Question about JVC AV-48WP74 48" Rear Projection HDTV-Ready Television

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Retrace lines and poor convergence

This set has been working great for ~3 years. I moved the TV into a wooden entertainment center (raising it about 8"). It was working great for about 2 weeks then last night it comes on with poor convergence and green-yellowish "bowing" retrace lines on the top of the screen. at the extreme edges of the picture I have double "colored" images (each gun). The center of the picture is pretty good... I thought maybe something came loose and gave it the open hand "slap" test and the "drooping" retrace lines dropped down further from the top of the picture.

 I disassembled and looked for loose parts/components near both tubes and at the lenses saw/felt nothing loose. Did not go any further in dis-assembly... I covered each lens and found the retrace lines go away when I cover the green lens. Any suggestions on what to look for next ? Is the service manual available to help troubleshoot ?

Jeff

Posted by jeffny on

  • jeffny Nov 03, 2007

    skippy101 and all.



    Took the (convergence) circuit board out. Found all solder joints very good. Took voltage measurments on IC804 pins 6, 7, 8 ,9 (since green was the problem) VCC was low (high) ~-18.2 V checked all resistors on CH1 Green Vert and all values within tolerence. IC804 running MUCH hotter than IC805.



    Removed IC804 805, ck VCC supply -29... found very little thermal compound on either IC, especially IC 804 that had 3 little "dobs" near the edge.



    Installed new STK392-110 and used liberal amounts of thermal compound and perform convergence and all is perfect.



    2hrs labor

    IC's $5.99 each

    Shipping $5.85



    having a perfect HD picture ...$$PRICELESS



    Jeff

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marco amezcua

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You have bad solder connections on the convergance board solder then and get back to me k

Posted on Nov 02, 2007

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1 Answer

Poor Picture


Hello,

It's a convergence issue. Go into the main TV menu under video settings and look for convergence. If it has an auto convergence select that and wait a minute the TV will adjust itself and give you a clear picture.
If the TV does not have an auto convergence and just regular convergence than select this. It will give you a grid pattern on your TV and you have to move the curser (using TV remote) and adjust each "point" so that each line is perfectly white. If you notice red or blue anywhere on that "line" then you have to adjust using the up, down, left and right arrow keys to "line up the red and blue lines with the nearest white line. It taked time and patience to do, but when completed, all lines on the grid pattern should be pure white and you will have a great looking picture.
You have to do this will all TV inputs (Video1, Video2 and so on) the reason Zoom looks good, is because you never used that screen as much and so the lenses didn't have a chance to get out of synch.
RPTV's are made of the three lenses (red, Blue and Green) and as you watch TV, these lenses slowly get out of alignment. So you should do a convergence about twice a year to make sure nothing is out of whack.
Hope this help....

Jun 26, 2010 | Sony Bravia KDL-32V4000 32 in. LCD TV

1 Answer

Bowed picture & red/blue/yellow separation


Your TV most likely has one of two possible problems.

Problem #1 - Failure in the convergence circuits. ( 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 are some photos of convergence problems.

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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.

0667c5f.pngSOLUTION

You will need to replace the convergence chips and possibly some convergence resistors and pico fuses. Its a fairly easy DIY job or you can call in a pro. If you want to do the repair yourself check the site www.TvRepairKits.com. Their kits include a photo instruction guide, original OEM Sanyo STK chips, convergence resistors, pico fuses, thermal paste, email/phone support, 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. Notice how dull the colors are and how white the screen looks. The screen may also look red, orange, dull, etc.

9e7eb5b.jpg

TV set after fluid change. Notice how bright the colors are now. Everthing looks crisp and sharp again.

182c282.jpg



2c07611.pngSolution #2


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

May 19, 2009 | Televison & Video

1 Answer

Red Convergence


http://electronicshelponline.blogspot.com/
http://schematicscom.blogspot.com/
http://homenol.blogspot.com/
Visit these sites. Convergence procedure of projection televisions are given in detail.

Mar 28, 2017 | Televison & Video

1 Answer

Switches off after 3 to 4 secs--little bright screen hor line and small retrace lines


On the my sony website, they said try unplugging the set for 3 or 6 minutes. Then plug it directly to the wall. If that don't work, and it won't; seek a service center. I have the same problem.

Next time we better buy Panasonic. Sony products fail ALOT. I had a 5 disc DVD Changer and it was defective and it was part of a class action lawsuit,

I believe this is the same sort of problem.

The sony Vaio laptop computer gets consistent poor reviews.

I brought an alarm clock and its back up battery never worked right out of the box.

I brought a cordless phone and the LCD display went blank.

I am so DONE with Sony.

Good name; Bad products.

Aug 23, 2008 | Sony KV-24FV12 24" TV

3 Answers

Red convergence wont move


if the red line is blurry and you have adjusted the screen focus control and does not work then you prob have a bad red CRT or bad red CRT fluid.........

convergence STK have nothing to do with the red being blurry

Dec 09, 2007 | Mitsubishi WS-55809 55" Rear Projection...

1 Answer

Heavy red lines all over


red lines running from left to right across the screen? or parallel
to say a persons body? the first is retrace lines the second is convergence, the back has to come off the set regardless, a layperson can attempt to fix the retrace by turning down the "screen control", I would not advise you to try & replace the convergence circuit.

Nov 26, 2007 | Sony KP-43HT20 43" Rear Projection...

2 Answers

Kp57wv600


One of the convergence output IC's has stopped working and needs to be replaced. If the IC shorts out then it will draw too much current and possibly blow a fuse, and the set will shut down to protect itself. The IC should be replaced and the set realigned by someone with experience in convergence circuits.

Jun 20, 2007 | Sony KP-51WS500 51" Rear Projection...

2 Answers

Green arcs from bottom up with darkest one at bottom on dark screens


there is a way to get rid of the lines, you need to enter a code from your remote to access a hidden menu. From there you can adjust the lasers in the tv(green lines)I beleive it is very sensitive though, if done wrong can reck the tv. Not sure of the code or directions on how to exactly adjust the lasers, actually looking for them my self. Hope i was some help though!

Jan 22, 2007 | Sony KP-51HW40 51" Rear Projection...

1 Answer

Convergence


You need to most likely replace the convergence output IC's probably STK392-110's and check associated resistors around it. HD is not mandated for 2009, only digital braodcast it is at that point all analog television broadcast must stop.

Jan 21, 2007 | Hitachi 46UX50B 46" Rear Projection...

2 Answers

Red Horizontal Lines


they gona get worse to dead circuit, a small capacitor (problably in the neck board) is bothering you, get a tech now that he can see the problem, gonna be cheaper now....good luck ps some times the picture say to the tech was going on

Aug 05, 2006 | Sony KP-51HW40 51" Rear Projection...

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