Motherboard diagnostic beginner advice

[Mess]

To save you some time: the most important bits are in bold.

Some further examples/explanations or to the side & in grey - you can probs skip them if it's TLDR for you. Sorry, I've got ADHD & tend to over-explain stuff - just like I'm doing right now 😅 Briefness is for poets not me 🙈

Please help!! 🎶I'm just a girl in a world that wants to scam me out of lots of money for any tech stuff/repairs 🎵 Seriously tho, I'm poor&I can't afford to get laptop diagnosis, especially if it ends up needing a new motherboard. Where I live, all the tech shops are run by very dishonest guys, who always try to scam people, especially women, and are really rude if you ask any questions.

E.g. One guy told me laptop fan replacement was £150 cheapest I could find as it's very difficult (i ended up getting a replacement for £15&did it myself in ~15min). The other guy called me crazy for saying that plug chargers with more than 2 usb port exist.

So, I'd rather learn as much diagnosis as I can myself to avoid all this. :/ I already did some research and possibly narrowed it down to a few component issues, but I'm a bit stuck now and need some further guidance. I wrote down my questions at the bottom 🙏


BRIEF HARDWARE INFO: Laptop model: HP Spectre x360 13-ac00x
Motherboard #: DAX31MB1AA0 Rev A
Graphics: Intel® HD Graphics 620 (integrated)
Memory: 16GB LPDDR3-1866 SDRAM (soldered in)


ISSUE SUMMARY:
Moved my laptop and the screen suddenly turned white with flickering black squares&lines. I turned it off by pressing power button, but when I tried to turn it on again a bit later, it wouldn't boot anymore:

It turns on, but the screen remains black, fans start for a sec and then stop, and I get 5.3. light code: "the embedded controller cannot reach the BIOS within the established time limit."

(idk if relevant but the laptop had overheating issues as it's a HP (i.e. Heating Problems©, a.k.a. Hazardous Piece (of shit)™) laptop 🙄 and the screen would sometimes get flickering black stripes. Also, several issues have gotten worse after windows updates, I'd fix them with BIOS update or something like that, but lately it's been trying to update several times a week! So idk maybe another update could have done something to cause this)

WHAT HAVE I TRIED SO FAR:

• Tried all sorts of resets (AC, Battery, RTC battery removal, discharge, etc.),
• Windows Key +B, Windows Key +V,
• connect to TV w/HDMI,
• clean the dust inside the laptop with pressurd air
• Inspected the motherboard for any visible damage (there's none as far as I can see without a microscope)

The only difference was when I do Windows key+B+power button BIOS update, the fans don't start at all. The rest of it remains the same (black screen, caps lock light blinking 5.3code) even after I wait for more than 40sec.

QUESTIONS

• From what I could find online, this could either be an issue with BIOS chip, RAM, or GPU?
• If it's BIOS, would a BIOS flashback from a USB be possible on this motherboard without display?
• If it's memory issue, since RAM is soldered in (😭), I assume no repairs would be possible?
• Or given the initial screen issues, is it more likely that this is a GPU fault?
• Is there anything else that I could do to diagnose it further? I have a digital multimeter but I'm a beginner with all this so I'm not sure how/where I'd need to use it. I watched some motherboard repair videos and found schematics for this motherboard, but there are so many things in there, I've got no idea where to start. It took me like an hour to locate the bios chip, GPU, embedded controller, and a few other processors on it.

Thank you for taking your time to read this! 🙏 Appreciate any guidance on this ♥️

[mcplslg123]

Laptop diagnosis is not any easy task and need knowledge,skills and patience.

To begin with, measure voltage on all coils when powered on with no display. mention the coil number along with voltage.

As far as blinking code is concerned ,they are general in nature and dont provide the exact clue. Dont attach much importance on them.

Next measure resistance to GND on all coils(with no power attached(battery+adapter). To measure this, put black probe of your multimeter to Ground and red probe on target coils..
Meter should be set to 200 ohms scale when measuring coils near cpu/gpu. rest of the coil should be measured on a scale of 20K.

[Mess]

Laptop diagnosis is not any easy task and need knowledge,skills and patience.

Thank you so much for your reply!! Yes, but I'm willing to learn! It's quite interesting the more I look into it. The difficult thing is that there's so much info and a lot of it contradictory/misleading. It's hard to know where to start and what's correct.

To begin with, measure voltage on all coils when powered on with no display. mention the coil number along with voltage.

Aah you'll need to dumb it down further for me I'm afraid 😅
what multimeter settings should I use (I saw some videos where diode&continuity test setting was used for it, on my multimeter- these are separate separate)? Also, double checking, I'd need to use input on the right side, correct?

Sorry if next questions sound stupid, but there's so much contradicting information out there.. e.g. people calling transistors capacitors.. I don't want to mess it up further. So, coils = inductors, right? 😅 I'm not sure if I'm able to identify them all. There are not many markings on the motherboard and, as I said, the schematic is takes me hours to understand. Do you have any guidance on this please? I'm kind of relying on visuals of the motherboard right now. So for example, here are some parts that I've tried to identify:

I might have misidentified some 3-pin components as diodes here. As some sources said they are diodes, while other said they're mosfats.😕

I also not sure about all the small components that look like ceramic conductors only in black. I believe some of them could be inductors? And the larger components that I've marked as conductors, could also be inductors? 🙈

Also, can I do these tests without a battery? My laptop is able to run on AC only (without a battery in it). and I'd rather not damage the battery while doing this.

Next measure resistance to GND on all coils(with no power attached(battery+adapter). To measure this, put black probe of your multimeter to Ground and red probe on target coils..
Meter should be set to 200 ohms scale when measuring coils near cpu/gpu. rest of the coil should be measured on a scale of 20K.

Okay, again, which settings on my multimeter should i use for this? 😅I'm don't think I can set up measurement scale on my meter. It's supposed to have an autoranging feature where it select the optimal range automatically. Would this still be okay?

Again, thank you so very much again for taking your time to reply!! 🙏🤗