Hello everyone,
I’m currently troubleshooting a Nintendo Switch motherboard that won’t power on. The issue seems a bit tricky, so here’s a clear summary of what I’ve checked so far :
-
The battery charges correctly
-
No reaction at all when pressing the Power button.
-
When connected to USB, the console draws about 0.4A.
What I’ve tested:
-
Short circuit check: No shorts found around the main ICs
(BQ24193,M92T36,P13USB,MAX77620,MAX77621,MAX77812) -
Also, diodes measurement value of these chips seems allright.
-
Ribbon cables: LCD and other flex cables look fine.
-
Power button area: Resistors measure correctly (around 150 Ω).
Power rail tests:
-
I removed the battery, added a 10 kΩ resistor to simulate it, and injected 4.2V / 1A into the VSYS inductor. → No short detected.
-
When shorting pins 1 and 2 of the power ribbon (to simulate pressing Power):
→ The board only draws around 32 mA, which seems low. -
I checked the back side near the audio IC → Both 3.3V and VSYS rails are present.
MAX77620 investigation:
-
I suspected a possible issue with the PMIC MAX77620.
-
Measuring nearby components shows:
→ The VDD_1V3 rail is missing.
→ VSYS (4.2v) is present.
→ No voltage on the capacitors above the MAX77620.
- I also injected 1V into the components around the MAX77620, but nothing unusual happened — no heat, no short, no abnormal current draw.
At this point, I’m not fully convinced the MAX77620 itself is faulty, but I can’t figure out which other component might be preventing the console from powering up.
Could the missing VDD_1V3 indicate a failed MAX77620, or might something else upstream be preventing the power-up (missing enable signal, dead rail, etc.)?
Any insight, expected voltage maps, or reference readings would be really helpful.
Thanks in advance for your help! 
