First, I had to remove the can overtop of this area on the PCB. (I used a preheater, hot air, and a knife blade, but if anyone has any tips for this process, they would be appreciated, because it wasn't easy to get off).

While doing so, I accidentally knocked half a dozen or so components from their intended positions by poking in a bit too far. Most were just rotated, but a few were displaced entirely. I put the components back on the board the way they're supposed to go. I did lose one capacitor and wasn't sure of it's value, but it was one of the larger ones, so I went on the larger side and went for 10nF.

Reassembling and plugging the phone into power, a USB volt/ammeter shows me that it's drawing 0 amps at 5V. Using a multimeter, I found that certain capacitors were showing as shorted. I attempted voltage injection (1V, up to 550mA) with a thermal camera, but didn't see any hot spots.

I did knock the chip with 29 on it off the board earlier, so I removed it, but the short didn't go away, so I put it back and kept removing components until it did. Checking the PCB layout, the component that was showing as shorted was only connected to 3 or 4 other components, so there weren't many to eliminate. Strangely, two components that I removed were both showing as part of a shorted rail but were not connected to the same places at all (using a PCB layout viewer of the 7 Pro). I removed them both, and the short was cleared. I guess multiple components having shorts is possible. According to the PCB layout, these components are related to the rear cameras, so they shouldn't be relevant for booting.

Now that the short is gone, I plugged the device back into USB power and it draws a steady 0.13A, but does not turn on and I can't even access EDL mode, which is a bootloader on the SoC itself, so it doesn't rely on the NAND flash. There is also a high-pitched coil whine sound that goes for 2-3 seconds, very briefly stops, and starts again. The current doesn't change when I prompt the phone to boot with the power button (or short what I believe is the power key testpoint to ground).

From factory PCB layout around NAND region:

My board after removing components to clear the short:

Another angle of the NAND region. Yellow = 29 chip I displaced. Blue = components removed to clear short. Red = general area in which chips got bumped

How can I diagnose this issue further? Thanks

⟐ Commented November 28, 2024 at 11:17 MST

Forced restart is not working. Sometimes it can show android and oneplus logo for a few seconds before going to completely dark again. During those times, there is a small chance of showing banding-pattern lights on the screen with those logos.

I have tried a local repair shop, where battery and screen are replaced for a test.

Nothing really changed.

Motherboard malfunction is suspected.

I don't need the phone come back to life right now. (It would be good though)

But really would like to at least salvage some data from its storage.

Is this possible?

Thank you.

<app_name> failed to start several times. Restore it by clearing history?

After several reboots, even the lockscreen UI stopped working, flickering the wallpaper image for a few moments every once in a while and going back to pitch black. Pressing volume keys does nothing, however holding the power key brings up a menu with: lockdown, power off, restart, and "Bug report - 12 (SKQ1.211113.001)". The phone also shortly vibrates every two seconds.

While the phone is plugged into PC via USB and powered on, it shows up as "SM8150-MTP _SN:<random_string>" with a caption "Driver is unavailable" in the Windows devices list. It also connects to my Wi-Fi router.

Any ideas what it is, why is that, and what to do?

⟐ Commented June 20, 2023 at 15:58 MST

I just replaced my original battery with an iFixit one, and I have attempted to calibrate the battery. I charged it to 100% and left it on for an extra 2 hours, and now after unplugging it, it won't drop from 100%. Have I done something wrong when trying to calibrate it? It did show as being at 45% when I first installed it, and charged to full as normal

My phone has its power button broken and even stuck now...
Could we have like a tutorial or do you know one to replace the power button ?

Or, could it be even possible to just remove the power button plastic part istelf wihout opeing the phone (would be the best in my case)

Thanks all,

Any idea of which piece could I have broken or disconnected in my fixing attempt?