Hey all,
I have fixed two LCD TV's, a computer monitor and motherboard thanks to this website and everyone that supports and contributes to it. I am now fixing a LCD TV, Samsung LN32B460, and haven't found any threads on it. The symptom is no power. The power led[RED] does come on, it blinks 5 times then goes out. It will however stay lit if you press it again but no picture, no sound, no back light. I opened up the back and examined the power supply. No Bulging caps, burn marks, or bad solder joints, visually looks okay. I tested both fuses and they're good. I tested the output to main/logic board thanks to a voltage pinnout printed on the board, and everything checks out.
I turned off the lights to see if there was ANY backlight activity at all, there was none. I also performed the flashlight test, there seems to be no image at all. I would like to test the inverters, but am not exactly sure how to do this.
Since no light OR image, and powerboard seeming to be in pretty good shape my head turns to the main/logic board. Everything visually looks okay, except for the underside which is covered it what looks like spilt coke~a~cola.(which i doubt because every surrounding areas is completely clean including topside of board.) The other thing I noticed about the main/logic board is that when it is hooked up completely and tv is in "on" position(LED on) the heatsink on he processor gets VERY HOT to the touch. I wish I had an infrared thermometer to find an exact temp., but i couldn't hold my finger on the sink for more than two seconds without instinctively pulling away.
Anyway, am I right to suspect the main/logic board in this case? And if so what are some ways to go about testing it? (I am ready to replace it if needed)
-Are there any further tests that you suggest I make on the power supply?
Thank you
Update: I have replaced 5 caps on the upper right side of the board with no change in activity. The caps were
25V 1200uf
10V 1200uf -- All caps by Sam Young
3X 50V 474uf
I will replace the rest of the caps, just need to take a trip to the electronics store.
I have fixed two LCD TV's, a computer monitor and motherboard thanks to this website and everyone that supports and contributes to it. I am now fixing a LCD TV, Samsung LN32B460, and haven't found any threads on it. The symptom is no power. The power led[RED] does come on, it blinks 5 times then goes out. It will however stay lit if you press it again but no picture, no sound, no back light. I opened up the back and examined the power supply. No Bulging caps, burn marks, or bad solder joints, visually looks okay. I tested both fuses and they're good. I tested the output to main/logic board thanks to a voltage pinnout printed on the board, and everything checks out.
I turned off the lights to see if there was ANY backlight activity at all, there was none. I also performed the flashlight test, there seems to be no image at all. I would like to test the inverters, but am not exactly sure how to do this.
Since no light OR image, and powerboard seeming to be in pretty good shape my head turns to the main/logic board. Everything visually looks okay, except for the underside which is covered it what looks like spilt coke~a~cola.(which i doubt because every surrounding areas is completely clean including topside of board.) The other thing I noticed about the main/logic board is that when it is hooked up completely and tv is in "on" position(LED on) the heatsink on he processor gets VERY HOT to the touch. I wish I had an infrared thermometer to find an exact temp., but i couldn't hold my finger on the sink for more than two seconds without instinctively pulling away.
Anyway, am I right to suspect the main/logic board in this case? And if so what are some ways to go about testing it? (I am ready to replace it if needed)
-Are there any further tests that you suggest I make on the power supply?
Thank you
Update: I have replaced 5 caps on the upper right side of the board with no change in activity. The caps were
25V 1200uf
10V 1200uf -- All caps by Sam Young
3X 50V 474uf
I will replace the rest of the caps, just need to take a trip to the electronics store.
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