May 25, 2020
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My dell e7240 is not working(no dell logo,not able to access bios), on clicking power button, the wireless button,storage button stays steady and charging indicator keeps on blinking, on checking dell e7240 manual led diagnostics it shows that The memory modules are detected but encountered an error. I tried inserting new ram,swapping existing ram and resetting cmos battery but no luck.
I have recently modified some bios settings,removed winodws and currently there is no os present

Please guide me
 
Solution
some white deposit near by cmos,but cmos appears to be dry
mositure under the keyboard
green deposit just below palmrest,its just below the keyboard,can keyboard leak?

also currently i saw the green depoist only inside the connector for keyboard,mouse only(single connector) ..... can i pull this connector out. is this green deposit reason for laptop not starting, will this green deposit inside the connector cause any shortings?.....

The green stuff on it's own just sits there, what caused that to happen is what is very likely causing the system to not work. There is corrosion in the system from something leaking or being spilled on the system. You can clean off the deposits and corrosion but the damage...
May 25, 2020
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Remove your laptop battery and CMOS battery... leave it like that for 10-15 minutes.... (when you previously reset CMOS battery how did you do it?)
I removed the laptop battery, cmos battery then pressed on the power button for 20 seconds(without external power cable)
Ok i shall do it now, previously i have not kept both removed for more than 5 minutes.
 
May 25, 2020
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Also i noticed that at the end of track pads ribbon cable there is some black color(burned) at the point of connection to the mother board. Some strips in the end have misalignment caused while pulling it out @Vyrvelata
 

Maybe the whole connector have to be changed... as far as i can see (the runways seems burned)...If in a laptop repair shop if they can find you another connector, maybe they can solder it also...I don't recommend this but, you can try and find another ribbon cable connect it and see if it's starts, the problem is that once the connector was burned once, if you start loading it again, it might catch fire next time.
 
May 25, 2020
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@Vyrvelata , i got a usb keyboard,mouse so i am planning to keep the ribbon unconnected. can this burned connector be reason for lap not turning on? also i see moisture at partiular place below the keyboard(just below this the comos is present)
thanks
 
May 25, 2020
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@Vyrvelata its same,lap didn't start, showing same led diagnosis The memory modules are detected but encountered an error.

now i have kept cmos,battery,wlan card removed for more than 20 minutes before checking. Also i have not connected the keyboard,mouse cable to motherboard
thanks
 
yes,i disabled secure boot and some other options in bios and tried installing hackintosh and in this process i think lap got heated

You have physical damage to the system, green corrosion would not just be caused by heat, happens when there is a chemical reaction like when there is liquid or some other containment in the area. You said a few times something was wet in the system, that should not be happening, could be a leaking capacitor or battery or something was spilled in the system at some point that caused the corrosion.
 
May 25, 2020
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You have physical damage to the system, green corrosion would not just be caused by heat, happens when there is a chemical reaction like when there is liquid or some other containment in the area. You said a few times something was wet in the system, that should not be happening, could be a leaking capacitor or battery or something was spilled in the system at some point that caused the corrosion.
some white deposit near by cmos,but cmos appears to be dry
mositure under the keyboard
green deposit just below palmrest,its just below the keyboard,can keyboard leak?

also currently i saw the green depoist only inside the connector for keyboard,mouse only(single connector) ..... can i pull this connector out. is this green deposit reason for laptop not starting, will this green deposit inside the connector cause any shortings?.....
 
get new toothbrush softest tip you can find. its very important that brush is soft otherwise it can cause damage. then get isoprophyl alcohol 90%. Then disconnect power cable, main battery, cmos battery connector.

Gently use the toothrbrush dipped into isoprophyl alcohol and clean all affected areas, look the mainboard very carefully, under tapes etc too. Keyboard side only i dont think it leaked other side (might be possible too)

Open gently the affected connectors like keyboard and trackpad and clean inside the pins, do not attach any bad looking connectors , replace the cables, also check if you can clean cable if its not burned

toothbrush is good cause you can slide under connectors and some chips (obviously not larger bga chips) to clean corrossion between the chip legs.
 
some white deposit near by cmos,but cmos appears to be dry
mositure under the keyboard
green deposit just below palmrest,its just below the keyboard,can keyboard leak?

also currently i saw the green depoist only inside the connector for keyboard,mouse only(single connector) ..... can i pull this connector out. is this green deposit reason for laptop not starting, will this green deposit inside the connector cause any shortings?.....

The green stuff on it's own just sits there, what caused that to happen is what is very likely causing the system to not work. There is corrosion in the system from something leaking or being spilled on the system. You can clean off the deposits and corrosion but the damage that caused that won't be fixed. It's like having your house set on fire and you scrubbing off the tar and soot to make it clean again. It will be clean, but the fire still did the damage to it.
 
Solution
The green stuff on it's own just sits there, what caused that to happen is what is very likely causing the system to not work. There is corrosion in the system from something leaking or being spilled on the system. You can clean off the deposits and corrosion but the damage that caused that won't be fixed. It's like having your house set on fire and you scrubbing off the tar and soot to make it clean again. It will be clean, but the fire still did the damage to it.

On this case your probably right it but i have fixed countless laptops with liquid damage just by cleaning the connectors, more than half of the time motherboard is beyond repair, usually there is more than one component which needs to be replaced. I just give up if i see problem leads to super i/o or there is ripped pads and traces.

There is about 20% which work just after cleaning the liquid / corrossion off the board, usually this means you cant use some parts like internal keyboard etc but its duable. He should atleast try.
 
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Hang-the-9 is right about this probably do not work after cleaning but worth a try if you dont have money to replace motherboard or get new laptop.

Obviously do not use any liquid damaged part which could do further damage (example that burned ribbon cable), You neeed to carefully check every part of the motherboard, i would even check the other side under heatsink and connectors for liquid.
 
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