I received a phone call from a client who wanted his television checked.
I requested him to bring it to my shop so that we can check it out.
Within thirty minutes he arrived at the shop, according to him the television was hit by power surge but when I opened it I did not see any sighs that it was power surge related issue.
I scanned the board top side and I did not get any suspect component.
I turned the board to the bottom side and noted numerous dry joints and one component burnt as you can below.I replaced the burnt capacitor and did the re-soldering of any joint I was not happy with.
I tested the H.O.T transistor and found it okay, the fuse was also found okay.
I applied the power and still no sign of life and therefore decided to take the diagnosis to the next level.
Next level means using ESR meter and testing all capacitors on suspects circuit like horizontal circuit since capacitors with high ESR can pull down the B+ to the level that the television will not power up.
I did some ESR tests starting with B+ filter capacitors and bumped on capacitor C561(47uF/160V) with ESR reading of more than 100 ohms.
Looking at the capacitor below it looks very innocent but the effect it has on the circuit is devastating.
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Thank you guys
See you in the next class