need help for my lenovo e570 screen backligtht

[TrezCoronas]

Hi, i need help for my lenovo e570 screen backligtht.

[TrezCoronas]

Hi! so my E570 screen backligth went off a couple months ago and now i wanted to repair it. While i was looking for the problem, i saw that there is a fuse missing (see red arrow in attached photo) on the display circuit board. Moreover, the fuse F1 (blue arrow) is cooked since I tested it with the multimeter and it is not beeping. I bought the used laptop a few years ago and there is marks that some repairs were made on him. Then, when I wanted to check the voltage, i discovered that i have a battery problem (i pressume). How do i know that? when i plug the charger to the laptop, there is an irregular rapid blinking looking like this: .....blink.....blink..blink.....blink.....blink..blink etc So now i have a second problem. I'm reaching to you to guide me on this adventure on raising my Lazarus from the death. Please note that i have almost all the tools (hot air rework station, microscope, desoldering station, small tools).

1.What should i do first? buy a new battery? test the voltage without the battery?
2. Proceed with changing both fuses or just F1? The F1 fuse (blue) is a 32V and 1.5A ? Specs for the fuse missing (red)?
3. Any thoughts would help
4. Or should let him go?

[mon2]

The missing fuse is not missing. There is no solder on the copper pads so these 2 points were masked off with the solder paste stencil. That is, part is missing here by design.

Yes, the fuse should be replaced since it is blown. Check Digikey / Arrow / Mouser. DK is $8 for shipping in Canada.

Before going shopping, review where the voltage from the power supply travels or does not travel. Start with the DCin power jack and confirm this ~19v makes it to the main power rail.

Which logic board is the one you have? Is it NM-A831 = E570?

Would you have a charger IC (BQ series) @ PU101?

[TrezCoronas]

I looked into the motherboard and one pin from a cable was not attached to the motherboard (see pic) i tried to solder it but not good (first try), also im waiting for the flux to arrive.
Q&A:
1.Which logic board: NM-A831 indeed!
2. Charger IC (BQ series) @ PU101: yes it is BQ series

Do i need an oscillosscope to test where the voltage travels? or there is another way before i solder the power cable to the motherboard?

[LazNo01]

I looked into the motherboard and one pin from a cable was not attached to the motherboard (see pic) i tried to solder it but not good (first try), also im waiting for the flux to arrive.
Q&A:
1.Which logic board: NM-A831 indeed!
2. Charger IC (BQ series) @ PU101: yes it is BQ series

Do i need an oscillosscope to test where the voltage travels? or there is another way before i solder the power cable to the motherboard?

That pad is ripped, there no copper there to solder on.. You need to scratch what left from that trace and run a jumper.

[mcplslg123]

The ripped pad is for DC jack and can be esily soldered with the clearly visible trace.
The blown fuse is located on the screen itself? Right? If so, probability is high that you have other shorted components on the screen power card. Most likely the backlit IC itself.