Entertainment Center: TVs, Stereos, VCRs and DVDs - Soney Big Screen/ Convergence

I HAVE A SONEY MODEL KP-61V15 REAR PROJECTION TV. I TURNED ON THE TV THIS MORNING AND NOTED A BLUE SHADOW, ON TEXT AND PICTURE. I CHECKED THE CONVERGENCE AND NOTICED THAT THE BLUE VERTICAL LINE WAS NOT STRAIGHT UP AND DOWN. IT WAS ON A TILT. I TRIED TO ALIGN THE BLUE WITH NO SUCCESS. I REMOVED THE REAR COVER ON THE SET. CLEANED THE LENS, MIRROR, BLEW OFF SOME LIGHT DUST ON THE BOARDS. I TRIED TO ADJUST THE BLUE LENS BY LOOSINING THE WING NUT, AND TWISTING THE LENS, BOTH CLOCKWISE, THEN THE COUNTER CLOCKWISE POSITION. NOTING THE CONVERGENCE OF THE BLUE VERTICAL LINE AS I MADE ADJUSTMENTS. I HAD NO CHANGE IN THE CONVERGENCE. ALL I COULD DO WAS CHANGE THE FOCUS. I DID NOTE WHEN THE SET IS OFF FOR A FEW MINUTES. AND FIRST POWERED BACK UP I CAN ADJUST THE CONVERGENCE ON THE BLUE, AND THE VERTICAL LINE IS STRAIGHT UP AND DOWN. WITH NO TILT IN THE LINE. THIS ONLY LASTS OF A FEW MINUTES. THEN IT GOES BACK TO THE SAME PROBLEM. THE SET HAS NEVER BEEN MOVED OR SUBJECTED TO ANY VIBRATIONS OR SUDDEN BLOWS, IT HAS SURGE PROTECTION, ON THE POWER AND VIDEO CABLES. THE TV WAS BUILT IN DECEMBER OF 1994. THIS IS THE FIRST PROBLEM I HAVE EVER HAD WITH THIS SET. HOPE SOMEONE CAN HELP...
DAVID S MAYER

Good Morning, DavidSMayer:

The repair archieves are full of Sony convergence problems and seem to be linked to a poor design on the convergence board, itself. For instance, this one from a 56" Sony is similar:

The convergence verticle line is fine, but the horizontal line extends red off the righthand side and blue off the left hand when the verticle line and center are set correctly. Nasty pin cushion on all four edges (center of each pulled in) and the rgb images are badly misaligned further out from the vertical center line of the TV. Corners are badly misaligned for colors, but not pulled in as badly as the center of the edges. I assume something went bad, but nothing obvious. Is is possible that it simply needs some kind of physical allignment of theguns? I had thought not since the center convergence is good, but I know not much about projection TV's.
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Remove speaker grill to get to convergence board. There are two fuses on this board. Usually one of them is open. If one is open, you have a bad output IC. No way to tell which one. I would replace both of them and both fuses. I think they are IC1704 and IC1705, and fuses are F901 and F902. Do not touch any of the controls or anything on the picture tubes to try to repair this problem or you will make things worse.
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IC1704 and IC1705 are no where to be found on the circuit board. However, there are two chips labeled IC904 and IC905 which are physically near F901 and F902. Can anyone verify if IC904 and IC905 are the chips actually referred to?
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Have exact same set. IC1704, 1705 are on right hand side of board. They are big and should say STK4278L on them. I had/have same problem. Replaced the IC's + simple voltmeter check of + and - 18V supply and check for blown associated caps. No obvious problems. Now same thing has occurred 3 months later. Replacing IC's has again fixed problems but it seems obvious something else is going on. -18volt supply to IC's reads -18.8 when related fuse is pulled and -18.4 when installed. +18volt reads 18.2 (fuse out) and 17.9(fuse in). This (-18v supply) could be the real problem but not sure yet. You can get new STK's from AudioLab in Georgia or B&D enterprises. They are both on the internet.
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If you need a service manual on the set, this site is usually able to provide one, has secure ordering, etc. If they don't have your set listed, they are good about finding one, anyway:

http://www.treasurechestcorp.com/Default.htm

Smokey ;)

Originally posted by Smokey
Good Morning, DavidSMayer:

The repair archieves are full of Sony convergence problems and seem to be linked to a poor design on the convergence board, itself. For instance, this one from a 56" Sony is similar:

The convergence verticle line is fine, but the horizontal line extends red off the righthand side and blue off the left hand when the verticle line and center are set correctly. Nasty pin cushion on all four edges (center of each pulled in) and the rgb images are badly misaligned further out from the vertical center line of the TV. Corners are badly misaligned for colors, but not pulled in as badly as the center of the edges. I assume something went bad, but nothing obvious. Is is possible that it simply needs some kind of physical allignment of theguns? I had thought not since the center convergence is good, but I know not much about projection TV's.
**************************************************
Remove speaker grill to get to convergence board. There are two fuses on this board. Usually one of them is open. If one is open, you have a bad output IC. No way to tell which one. I would replace both of them and both fuses. I think they are IC1704 and IC1705, and fuses are F901 and F902. Do not touch any of the controls or anything on the picture tubes to try to repair this problem or you will make things worse.
****************************************************
IC1704 and IC1705 are no where to be found on the circuit board. However, there are two chips labeled IC904 and IC905 which are physically near F901 and F902. Can anyone verify if IC904 and IC905 are the chips actually referred to?
****************************************************
Have exact same set. IC1704, 1705 are on right hand side of board. They are big and should say STK4278L on them. I had/have same problem. Replaced the IC's + simple voltmeter check of + and - 18V supply and check for blown associated caps. No obvious problems. Now same thing has occurred 3 months later. Replacing IC's has again fixed problems but it seems obvious something else is going on. -18volt supply to IC's reads -18.8 when related fuse is pulled and -18.4 when installed. +18volt reads 18.2 (fuse out) and 17.9(fuse in). This (-18v supply) could be the real problem but not sure yet. You can get new STK's from AudioLab in Georgia or B&D enterprises. They are both on the internet.
****************************************************

If you need a service manual on the set, this site is usually able to provide one, has secure ordering, etc. If they don't have your set listed, they are good about finding one, anyway:

http://www.treasurechestcorp.com/Default.htm

Smokey ;) :)

THANK YOU SMOKEY!!!!!
I CHECK THE FUSES, WHICH WERE GOOD. AND WHILE I HAD THE BOARD OUT I NOTED THE SOLDER CONNECTIONS ON BOTH THE CHIPS WERE IN VERY POOR CONDITION. I HIT ALL THE PINS WITH A SOLDER GUN AND SOME NEW SOLDER. AND BINGO... PROBLEM SOLVED. I GUESS THE HEAT CREATED INSIDE THE CABNET EVENTUALLY DEGRADED THE SOLDER JOINTS, AND CAUSED THE PINS TO LOOSE ITS CONNECTIONS. ALL I KNOW IT IS WORKING FINE NOW. THANKS AGAIN...... DAVE MAYER :) :) :D

Good job! Scratch one up for the guys in the white hats!


Smokey :)