820-3115 no image after lcd connector

[jamiehorn1]

Hi all,

I have a 820-3115 that I have replaced the lcd connector on and now I get no image but I have backlight.

I tried another connector but same symptoms, any ideas?

Thanks

 

[jamiehorn1]

also backlight out is 27v so it can see the screen and powers the backlight, I also get 3.3v.

so it's just the creation of the image that’s not working, any clues?

 

[jamiehorn1]

FYI it chimes and has backlight - just no image?

 

[dukefawks]

Problem with LVDS lines. Check all LVDS lines at the connector on diode mode. L9080 is a common one to be damaged. I assume you have tried a known good LCD assembly.

 

[jamiehorn1]

Thanks Duke - will get to it tomorrow.

 

[jamiehorn1]

And yes KG display same issue. The display was actually working prior to my work on the onewire and ISL so unless I killed it the cable and LCD should be fine

 

[jamiehorn1]

Hey Duke - L9080 has completely disappeared and with perfect pads! Weird lol. But yeah replaced and working.
many thanks as normal ??

 

[jamiehorn1]

ah just when i thought it was all good - USB ports seem to cause machine to power off. i've replaced U4600 and D4610 which had some small liquid damage. still no luck - any ideas?

 

[jamiehorn1]

And it does it with the thunderbolt port too, I don’t think they had anything in common?

 

[dukefawks]

Does it turn on when something is already plugged in to USB? Voltages on U4600?

 

[jamiehorn1]

Yes it powers and chimes then cuts out within 5 seconds and reboots. Just loops.
on U4600 I get 5 volts in and out. I replaced both filters but no luck.
not sure if it’s related but if I put the SSD in the machine via flex cable, it boots half way and turns off

 

[jamiehorn1]

I'm thinking if the ports are receiving 5 volts (because the drive lights up and measures okay) then it dies and reboots - could it be U4650 which decides if USB data goes to the SMC that is dead?

 

[dukefawks]

It seems like the 5V cannot sustain the load. I would look more into the 5V circuit and see if voltages are dropping. I bet this was the original fault with this board before the messed up LCD connector.

Check for low resistance too on 5V_s3 and S0 rails.

 

[jamiehorn1]

Thanks Duke, I’ll give it a go and leave it at that.