Liquid Damaged Lenovo Laptop Repair

by solara70 in Circuits > Computers

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Liquid Damaged Lenovo Laptop Repair

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Symptoms:
This Lenovo V145-15AST had suffered liquid damage.

On powerup. the fan runs and hardisk whirs, sounding like its booting up. However, there is no picture on the screen.

This was confirmed by plugging in the hdmi output to an external screen. So all looks well, apart from no laptop screen output.

Lets try n fix it!

Supplies

Soldering iron.
Wire
Toothbrush
Lighter fluid.

Rear Panel Off

Undo screws from rear panel.
Crack open the lid using a spludger tool or your fingernails.
Disconnect and remove the battery.

Give It a Scrub

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Quite a few visible water stains.
Scrub clean using a toothbrush and lighter fluid.
Let it dry.
Screen connector looks good On the motherboatd.

Crack Open the Bezel

Prise apart the flimsy screen bezel from the edge using a spludger.
Undo the four screws holding the screen and inspect the edp connector.

Oh Crap !

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Found it.
Nasty short circuit at the male and female edp connector, caused by water damage.

Both connectors have melted away.
Crap!

Hack a Fix

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Ok so what now?

If im swapping out both damaged parts:
Screen £80
Edp cable. Hard to get hold off. From spain £50.
Ok, even at £130, still another problem. The edp cable is enclosed by a glued hinge cover panel cant seem to snap it open.. Hence why its a cheap Lenovo and why EDP cables are hard to find.

Dont really want an unsightly cracked open hinge panel affecting the closing mechanism.
Donor laptops are over £100 with a broken screen!

The hack I sm using, I first spotted on youtube "electronics repair school". So credit to Sorin..

Lets rip opn the male connector shroud, and probe the voltage on the two wires. Both show 19v, indicating they supply power to screen.
These tie up with pins 26 to 29 which can be used to power the lcd.

Lets solder the two broken wires together and bypass the male female connectors and solder the supply direct onto the lcd board. A proper hack. See my scribbles.

The male connector pins 23-30 were cut off clean and had no feed wires. The remaining connector will still be used to connect the board to ribbon.

The female connector pins 26-29 had also shorted internally to the metal ground shroud. These had to be pulled out like teeth (using fine tweezers and 45x jewellers magnifying glass), as they would have caused another short. Check resistance to ground for the supply pins, ensuring no low resistance readings.

The lcd female pads were too fine for me to solder without a microscope. So i traced them to a more convenient solder pad on the other side of the pcb.

Male and female edp connectors reconnected
Power supply wires soldered and insulated with heat shrink and bypassed direct to lcd.


Let There Be Light

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Press the power button and we have a working display.

Cheap hack for a cheap laptop.
Zero cost and environment friendly!
An Ideal fix during the covid chip shortage.

Job done.