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A real comman problem with that set is vertical IC will blow, burn a hold in the board itself, Part Number is a LA7838 Vertical IC, located right center mounted on a heat sink, and will about seven legs on the IC,, on defection board.Remove back and see if that IC is in pieces?
This is an easy repair if you've ever soldered and would not be too costly for a repair shop to do it for you. The problem is a bad Vertical Output IC (usually mounted on an aluminum heat sink with the part on it labeled LA78?? ) and 1 or 2 bad capacitors. Some times you can even fix the problem by re-soldering the contacts of the IC- To find the IC follow the 4 wires that come from the Yoke (which is a contained coil of wires slipped over the neck of the picture tube(s)) back to the board. 2 of the wires go to the horizontal o/p and 2 to the Vertical o/p the thinner gauge wires are for the vertical. Be sure to vote/rate me if this helped Thanks! In this case the vetical o/p IC is LA7838 and the IC is located at the right front corner of the PCB (main)the 2 capacitors are- 100uf 35V and 220uf 25V.
There is a problem with the vertical circuit. Many times it is the vertical IC. This is a small flat IC attached to a heat sink. It may be merked LA7838 or something similar. You ca try resoldering the pins as a bad connection can also cause this. If that fails, replace the IC.
Keep us posted,.
Dan
That sounds like vertical failure. Does the blue line run across the screen from side to side? Try resoldering the vertical output IC and see if that straightens it out. This is sometimes been a problem with that chassis. Let me know how you make out or if you need additional help.
Good Day; Sounds you have a bad vertical output IC that is defective along with some caps. Change IC > LA7838 > IC401 and ALL CAPS like cap off of pin #6 1ufd 25v and etc.
Good Luck, big IRISH.
I've heard this is could be a cold solder joint and am looking for advice on which IC to re-solder.
1 whatever you have heard is correct
as whenever you smacked the lelt side it works fine.
2 you will have to check loose contact in vertical section. your vertical ic might be located at the left side of the tv.
3 check any connector is loose near vertival section.
4 any preset is loose in vertical section.
it is a simple problem if you are not technical person please get it done by tech person.
as your tv is old & if it is done by tech person tell him to replace all elrctrolytic capacitors in vertical section.
good luck.
If you have a picture but the top is folded over, your vertical IC is probably good and you need to replace the pump-up capacitor next to the IC. When the pump-up cap (typically a 47 or 100uF 35V cap) is open then the picture will have white lines and foldover at the top. The typical vertical output IC is the LA7838, but I am not familiar with exactly which output IC your set uses.
vertical ic LA7838 diagram
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