40volts to the back lights then slowly loses it

Michael Quarterman  that is a big depends. It is possible that this is strictly a capacitor issue. It is also possible that this is a failure of some other component that causes a capacitor to fail etc. First thing you need to do is to tell us the exact make and model of your TV. After that you do want to post some good pictures of your boards with your question. That way we can see what you see and make further recommendations.在已经存在的问题里加入图片

Right now it is most likely that this is an isolated power board issue. Toshiba is another one of those Silent Running Black Helicopter companies that is absolutely paranoid about providing any information to any DIY’er, so schematics etc. may be difficult to obtain