage involved as well as unsoldering and soldering. You Have a convergence problem or Pincussion issue with your set. No quick fix for this one. You need to call in a pro to assist you with this repair. Good Luck