Horizontal line on screen problem - Videokarma.org TV - Video

Satcom123 · #1 05-09-2011, 06:35 AM

Hello I hope this is the place for this tech question. I have a 36" or so Sanyo tv. Model number DS31520. It's about a 10 year old tv. It started to develop a problem when watching it. Picture would go to a solid horizontal line across the center of the screen. We would tap the side of the set and it would come back for awhile then it would do it again. Opened her up and its got those one large single ckt cards with just a picture tube in it. There is a large standing L shaped heat sink on the board that when gently flexed, the picture comes back to normal. All that's connected on it is a chip. So me figures its a cracked solder joint. I refloated the joints and when I powered it up, it poped and that was it. Now the horizontal line is still there but shifted to the right. My blundering soldering skills revealed I made a solder bridge where it shouldn't have been.

Now with all this said, do you think this chip is now bad?

And if so. With what I described has anyone else had this type of problem with the line across the screen and what did you do to fix it?

I know it's old and we probably just need to go out and buy a newer tv but before this it worked perfectly. If just replacing this chip restores it back it would be good. Anyone want to give me some guidance? I thank you.

Satcom123 · #2 05-09-2011, 08:05 AM

Well I did some research and got a download of the service manual. The chip in question is IC501 which is the vertical deflection device. It is "LA7847" . So if I go out and get one of these I can CORRECTLY solder it in and go from there. Should I be looking for anything else that might give me a surprise when repairing this?

dieseljeep · #3 05-09-2011, 08:37 AM

The first two numbers in the model number designate the screen size. The 31" used an RCA CRT. Unless it's a very low hours set, the CRT probably looks rather tired.If you change the chip, change all the electrolytic caps in the vert circuit as well.

Satcom123 · #4 05-09-2011, 11:01 AM

Thank you for the info about the caps that should be changed. As far as the picture tube, it still has a very good display and bright. The chip was only 4 dollars so I ordered one. The caps shouldn't be too much.