Hardware defect, need some info

[Tobasco]

Hi,
my OSBeeWiFi 2.0 worked fine for the last 3 years. Yesterday it rained heavily and I disconnected the USB cable to skip the planned irrigation. After reconnecting the USB cable today the display stayed black and it smelled like hot electronic. I disassembled the OSBee and found a dead small spider and it’s net below the display. I cleaned it and disconnected the valve cable and tried to start the OSBee but I figured out that two SMD elements become very hot (see attached image). One of them is labeled with “XOKB 32”. I neither found any other hot elements nor other damages.

I have two questions:
1) What is the correct replacement for these SMD elements
2) Does it make sense to replace them or is the causing issue somewhere else?

Thanks in advance
Thomas

Attachments:

1. 

   OSBeeWiFi.jpg
   

2. 

   OSBeeWiFi-1.jpg
   

[Ray]

The component on the left (marked QPC) is AO3407 (or CJ3407 as equivalent) — it’s a P-MOSFET.
The one on the right (closer to COM) is AO3400 (or CJ3400 as equivalent) — it’s an N-MOSFET.

[Tobasco]

Hi Ray,
thanks for the quick response!

I found the AO3400 in the circuit diagram on GitHub but not a AO3407. Instead an AO3401 is present.

Should I anyhow use the AO3407?

salute
Thomas

[Ray]

I recommend using AO3407, although AO3401 should also work. AO3407 has higher gate-source maximum voltage compared to AO3401.

[Author]

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