Flashing blue screen, only about 10% of the time

Nintendo Questions Nintendo Switch Lite
1

I have a switch lite I have just been sitting on for ages because I saw a bluescreen and just went no, not yet.
But I needed to test a new screen so plugged it in to this one as I figured I could at least test the backlight and… blue.
But what I found was that it behaved very inconsistently.
Most of the time, it would go to a black screen, and it would flash the home light once when doing this. Sometimes is would flash the home light a lot, and then go to a bluescreen. Sometimes it would be solid blue, sometimes it would only stay blue for a quick flash and sometimes it would flicker on and off.

I did a quick scan around the board to see if any of the obvious things were wrong, M92 and BQ caps all seemed reasonable, but I found that the fuel gauge was a mess. After a few goes with aliexpress chips not wanting to stick, I took one off another board and reballed, which went on ok.
I now still get the black screen most of the time, SoC gets warm and it draws 0.45A. When it does bluescreen, it seems to flash on and off, and the Home light is no longer flashing at all.
Obviously the bluescreen makes me think that we have a loose ball under the SoC or RAM or something, but the inconsistency confuses me. Has anyone seen this before?

2

So after burning my finger on the back light ic, i replaced it and now when i get a blue screen it is no longer flickering. But I still usually get a black screen. Is there something I should check first before doing.things like reflowing the RAM and Soc? I have a one of the cheap pi based boards if installing that would give more info.

3

Apply pressure on the RAM and see if she boots, starting with the top module. If it’s still blue, do the bottom and, finally, the APU.

Best case, you’ll get away with a reflow, but you’ll need to reball for a long-term fix.

1 Like
4

Nothing boots when applying pressure, but when it is just on a “black screen”, the RAM gets too hot to keep pressure on, more so that the apu which seems weird.