Blown IC Caused Dim Display In LCD Mag 700p
An LCD screen was brought to my shop by a young man. While the man waited, I powered up the LCD screen and the standby LED came on but the display was too dim to see. From Experience, either the fuse on the inverter board is blown therefore no power to the back lights or the actual board has problems. Let us find out.
A lot of useful information you can get from the back sticker on the back of the LCD screen.
Only three screws have to come off in order to go to the inside of the screen. Once these screws were off, the inside was revealed.
My main focus was the main fuse but as I was heading that way, I looked around and I saw something that was not normal. Can you see the blown part in the photo?
Well, if you have not spotted the blown IC from the previous photo, here, it is clear and marked with a red arrow. To my surprise, the fuse was not blown. That part number is 4511GM. It was not easy to get the part number but I was lucky to have the same exact board in my junk pile. Below is the link to the datasheet:
I pre heated the board and then went directly to take the old IC off to be replaced. I was not expecting this to happen but it did. Check out the next photo.
I guess I used extra heat with my re work station or the bottom area of that IC was already damaged. Either way, it has to be fixed.
I put the IC back to the board and I connected a wire to it. I usually use a transformer wire that is already isolated and I scratch both end of that wire to make conductive.
My apologies to you all out there for not posting this photo because I totally forgot to take picture of the finishing product.
Once I put everything back together and powered up the LCD screen; it worked for almost two hours before I called the customer to come and pick it up.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.
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Note: You may check out previous post about fixing active speaker in the below link: