Lenovo Y50-70 (not touch) - Screen LED Backlight

[Kashi1712]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

Ok guys, good news, it is working ! Lcd cables had a bad contact on the screen so light is back now ! The ohm resistor was faulty :-)

Thanks again !

[rookieme]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

glad to hear that!

[Csabeeboy]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

Guys, I don't know how to start a new thread, but it's related to the same lcd backlit problem.
Symptom: black screen, otherwise laptop works fine, even external monitors are ok.
Reason: Laptop hinge cover is broken, and when closing the lid, the lid pressed against the bottom part of the screen.
Solution: I ordered a new screen, which only lit up in a very very dim way. Because it did show some dim picture, the back light must not be working.
I tried to ring the fuse next to the 30 pin, and bingo it wasn't working.
I asked for the help of my younger brother who had a soldering station, and he jumped the fuse.
It works!

[wcars05]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

So I seem to be in the same boat with a different type of leak... I stumbled upon this thread a while back and I get voltage the whole way to the panel as per: http://diyprojector.info/forum/index...KbmJcxo4TbKDBV

I get ~ 20V on the 4 pins when testing between the GND and Backlight supply voltage. (there are 2 sets of 4 pins that make up the VS and GND going into the panel.

Looks like something died in the screen?

I was curious if there is a way to test for signal for enable/disable and the pwm?

I do have access to a oscilloscope. Looking for some diagnostic guidance before I waste $90 ordering a screen.

Page 21 shows the full diagram of the connector.

pins 28-31 are Back light GND

Pin 32 is enable
Pin 33 is pwm dimming

pin 36-39 are Backlight supply voltage

I figured the odds would be slim that all 10 arrays of back light LED's would go bad at once, but I might be wrong?

Any help is appreciated,
Thanks!

[Distopik]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

Hi i have a similar issue and im looking for assistance i swapped the zero ohm resistor and get 20v on one end and 19.7 on the other end with the power supply when the machine is turned off but when i turn it on it drops to 02.9v on both sides of the im assuming it might be the wrong type of zero ohm resistor but im no expert so any help is appreciated

[IceLv]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

R375 should be the component circled in red in the following picture. Maybe yours is blown too.

(Source: http://www.elektroda.pl/rtvforum/topic3228153.html )

I know this is VERY OLD post, but just wanned to say thanks a lot! Just replaced screen cable too and lost backlit, this picture saved me! That resistor/fuse was blown and i solered those 2 pins directly and everything works! Thanks!

[alekshernandez]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

I've spent over 2 years looking for this fuse. I've been using this laptop with my 50' LCD screen.
I will go ahead and replace that fuse in the picture to see If I'm lucky.
This system had a fall of about 8 feet. All body cracked and replaced all parts. (screen was working normally, touch). After I assembled everything, screen wont come on. I can see the image with a flashing light.
Thanks everyone who collaborated in this post.

[Igorylo]

Re: Lenovo Y50-70 (not touch) - Screen LED Backlight

Distopik, I have the same issue. Have you fixed it?