I have a hitachi 57" rear projection tv. I was watching it one day and all of a sudden there was a bow in the screen in the blue color. Initially this would only happen after the tv was on for a while but it got to the point now when the bow is always there. It is only the blue and I have visually checked all resistors on the board around the IC and can see no signs of a blown anything. Any ideas what may be wrong?

This set should use two of the STK-392-150 CHIPS for convergence, see attached photos.

If this is the case both chips need to be replaced and some adjustments made; if in your case blue will not move in some direction or you have a blue bow in the picture, one of the two chips mentioned is bad.

SD TECH

unplug your TV look on the back for a three controls marked red / blue / green "screen" turn / tap on them; watch the screen when you find the "dirty" control clean it with "TV tuner cleaner spray"

Projection sets have two very common problems.

The first common problem is convergence

These sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the picture to look normal. This is called convergence.

When its out of alignment the video will look 3-D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired. Convergence problems are very common on all Projection TV sets including Sony, Samsung,JVC,Philip Magnavox,Panasonic,Akai,Pioneer, Hitachi,Mitsubishi,Zenith and others.
You can get more information and a DIY convergenece repair kit with instructions from the link below.

Here are some of the most common problems with these sets...

*Screen Looks 3-D
*Colors wont align
*Screen may look distorted or warped or bowed
*No Audio/Video - TV Shuts down - May also make a constant chirping sound

Problem #2 - Another common problem is dull or washed out video.

Your set may have one or more of the following symptoms....

*Dull looking picture
*White looking picture
*Halos around objects
*Red/Orange looking picture

You can see some more examples and find a fix using this link on Fixya http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

Ur convergence it dead.U know how to solders?Tries these websites for convergence kit.Tv repair World.com,Tvrepairkits.com.

This is a very common failure on Projection sets. Its called a convergence problem.

You may have one or more of the following symptoms.

• Screen looks 3D
• Colors don't line up
• One or more colors can't be adjusted when using the convergence menu.
• Screen is bowed or warped.
• No Audio / No Video - Makes Chirping Sounds

You can see some examples and find a fix here...


http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

The tv must be old, get new 1

Unfortunately it sounds like your CRT's ( picture tubes ) are getting weak. You have 3- red, green and blue. It would not be in your best interest to repair it because of the cost of the crt's and if we can still buy them. A lot of analog parts such as those are very hard to locate and is getting worse by the day.

This is a problem with the convergence circuit. If you can solder, try resoldering the pins on the convergence ICs. If that fails to resolve the problem, replace the ICs. These ICs are large and black, attached to a heat sink and are marked STKxxx.

Keep us posted on your progress.

Dan

The problem is with the convergence circuit. If you can solder, try resoldering the pins on the convrgence ICs. If that fails to resolve the problem, replace the ICs. These ICs will be large and black, attached to a heatsink and be marked STKxxx.

Update this with your progress.

Dan

I got a question.

Do you have any stereo speakers anywhere near your television?

This sounds like something a magnetic field could cause from speakers being too close to the tv.

If so try to relocate them and see if the problem goes away.