I have replaced the convergence and vertical output ICs in this set because it was powering off. The set now works fine and looks pretty good with the exception of having 1 each of a red green and blue horizontal line in the topmost portion of the screen. I'm guessing that there is something in the vertical output circuits causing this, but am pretty clueless as to where to look now. Note that all the electrolytic caps associated with the vertical output IC were also replaced.
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the 43h71 has a pair of convergence ics that commonly go bad and cause this problem. replace original stk392-110 with stk392-120. the upgrades have a collector rated at 4 amps vs the 110's 3 amps and should be more reliable.
also know that they hyperboard in this set can cause squiggly lines throughout but will not affect the convergence.
You may be suggesting a convergence problem..when the blue and red boxes will not center. You have bad grounds on the convergence ICs. Resolder or replace theses ICs. Or you may be asking about a problem in the vertical section. Vertical problems will appear as horizontal lines on the TV. In this case you have bad capacitors near ithe vertical IC and must also resolder or replace the vertical IC.
It seems the solder is broken in Vertical Convergence Amplifiers or it is damage internally. This model has 2 Conv. Amps: 1 for Horizontal (Red, Green and Blue) and 1 for Vertical Convergence output (Red, Green and Blue), if the convergence does curve at the top and bottom, it is because Vertical Converegence output is no good. The Conv. Amp. costs around 20 dlls. Thats why you can not fix it with the Menu option. Good luck!
If the convergence is off more than 1/2 inch or so you can't adjust. you have a failure of hardware. most likely the output IC. This set has 2 outputs for convergence. Each output contains 3 circuits, Six circuits altogether 2 red ,2 blue and 2 green. The normal customer adjustment will only alow adjustment of blue and red. They should be converged onto the green. There is a much more complex adjustment in the service mode for Geometry and convergence. These adjustments are only needed when you replace a failed componnent like the output ic. These ICs have been upgraded several times since the production of this set. The latest and most powerfull version is STK394-160. If feel up to it I suggest changing both outputs and the corresponding output resistors. Then do a complete geometry and convergence alignment.
you need to replace both convergence ICs they are STK392-110 you can get replacements at the following link with free installation instructions so you can do the repair yourself. http://servicemanuals.vstore.ca/
The STKs are three channel ICs they each control horizontal and vertical of one color the third channel controls part of green and the other half of green is controled by the other ICs third channel. Its customary for the Ics to fail and only have one channel bad in the IC. However its recomended to change both because of the bad Ic having green it can actually weaken the other IC and that one will fail shortly.
the green is half controlled by half of each of the convergence Ics meaning green horizontal is controled along with the red and green vertcal is controlled along with the blue Ics. So if you have replaced both Convergencs ICs the problem is most likely a resistor that is in the green circuit. You will need a schematic to locate which resistors are in the green vertical and horizontal convergence circuit
chances are that IC804 has failed. You have two ICs that allow you to
converge the three colors. IC804 is used for Red Horizontal and
Vertical Convergence and also for Green Vertical Convergence. IC805 is
used for Blue Horizontal and Vertical Convergence and also for Green
Horizontal Convergence. These ICs run very hot and have a very high
failure rate which sometimes will cause damage to resistors in their
associated circuits. They are both STK-110 and it's best to replace
them both at the same time. It's also a good idea to upgrade them to
either STK-150 or STK-180. These will run a lot cooler than the
Before replacement do
inspect for any open or overheated resistors as I stated earlier. Being
you only have problems with Red Convergence the plus and minus power
supplies should be okay since they are common to both ICs.
www.tritronicsinc.com. They have the Hitachi CZ00433 (STK392-150) in
stock for $20.11 ($32.43 retail). These are Hitachi OEMs. I've had very
good results replacing STK392-110s with these chips. Do check for open
or overheated resistors before replacing these chips