How does one test an IC to see if shorted?

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rodc
How does one test an IC to see if shorted?

I am having an issue with some haloing and offsert colors on my Sony kp53V85 and noticed the led flashing 7 times before turning on. I was all hyped to rip out the IC's and change them (along with the picos) based on reading teh articles here. However I did a diagnostic test with the onscreen display and the TV indicated no errors.

How can I ensure its a faulty IC before open board surgery? Any help appreciated. Thanks!

jsf2323
If you are having what is

If you are having what is refered to as a convergence problem then the IC's would be your problem . When the red green and blue colors are out of alignment these IC's regulate there patterns . Along with the pico fuses also check the resistors surrounding the IC's to ensure the are not opened as well . Mainly if the pico fuses are good suspect a couple of resistors may have opened . They look discolored or burn't or are just opened . Replace both IC's not just one of them as they both use the same + & - voltages together. The easiest way to test a shorted IC is to find its primary voltage inputs and check if they are shorted to ground when still in the circuit . James

Bernie52
(The easiest way to test a

(The easiest way to test a shorted IC is to find its primary voltage inputs and check if they are shorted to ground when still in the circuit . James)
Exactly how do you check? Should the tv be plugged into the AC outlet but not powered on? I know where ground is on my board, just not sure what still in the circuit means. BTW excellent forum!

jsf2323
With the TV unplugged . Look

With the TV unplugged . Look for the pico fuses that protect these IC's . They are green or yellow in color and are labeled PS and with four numbers on the board. If these are opened your going to have to replace both IC's . Some units have four of these pico fuses protecting the IC's as others only use two . Also these fuses could be good and the IC's have devolped open circuit in the IC. If the IC is opened it is tricky to check. With the problem you have described the IC's are most likely bad. When i described in the circuit i mean't by not taking the IC off the board. Also connect a ohm meter with the negative (-) to a ground connection and use the postive (+) to test every pin on the IC . Some of the pins of the IC goes to ground but many others do not . So if the that don't go to ground but that pin measures shorted to ground you have short on that line . Now to test whether it is the IC or the circuit feeding it unsolder that pin from the board , If the pin still reads shorted to ground the IC is your fault . If the IC now does not read shorted to ground put your (+) to circuit only with the pin not touching and see if it reads shorted to groung , if it does yoy have a short in that line , but this is rare. My money is you have a bad IC. Make sure your fuses are good and no resistors are opened . Hope i did not confuse too much . Now if you don't want to pay much and you can pull the board out yourself and remember how it goes back in take just the board to a service shop and ask them how much they would charge to install the IC's and the fuses and or the resistors . If i was doing this the parts and labor would be around $90.00 to $110.00 . Just make sure you mark your wires . It is very important you mark the red - green - blue wires as there are two sets of each color. Now if you take the whole TV to the shop it might cost you $200.00 to $300.00 . Big difference. Total parts if you do it yourself $25 to $35. Good luck on the repair , James

sunkanmi
How can I know ,when an ic is

How can I know ,when an ic is faulty. Apart 4rm being burnt.

 

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