Question About TCon Board Failures

[JohnCT]

Most TCON boards fail with two general symptoms: either no picture or a very bad picture. Occasionally we'll see one with vertical strips either over the picture or instead of a picture.

On older models, the AS15x chips were common. I used to order them 50 at a shot out of China. But like VCR repairs, they dried up almost overnight. I just put an AS15 chip in an older Sony for another dealer, but that's the first one I changed in over a year.

Newer Samsungs (5-7 years) have DC-DC converter ICs that fail. Like the AS15, they are surface mounted and have to removed with hot air because they have a bottom metal pan that serves as ground and the heatsink.

Multi layer chip caps are common failure items, and they generally short hard over. These are small brown bricks (look like tiny Snickers bars) and are usually installed with two to six in parallel. With the ribbons to the display disconnected, check for voltage on any inductor you find on the board. Generally speaking, every inductor should have a voltage on it. If a voltage is on an inductor with the display disconnected but disappears when the ribbons are reconnected, you have a shorted chip cap or COF chip in the display. If you find no voltage on an inductor with the ribbons disconnected, check for shorted multi layer chip caps.

John