A friend of mine gave me his son’s totally abused switch.
- Digitizer totally scratched
- LCD broken, no picture, backlight is on
- USB port looks OK inside, but the shield is bent
- Switch charges with 0,48A, no fast charging
- Joy Con flexcables are ripped off on both sides inside the switch
- No visible water damage
What I’ve done so far:
- New digitizer installed
- New LCD installed, but it is broken in one edge due to bad packaging of the seller grr
- Replaced the scratched/deformed housing
- Bought new USB connectors and joy con sliders, did’t mount them, yet
When I turn the switch on I get a blue screen. Because of the damaged replacement LCD the upper 2cm are black.
I have measured the capacitors around the bigger chips, all on the top pcb side look OK, on the bottom side some around the MAX77620 are shortened, and therefore also some below the main CPU.
I have done some notes of what I measured till now (mainboard scan taken from switchbrew):
[Image links removed because the forum told me so…]
USB current readings:
- OFF, no battery, no LCD connected = 0,25A
- ON, with battery, no LCD connected = 0,46A
- ON, with battery and LCD connected = 0,48A
Does anyone have seen this kind of fault already? Any hint what I could test next?
I would like to remove the suspicious ICs one after the other, but unfortunately I still lack the experience in hot air soldering BGA chips. I would have to practice on other junk boards first.
I couldn’t find an IC that gets unusually warm. I think there’s gonna be a protective circuit going into action. There is the trick of simply connecting a laboratory power supply to the path that is short-circuited. This method works surprisingly often, but the possible effects are:
- The defective IC becomes warm or explodes, and can then be replaced in a targeted manner.
- The short circuit disappears, further troubleshooting is more difficult.
- A track burns away, within multilayer boards deadly.
- Uninvolved components break down. Voltage regulators, for example, do not like it when voltage is applied to the output that is higher than the input voltage.
- Soldering iron and SMD experience
- Hot air station without BGA experience
- Various laboratory power supplies