Laptop only turns on when screen cable is disconnected

Question

I recently bought a hot air station and have been practicing how to use it on all the old broken devices I can find.

This laptop (an hp 425) had this problem that it wouldn't turn on, no image on screen or external monitor and when trying to turn it on, both the power button led and the led next to the power jack would blink infinitely.

When disassembling it to check the motherboard, I noticed that if I tried to turn it on with the screen cable disconnected, the leds would act normally (power button led would stay on), so I connected an external monitor, but still no image.

So I used the hot air station to heat up the gpu chip, tried again with the external monitor, and now I get image. But when connecting the laptop screen cable and try to turn it on, both leds start blinking again and it doesn't give image on any screen.

I couldn't find what these leds blinking mean for this laptop. Is it the cable or could it be a problem in the motherboard?

Answer 1

http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c01732674

Continuous blink

AC power adapter LED

Power adapter

Insufficient power

But most likely not "Insufficient power" but really "shorting out" If the LCD's power cables to the inverter are shorting out, the power management won't let the device turn on.

I can't say for certain without the laptop in front of me but LCD inverters are a very common point of failure. So are any cables that go through hinged joints.