Question about Toshiba 42H81 42" Rear Projection Television

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Replacing chips on convergence board

I've researched solution for blue out of convergence, and the first fix seems to be replacing the chips. I need to remove the chassis to gain access to the bottom of the main board to unsolder the chips. Here is the question: There are big red wires that look like they carry a lot of voltage. They go from the chassis up to the tubes. I remember from years ago working on typical TV's that there was a bucket load of residual high voltage. I need to disconnect these in order to remove the chassis. If the tv is unplugged, is there a shock hazard? I have a service manual for the model, but it doesn't address this .

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Re: replacing chips on convergence board - Toshiba 42H81 42" Rear Projection Television Projection Televisions


Posted on Sep 03, 2007

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The left side of the picture has red and green stripes and ghost images. The right side does not have this problem, but the picture is not quite right. The convergence chips were replaced two years ago and...

That sounds like the convergence problem I had about a year ago, and like you, I replaced the convergence chips and that fixed the problem. It's cheaper to replace the chips if you do it yourself, but maybe not if you send it out for repair. If you can find an exact replacement board, that would fix it too, but I wouldn't necessarily expect it to last longer. The advice I read on replacing the convergence chips in my rear projection TV was that they would last 2 or 3 years and then need replacing again. So you're within that range.

Feb 27, 2010 | Sony KP-51WS500 51" Rear Projection...

1 Answer

I have a Sony KP-61V60. I seem to have a problem with the color covergance where my screen looks almost 3D with the red sticking out. What do I need to do to repair this myself? How do I know if my RGB...

If you go into the customer menu and select CONVERGENCE and red or blue will not adjust in some direction you have a Convergence circuit problem.

Most of these sets use two STK-392-110 or STK-292-560 CONVERGENCE ic chips.

Both chips need to be replaced. If convergence will not adjust you do not have a bad "bulb" these sets use three picture tubes--red, green, and blue and the convergence circuit "converges the three pictures".

Usual parts cost total is under 30 dollars if you buy the parts on Ebay--there are places on the net that sell kits for 70 or more---they contain the pair of chips and other parts that may be needed--from my point of view they are a waste of money as most of these sets just need the two chips replaced--some will need a bad resistor around one of the chips located and replaced as well--on Ebay you can buy a pair of whatever chips the set uses for under 20 dollars including shipping.

Right now the site where I research these models for exact part numbers is down but I can help if you have some skill at soldering and want to fix it yourself. Most shops are going to get 300 or more for this type of repair.

Let me know if you have questions or need help.

If this information has helped you rate this solution as I do this here for free.


Nov 25, 2009 | Sony KP-61V90 61" Rear Projection...

1 Answer

My red,green and blue colors are off,needs to be convergenced

HI. there is a convergence circuit board that controls the rgb stream and it also is the principal manager of the colors. if you cannot collaborate the cross hairs or, even out the rgb, this will confirm convergence board failuer. the chip set on this board is faulty. Replacing the convergence board or stk chips will fix this issue.

Jun 05, 2009 | RCA Projection Televisions

1 Answer

Lots of Blue shadows off to side. concaved picture almost

HI, this is a failed convergence chip that is located on the convergence board. it will need to be replace ASAP. you can just replace the chip or , you can order a new board.

Replacing the chip can be a rough job if you don't have tech experience. if you are a fluid tech and you can solder and know your way around a circuit board, just replacing the chip will cost less. if you are not an experienced TV tech, i recommend a service call to the nearest TV tech to replace the convergence board.

May 20, 2009 | Sony KP-46WT510 46" Rear Projection HDTV

1 Answer

Blue spot on screen

Hi. this is called convergence failure. the convergence board is a circuit board that regulates the RGB(RED BLUE GREEN) streams that make up the color picture. If the convergence board chips are malfunctioning, you will see a distorted view of these RGB streams. This is what you are experiencing at this time.

Simply replacing the convergence board or chips will fix this issue.

Please rate and have a great day:)

May 17, 2009 | Projection Televisions

1 Answer


HI, normally when this occurs, this will signal a malfunctioning convergence chip that is located o the convergence board. this convergence board controls the calibration attempts when syncing the RGB streams.

Simply replacing the convergence board or chip will fix this issue.

May 15, 2009 | Hitachi Projection Televisions

1 Answer

Where to buy the convergence board of a 55PP9502

You can find a replacement auto convergence board for a model # 55PP9502 from this major Philips part distributor at the following link:

Philips 55PP9502 Replacement Part Auto Convergence Board

Feb 02, 2009 | Philips 55PP9502 55" Rear Projection...

4 Answers

Red CRT board not working. Blue seems to be going also.

Your TV most likely has one or more possible problems.

Problem #1: Convergence Chip Failure ( common problem )

Here are some of the most common symptoms and example photos of a convergence problem
  • 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.
Here is a quick test....

Using your original remote go-to the tv settings then goto the convergence section.

Try to adjust the red and then the blue convergence.

You should be able to move them up, down, left, and right.

If you can't move them in all directions your convergence chips are bad and should be replaced. This is a common problem.

2c07611.pngSolution #1

You need to replace the convergence chips and convergence resistors. Check the site They have put together a kits for most models. If you don't see a kit for your set send them a quick note and they will put one together for you. Their kits include a photo instruction guide, original OEM Sanyo STK chips, convergence resistors, pico fuses, etc.

Problem #2 CRT Fluid is Cloudy

Projection TV tubes have a liquid coolant that is used to keep them from overheating. After many years the coolant in the blue and green tubes will become cloudy and cause the screen to look dull, red/orange, etc. You may even see halos around images.

Picture of a set that needs the fluid changed.

TV set after fluid change


2c07611.pngSolution #2

What you will need to do is replace the coolant and clean the crt. You can get a repair kit from that includes replacement coolant, photos. instructions, etc.

Jan 30, 2009 | Philips 55PW9363 55" Rear Projection...

1 Answer

Samsung hcm4216 rear projection

· Samsung parts for convergance problem

Aug 24, 2007 | Samsung HCN4226W 42" Rear Projection...

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