I need a schematic or good advice. I tried replacing some of the caps. c541 a 100uf and c578 a 47uf . i dont know what part of the curcuit these belong too, but they didnt look bad and they didnt fix the problem.I tried to use a heat gun on the curcuit. i guess the next step is to replace ic 551 the la78045. has anyone seen this before so i am not buying unneeded parts?
sylvania model srt2027 vertical foldover
Nov 05, 2009
4 Replies
Foldover isn't the IC - there's one or more caps you missed.
Mark Z.
mark Z
i replaced all caps in the 500 series curcuit what i see on the top of the screen is "retrace lines" maybe about 2or
3 inches but the picture is ok so i think foldover might be the wrong term
What you are describing is caused by the "boost capacitor" usually 100uF at
35 volts and located physically near the vertical output IC.You can go to bdent.com, register if necessary and get a PDF of your vertical IC. Using that, you can tell which pin the boost cap is associated with.
This is important - when the boost cap is bad the vertical IC will usually run HOT and may fail soon if the situation is not corrected.
Mark Z.
.
at
ed
ythanks i replaced the "boost cap" origanal was a 47uf but it didnt fix it so i tried a 100uf and wualla it fixed it. the bdent.com couldnt display the data sheet but i found it on
formatting link
thank for your help
Sam M
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required