I've replaced the STK392-110s but Red Vertical convergence is still bowed
I have a convergence problem. The Red colour is several inches up from where it should be, and it is bowed such that it is more severe in the lower center of the screen. I replaced both STK392-110 convergence voltage regulators but... no change. I'd appreciate any suggestions. Someone suggested changing the feeder resistors - anyone got the specs on these?
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Need more details about how the screen is appearing warped.
if you have color separation and distorted image (warped,bowed, etc), then your Convergence ICs have failed. It is very common on rear projections. The solution is to replace the STK chips, check fuses and the resistors next to the STK chips. Replace as necessary and re-align via the service menu. It is about a $300 repair at a tv service center. You will need the service manual if you decide to do this yourself.
Try This: When you notice the symptons Use this simple test to verify. Go to the users menu on the tv. Look for the converge option probably under setup or video setting. Converge is short for convergence to align the red and blue colors to the green color.
If you cannot move the red either horizontal or vertical, then the STK chip has failed for red section. If you cannot move the blue either horizontal or vertical, then the STK chip has failed for the blue section.
If you can move both in each direction then the problem is something else.
Note if one STK chip fails, you replace both regardless. Note: The STK chips are black about 3 inches long and will be mounted against a large aluminum heat sink (metal fins). They have about 20 pins on them. I believe they are STK392-560s in that set.
The problem you're having is due to the failure of the convergence amplifier circuit. In that circuit are some components which amplify or control the signals to the dynamic convergence yokes, which line up the red green and blue images to superimpose them over each other to create a proper colour picture. When you get a failure in that circuit, it no longer aligns the images properly, and generally you get what appears to be badly set geometry in multiple colours. In some cases you will also get a problem with the part of the power supply that supplies the convergence amplifiers, or the digicon, which is the digital convergence control module.
This is a convergence problem that can be either poor solder connections at the convergence ICs or defective ICs. If you can solder and feel comfortable working inside the set where there are potentially dangerous high voltages, update this and further details and instructions will be provided.
You will need to replace both convergence ICs they are STK392-110 and you will also need four 6.8 ohm 1watt resistor. You can get replacement ICs and resistors at the following link with free installation instructions. http://servicemanuals.vstore.ca/
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