Sylvania LD320SS8 - Power Cycling

[Giacomo Siffredi]

Hey Guys,

I have a second-hand Sylvania LD320SS8 circa November 2007 which has been in my service for about two years. Recently it has developed a power cycling problem in which the TV can operate normally for either two minutes or two hours. Then suddenly, the screen distorts into vertical green lines and there is an audible screech which lasts about two seconds. After which, the set cycles off and restarts. Once it turns back on, it functions normally until it does this again.

I have removed the back and examined the boards. I am attaching some pics as well. It appears to me that at least one of the 4700uF 35v Radial Electrolytic Capacitors on the PSB is slightly bulging.

Please advise what steps I should take to more appropriately diagnose and perhaps repair this issue. Thank you.

[dick_barton]

Re: Sylvania LD320SS8 - Power Cycling

It looks as though the diodes on the board have been running extremely hot. Have you checked them out. Also the heat may have dried the component solder joints in the area highlighted. A picture of the back of the power supply could prove useful.

[Giacomo Siffredi]

Re: Sylvania LD320SS8 - Power Cycling

Hey Dick Barton,

It looks as though the diodes on the board have been running extremely hot. Have you checked them out. Also the heat may have dried the component solder joints in the area highlighted. A picture of the back of the power supply could prove useful.

Upon examining the board, there appears to be widespread burn throughout. The requested pictures are attached herewith. I should note that over the two years I have been using this TV, there has been an apparent burn in the panel in the upper-left portion of the screen and extending toward the middle. Since it only dimmed and did not distort the image in the affected areas, I pretty much disregarded it. Any chance there is a correlation between the burn on the board and the burn in the screen?

[dick_barton]

Re: Sylvania LD320SS8 - Power Cycling

Although the pictures do show the extent of the heating on the board they are not sharp enough to make any judgment.
However as a first attempt I would be tempted to go over every solder joint with fresh solder in the areas which are discoloured.

[dick_barton]

Re: Sylvania LD320SS8 - Power Cycling

Any chance there is a correlation between the burn on the board and the burn in the screen?

What burn in the screen?

[CapLeaker]

Re: Sylvania LD320SS8 - Power Cycling

I would definitely clean up that power supply. Lots of dry joints and probably needs some new caps as well. However, don't rule out the main board jet. Fix what you know is bad, then retest it.