Hardware Repairing dead new 3ds LL

[jdomin43]

So I got to the bottom of this today. Swapped mcu, pmic and ram chips between my working n3ds LL and dead one - working was still working and dead was still dead. Desoldered emmc from working console - it started to show bootrom error. Desoldered emmc from dead one - still 0,09a and nothing on screens. Also, just for testing purposes, tried too boot working console from ntrboot - it doesn't boot and doesn't show a bootrom error, just black screens and blue light, power consumption is 0,11a (and yes, I did everything correctly, checked multiple times on my working o3ds). Anyway, next I swapped SoC chips between this boards and board from a dead console started to show bootrom error! Soldered to this board emmc chip from working board and it now boots fine, except upper screen doesn't work, only backlight, but I think this is not a related issue and I'll fix it later, didn't have enough time today.

Tl;dr: the problem was dead SoC.

Will post photos of SoC swapping process and bootrom error next post (for proof).

Huge thanks to @Sono and evryone in this thread who helped me with this repair attempt.

Hello, I was wondering how were you able to remove the glue that's around the chips?

 

[ClickCLK]

Hello, I was wondering how were you able to remove the glue that's around the chips?

I was using heat gun and tweezers. I applyed constant heating on around 240 degrees celcium, at this temperature glue becomes resin-like and can be removed from the sides of IC with tweezers. After removing the resin from the sides apply flux and heat the IC using heat gun at 350 degrees celcium until solder will come out from the sides of the chip (this happens because the solder expands whe heating and cant be contained by glue anymore), then remove the IC. After the chip is removed I use same technique as before to remove most of the leftower glue and use soldering iron and wick to completely remove any glue that is left on the board and the chip. Lastly I clean the board and chip with isopropyle alcohol. Lastly I apply flux again and tin the bga pads using soldering iron and solder an completely clean the pads with solder wick, the remove the residue with alcohol. In the end you'll get very clean pads and board, ready for bga soldering.

 

[jdomin43]

Hello, I was wondering was the problem the CPU and the chip next to it or just the CPU?

 

[jdomin43]

Also what mm size were the balls on the cpu?

 

[ClickCLK]

Also what mm size were the balls on the cpu?

I don't really remember, but based on experience its either 0.25 (most likely) or 0.3 mm, but I reballed it using solder paste and not solder balls (you can use either of the methods).

 

[jdomin43]

And was it the CPU that was the problem or the chip next to it?

 

[ClickCLK]

Chip next to the CPU (the one within metal shielding frame) is the RAM chip. On this unit the only dead chip was the CPU.