Re: Need help finding LED backlight fuse [PICS]
I got mine fixed 2 weeks ago and now being busy with another laptop. The problem was with the connector on the motherboard. It had short right below the plastic which I suspect due to heat that has melted. It is really a big and messy job to de-solder this connector so better prepare for a spare connector which what I did.
memalt01
Member
Last Activity: 05-26-2014, 07:14 PM
Joined: 02-18-2014
Location: Dundee
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Re: Need help finding LED backlight fuse [PICS]
This is the LED socket on the motherboard again. pins 39, 38, 37 and 36 are ground but they should't be ground according to specs and the schematics. and pin 40 is NC. If I don't know better I would say the problem with the connector but nothing internally or externally damaged within this socket. Pin 36 is going to the ground (you can see me removing some of the paint from the copper on pin 36) but 37, 38 and 39 going no where eventhoug they are grounded somehow!...Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
I checked the LCD connector on the motherboard for backlight voltages and according to motherboard and the lcd schematics some of the readings that I am getting are wrong. pin 40, 39, and 38 should be a backlight Vbl = 6V~24V but 39, 38, 37 and 36 are grounded and pin 40 is not connected (nc) and that is totatly wrong according to schematics. Pin 1 is NC and 2, 3 and 4 are 3.3V which are right. I checked this voltages while connected to the lcd and while it is not connected to the lcd. It could be problem with inductor FBM2125 HM330-T...Last edited by memalt01; 02-20-2014, 08:01 PM.Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
Thanks sorinac, this is excelent motherboard schematic and matches the LED side of the connector voltages on the LCD specs. I will check it closely tonight and measure all the voltages in each pin on the motherboard LCD socket. When I closely look at the schematic, it seems like all these LED backlight power is coming from the GPU chip and there is no fuse in between. However, if there was a slight problem with the GPU then I wouldn't get picture on external monitor. I will check the capacitor's and the resistors tonight with this...Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
Yes budm, that would be a good way of finding the voltage levels on 40 pin motherboard connector. I have the specs for this LCD pannel
I will check it out the voltage levels but it is going to be extremely hard when I can't find the schematic or components id's for this motherboard. I was looking for open fuse or open 0 ohm resistor to fix this issue but everything seems to be ok but still no good display on the screen. I have a pic of the connector for this lcd pannel....Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
Hi budm, yes one of the leg is connected to the ground and the other leg measured 19V when the power was on last time. Is it good or is it bad? :-) I suspect you will go against shortening the component as the ground and the 19V may give some strong spark. That's why I was confused and didn't go head to short this but would you see any other reason for this dim display? What is that component in the picture (resistor or a diode?)Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
Tanks for the reply wishmark and dj, The components on this asus x54H has no labels, completely blank. Amost all the similar components as the suspected one have very small voltage variations on their both legs. And when I measured the resistance all the components have ohm value but this one is open circuit and side of the point has over 19V while the other point has 0V. This is not a fuse or a 0 value resitor as the other fuses has P or pl symbol on it and the jumpers has 0 in the middle. It is not a inductor as there is no coil...Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
I called asus regarding on backlight issue on K54L Rev 3.0 motherboard. Apparantly this is not a common issue which I suspected as the problem caused by not taken the battery out when changing the black spots LCD panel. Asus would not assist the self repairs so, I am on my own with this. I wonder if I short the component in above picture where one leg has 19V and other 0V? Would the motherboard fry?Leave a comment:
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Re: Need help finding LED backlight fuse [PICS]
I am having the same issue with no backlight on my asus K54L_HDMI Rev 3.0 motherboard. So far I changed the LCD cable and the 40pin LED screen with no joy. I checked all the fuses and 0 ohm resistors which all were good. A little component looks like a diode has over 19V on one hand and no voltage on the other. I assume the diode should behave that way but other components looks the same has very little voltage variations on both joints. Can anybody please advice me what to look for in this board? I will try to add some pics now....Leave a comment:
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Re: New Members - please post your introductions here
Hi guys, I am posting from Northern Ireland. Just posting to say hello and be able to see some of the docs.Leave a comment:
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