[SOLVED]Non-working left Shift, Control and Option key on 820-3330

[bjf]

I've tried a few different keyboards and they all have this same issue. No left Shift, Control or Option. The board had some minor liquid-damage, nothing in the area of the keyboard or U5750 or U5701. U5750 has 3.42V at pin 10 and 3.3V at pin 4 and 6. I haven't seen this issue before so I'm not sure what's happening. It appears that U5750 must not be doing what it's supposed to. Not sure though. Let me know if you anyone has any ideas about this.

 

[dukefawks]

Keyboard must get 3V42 at pin 4 of the connector. Then as you press the shift/control/option you should see a voltage on pin 1,2,3. Usually pin 4 in the connector is fucked or 3V42 is missing there.

 

[bjf]

Ok, got it. Thanks for explaining the concept. It was the connector. 3V42 was there but it wasn't getting sent over when the key was pressed. Everything's working great now.