Tip & How-To about Televison & Video
Why convergence problems happen and what to do.
Many rear projection TV sets made from the mid 1990’s through 2006 develop convergence problems and the reason is simple: Most use 2 IC chips (there are a few that used 3 and a few Mitsubishi use just one) and the chips are on average about 2 1/2 inches wide and 1 1/2 inches tall.
Most have 18 pins or more and are black in color---Most will have a STK NUMBER printed in white on the front of them. The most popular one ever used is STK-392-110, IT was used in Panasonic, Hitachi, JVC, and even some Mitsubishi sets.
The chips have a metal back on them and are attached to a large metal plate usually with fins, it is called a heat sink. A white material like a grease is placed on the metal back of each chip before it is bolted to the metal. The Heat sink compound (or grease) is designed to transfer heat quickly from the part which gets quite hot to the metal heat sink to keep the chip cool.
After some years (usually 5-8) the grease has dried out from the heat it moves and the chip overheats and goes. Depending on what happens it can also take a resistor or two out around the chip when this happens or fuses designed to protect the voltage going to the chip can be blown.
About 70% of the time just the chips need to be located and replaced and the set adjusted with the original remote control.
Some sets are fairly easy to repair with this problem and a few very difficult (RCA’s made from 2003-2206 or Pioneer sets fall into this group).
This can be a do it yourself repair but first you want to determine if it is your problem. All these sets have in the customer menu a way to attempt to manually correct convergence--go there first and see if it will adjust.
If Red or Blue will not move in some direction(left/right or up down) You have a convergence problem.
A lot of sets have an automatic way Hitachi calls it “magic focus” and it only attempts to adjust at less than 20 points on the screen.
If the set does adjust, whatever the brand, you will need to with the remote get into the tech menu for your set, adjust and SAVE the adjustments.
I have repaired over 1,000 of these sets with Convergence problems and when it comes to parts you have a lot of options.
1. You can go online and buy a “kit” for your model----I do not recommend this as it is expensive and usually contains parts you are never going to need.
2. You can ID the chips and buy them locally----I do not suggest this either as it will be as expensive as buying a useless kit.
3. Typical suppliers here sell the chips for about 25 dollars each(X 2) but most of the parts are available online or on EBAY for much less. One good source is Suburban Electronics in Maryland--chips that will cost you 50 for a pair they sell for less than 14 for a pair and they have almost every part needed for this repair.
4. Both chips have to be replaced, I have seen shops that just replace one and it is a ticking bomb. Suburban is also on Ebay-----select advanced search, search by seller and type sewsales55.
The also have a online catalog, this is not a advertisement for them; I have bought a lot of parts for my own use from them----
5.) Remember the old heat sink grease must be removed and new applied when you install the parts.
6.) Taking set to shop may not be a economical option, most get 250-350 for this repair versus under 30 dollars parts cost if you can do it yourself.
I have answered a lot of questions on FIXYA for this kind of problem, check my record out. If you like what you see and need my help---post a question: “Attention, SD TECH” and if I see it I will assist you with your set.
Some Mitsubishi and Toshiba and other sets will actually be dead when this problem happens but there are usually simple ways to know if this is the case.
Regards, SD TECH
Typical convergence problem
Sony with a convergence problem
Posted by SD Tech on
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