On startup using remote my Sony KD-30xs955 would
Hello
Seven blinkd of standby light in Sony TVs denotes a High Voltage Shutdown. Sony TVs have a special circuit built into, called Self Fault Daiagosis. This stage will detect the faulty stage and will give its symptoms in the form of blinks, and are codes to understand the fauty stage inside.
Here in your TV, its Extra High Tension [EHT] voltage at the final anode of the picture tube exeeds its maximum, that is it goes beyond 30KV (30,000VDC], and it is dangerous, that such high voltage will cause X ray radiation from the tube, and the above ciruit sense this condition and gives you a code of seven blinks.
To rectify this fault, you must begin with its main power regulation section. Plug out the TV from AC mains, and open it. Locate the power regulating system. It is easy, that the mains wire goes directly to that section. Which will have a fuse and large filter capacitor, retifier stalk, and an STK Ic screwed onto a heatsink. The STK Ic is the power regulator. It will heat up to more than 70 degree centegrade, and this heat will spread to its surroundings. There are some small capacitors, electrolytic types, are there, has a chance to reduce its actual value due to this heat, and value reduced capacitors will make problems to the actual regulation. you just replace all that capacitors first, keep an eye on its polarity, ie electrolytic capacitors have positve and negative terminals. There will have 5 or so of them, which will not cost too much, and easy to get from any electronic spare part shop.
Check all the soldering points in the power regulator section for any loose or bad solderings. It is best to resolder all the suspected soldering points by applying a little more solder, that loose solderings are very difficult to detect. Resolder all the pins of the above said STK Ic.
Then find out the secondary voltage stage, secondary side of the SMPS transmormer, a small transformer fitted to this section. For 30" TVs, the secondary main voltage will come around 125VDC to 130VDC. There is no adjustment controls for adjusting this voltage, as STK Ics are very accurate in regulation. If it seems to be more than the voltage said above, STK ic may be defective, and should be replaced with an identical type and number.
Before checking the secondary DC voltage said above, just disconnect the supply rail which goes to LOT said above, otherwise the set will shutdown, and there will be no chance to measure this voltage.
Just keep in mind that the power regulator system of your TV has the trouble. You just do these first, and if any more assistance needed, contact me through Fixya. Ok.
11/27/2010 11:01:51 PM •
Sony FD...
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261 views • 1 helpful votes
