Thanks everybody for this great forum!! I have a Proscan 55lc55s240v69 that did not power up when I first got. I have read all the posts on this tv and of course the first thing was to remove the back and visually inspect. The p.s. had 3 1000uf caps with the tops bulged pretty bad. They checked at 400-500 uf. I just replaced the 3 to check and see if it would power up and it did. I noticed a high pitch squeal noise at t-801 transformer when it was on. I went ahead and replaced all the electrolytic caps thinking it would take care of it. The tv powers on fine, but the noise is still there. I can feel a vibration when I put my finger on the infamous C857 cap. I did not replace this as it looked good and checked out capacitance. I don't have an ESR meter. I know this high pitch noise is usually from a leaking cap or a diode. The only diode I see that's attached to that c857 cap is on the back of the board vd804. I did test all diodes on the front and removed one leg to check. With the c857 removed, I diode checked the vd804 and showed .537 volts one way and .213 volts when leads reversed. I didn't want to remove to check cause of the size. So I guess my question is what would cause this noise and any way to verify or is it replace one part at a time to see what corrects this. Oh, by the way, The c857 cap is the 22nf 2kv style. Any help would be appreciated. I know some noise is normal, but this is a high pitch squeal noise. you cant hear it from the front, but the back is loud and fear it will take out something else. I hope I did the pictures right.
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