This Sharp TV literally eats vertical deflection ics. I investigated with an oscilloscope and found that pin 22 of the main ic, X2933ce, has no output drive waveform going into the vertical deflection chip. There is not even a dc voltage on this pin which appears to be open. Unfortunately, this ic is prohibitively expensive. I tried to cross reference it with another similar looking ic on another board, X2701ce, but neither ic is listed in the NTE catalog.Has anyone had a similar problem, and is there an inexpensive solution that I may have overlooked?
If the main IC is not putting out a vertical drive signal then the vertical output will not do anything and therefore will not be damaged. What exactly do you mean by the set "literally eats deflection IC's"? What is the number on the vertical output IC? I will bet that your pump-up cap or pump-up diode is defective.
Pin 1 is ground and 2 is output. If pin 1 is actually grounded then there must be a coupling cap in series with the yoke, and this would prevent the IC from shorting if the input to the IC is such that the output rails to B+. In this case, no matter what the input is, the output is protected and the IC will not be damaged. With the IC unsoldered and removed, measure for a short from the pad of pin 2 to ground. If that line is shorted then the output will destroy itself the second the set is turned on. I cannot think of any other case where the output would be immediately destroyed. If the pump-up diode was open then you would have no output, and if the pump-up cap was open then the IC would work for a while (with heavy white lines at the top of the picture) and then short out. I do not have any information on the X2933ce, other than the fact that the whole part number is RHIX2933CEZZ (I think).
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Good to you, sis, i have a problem with my sharp tv. tv cuts off 10 seconds after switch on and destroying vertical output ic and i chang the ta8403k an the line is there still?
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The vertical o/p is a TA8427k, and what I mean by eating the ic is the part becomes shorted between pins 1 and 2 as soon as power is applied after replacement. The pump up diode D501 and capacitor C508 were checked, along with the vertical deflection coils, and the large electrolytic capacitor in the yoke return. The 1 ohm current sensing resistor in the vertical NF network was also ok.
Is it possible that without vertical drive and with the input of the ic going to ground through the 4.7k resistor on pin 22 of the X2933ce the bias conditions on the vertical output ic cause an excessive current to flow through the lower half of the totem pole output stage, destroying this transistor?
Is there any cross reference or technical data for the X2933ce and other recent Sharp ics? Thank you in advance for any assistance rendered.
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