Zenith TV 1994 model SM2568S picture compressed
Hi fellow techs,
This 1994 25" Zenith TV model SM2568S has a complete picture which occupies about 40% of the CRT face plate.The picture is compressed and centered about the middle of the screen.(Wide black bar on top and wide black bar on the bottom) My coworker has a 1995 27" Zenith TV with the exact same problem. Sometimes I get the full picture with 2 fine horizontal lines in the middle. All the caps around the vertical IC are OK.(ESR OK)The vertical IC LA7838 has been resoldered.Is there something else I need to check before I grab the scope? Best regards, Jacques |
Jacques Carrier wrote:
Hi fellow techs, This 1994 25" Zenith TV model SM2568S has a complete picture which occupies about 40% of the CRT face plate.The picture is compressed and centered about the middle of the screen.(Wide black bar on top and wide black bar on the bottom) My coworker has a 1995 27" Zenith TV with the exact same problem. Sometimes I get the full picture with 2 fine horizontal lines in the middle. All the caps around the vertical IC are OK.(ESR OK)The vertical IC LA7838 has been resoldered.Is there something else I need to check before I grab the scope? Best regards, Jacques I believe I have the same set, and once encountered the same problem. Unfortunately I too changed the vertical IC before I discovered a poor solder joint on one of the caps for that chip. Look REAL close at your PWB to see if you don't have the same problem. |
Ken wrote in message ...
Jacques Carrier wrote: Hi fellow techs, This 1994 25" Zenith TV model SM2568S has a complete picture which occupies about 40% of the CRT face plate.The picture is compressed and centered about the middle of the screen.(Wide black bar on top and wide black bar on the bottom) My coworker has a 1995 27" Zenith TV with the exact same problem. Sometimes I get the full picture with 2 fine horizontal lines in the middle. All the caps around the vertical IC are OK.(ESR OK)The vertical IC LA7838 has been resoldered.Is there something else I need to check before I grab the scope? Best regards, Thanks a lot for the tip Ken. I resoldered all components around the vert. IC and the set is working fine! Jacques Jacques I believe I have the same set, and once encountered the same problem. Unfortunately I too changed the vertical IC before I discovered a poor solder joint on one of the caps for that chip. Look REAL close at your PWB to see if you don't have the same problem. |
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