0.45A, no boot but backlight stays on

I had another Switch fault today that I haven’t seen before and thought I’d share.

Switch in question came to me after someone else had worked on it. It looked like someone had replaced the USB-C port at some point and had left a load of flux residue on the motherboard.

Symptoms were 0.45A on the Nintendo Charger, The switch would try to boot with the backlight coming on but nothing on the LCD. The backlight would stay on and there was no sound when trying the touch.

I took the motherboard out the case, cleaned it up and tested on the bench with just a test LCD, test Battery and test power switch attached and the switch booted fine. Fitting everything back into the case I got the same fault.
Replaced the battery with my test one and the switch booted fine. Replaced the battery in the case and switch is now working 100%.

I thought I’d share as the battery being at fault can be misleading when trying to fix other issues