What is the fault with a sansui sv2916 tv that has an east west pincushion?

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open the tv and then put it on then look carefully where the spack is, if it is from the line transformer then replace it with thesame number if u can but if u can not take it to a qualifield techni bcuse the voltage is very high

Hi, The Logik lk74pf flyback that you replaced. What did you replaced it with. I also have the same tv with the same problem. Also found a 1k resistor blown in the supply line from the flyback to the vertical deflection circuit.

menu ch+ 1947

The pincushion it intimately related to the horizontal circuits,the electron beam must travel farther to reach the corners of the crt and it does to the middle and so without pincushion circuits the raster would be bowed in on the sides on crts 27 inches are larger.Pincushion corrections straightens the raster by modulating the horizontal yoke current at a vertical rate.In an RCA tv the pincushion circuits are usually numbered 4800and the pin amp will probably be numbered 4801,its drive transistor should be Q4802,R4802 will be the width control,and R4805 the e/w pin amplitude. its inputs from the vertical should be Q4801 (subtractor) Q4803 (buffer) you should have a parabola waveform at 4801,yoke current can be modulated here without effecting high voltage.when Q4802 conducts voltage should decrease across Q4801 and the voltage drop across the yoke increases. The east west pin amp control 4805 controls how much of the vertical parabola is input to U4801 to compensate for changes in width caused by variations in beam current.By varying the e/w control resistor you can know if the circuit fault is in the input or output,if the picture varies in size the fault is in the input to U4801,if it does not vary check the output or U4801......hope that helps

hi there.im not familiar wih the model,but your fault lies in the east west correction circuit.excessive width usually means a short circuit e/w modulator diode,with the curved sides.normally,a narrow picture with curved sides points do dry jointed/open circuit polyester capacitor.if a firm slap has an effect,then its most likely a dry joint which makes for an easy life.the vast majority of east west correction circuits are based in tle line output stage,and generally not complex to fix.hope this helps,regads,steve.ps. look for s/c by 299 and by 228 diodes,check those..

probably a problem with the pincushion or the east west generator send it back to the repair guys and tell them what it is doing. Would be easily missed on some programs.