Lenovo V15-IIL 82C5 powering but no screen

[SFB]

I currently have a friends laptop that went blank while he was watching something. It powers up but no screen onboard or external.
If the battery is connected the power light is solid, but if I try with only the powersupply connected it flashes (might point to something?)

I have tried the most common troubleshooting to no avail, and there doesn't seem to be any obvious short anywhere on the board.
I can do more basic/common repairs like replacing components but if it needs anything like programming chips I do not have the equipment for that and I hope it isn't a bad GPU.

Any ideas would be very much appreciated

[mcplslg123]

Some lenovos power on indicator keeps flashing on adapter-thats usual and not an error indicator.
Whats the mb markings?

You need to take the mb out of casing and then measure voltage on all coils to begin with.

[SFB]

Some lenovos power on indicator keeps flashing on adapter-thats usual and not an error indicator.
Whats the mb markings?

You need to take the mb out of casing and then measure voltage on all coils to begin with.

That is definitely worth knowing, thanks.
The board is the GS44D/GS54D NM-C711 Rev:1.0. I found the schematics and Boardviewer file in another thread.

I did check the other day and there was a voltage on them all but other than the Main, 5V and 3.3V I wasn't sure what they were supposed to be so I will have a look at the files for them. I can get a cheap BIOS reader/programmer if that might bed something I need. It has got the onboard ram which is the first time I have seen it.

[SFB]

All voltages on the coils are correct, though I'm not sure what I am supposed to be getting in the +VCCIN - I am reading 1.62V

[mcplslg123]

Lenovo's has many cases with on board ram failures. There is no accurate guidance in schematic to disable it(Page10).

Which onboard ram you have?

I beleive pulling the board_ID 6/7/8/9 to 1111 postion is very likely to disable the onboard ram.

[SFB]

I ended up getting a programmer and found BIOS files on another thread, one of which disabled onboard RAM, and no luck with them. I'm not sure if it is worth messing around with moving resistors as well?
I'm considering reflowing the chipset as it is pointing to a graphics problem if not the RAM. The fan was very clogged up so working on the idea the heat may have cracked some solder or something as he was watching something when it went black.
As you can tell, I'm just guessing at this point.

I've added some files of the board incase anything jumps out.

[mcplslg123]

Dont reflow SOC as mb may go beyond repair.Onboard ram disable thru bios edit is not always a success.

Btw, do you have a dc supply? If yes tell us the consumption on it and the pattern it jumps high/low after switching on.

[SFB]

I'll not do that then haha
In regards to the RAM I'll leave trying to disable via the resistors for the moment.
I have a bench power supply so will test that tomorrow and report back.

2 things I did forget to mention before was on boot I am not getting CAPS lock nor NUM lock lights, but do seem to be getting a screen backlight (the screen goes black).
With not getting an external picture via HDMI though I'm guessing I can rule out a screen issue?

[mcplslg123]

Since you have the dc supply,just share the consumption pattern after pressing power button.

Does it jumps to 700mA or so and varies slightly and stuck there?

PS:Its not a screen issue

[SFB]

So I tried with it together but the battery had gone dead overnight so it was trying to charge and drawing 900mA while off.

With battery disconnected once started it jumps up to almost 1A for a second before almost instantly dropping and remaining at 380mA and the fan slowly ramps up to full.

When just the board being powered on its own it floats around 700-850mA with a couple spikes up to 948mA before dropping and staying at around 320mA. The only thing on the board getting hot is the chipset.

[SFB]

I did make a few videos to show the pattern, but they are too large to upload here.

[mcplslg123]

With the variation in consumption pattern from 948mA to 320mA,I beleive onboard ram should'nt be the issue.

[SFB]

Thanks for that, I've taken a day off looking at it as I've reached the end of my knowledge really so at a bit of a loss. I am obviously wondering if it is a silicone issue, but do want to check the gates as saw elsewhere they can cause problems.