Hardware Joycon pin 5 stays high

[ewabc886]

I have a joycon having pin5 staying at high when it's plugged into the switch.
I need to manually short it to ground to bring it to low, then the switch sounds "click", and the wired connection is done.
Once the joycon is disconnected, it goes to wireless mode.
When it's connected back, pin5 stays high again.

This joycon is left on the shelf for long time because of its broken connector.
I took it out for a repair a few days ago and successfully soldered the connector, with 2 soldering pads gone.
So the 2 pins (pin 3 and 10) were connected through a jump wire instead.

I have all test points and ground continuity tests passed. The connection seems to be fine.
I'm also quite sure that the switch's rail is fine because it can detect other joycons without issues.
Which part should I try to investigate?
Should the chip died somehow?
Is it possible for me to keep pin 5 shorted to ground to make this joycon work? Will this cause any further issues?
Thank you for all the ideas!

 

[Lamcza]

I have a joycon having pin5 staying at high when it's plugged into the switch.
I need to manually short it to ground to bring it to low, then the switch sounds "click", and the wired connection is done.
Once the joycon is disconnected, it goes to wireless mode.
When it's connected back, pin5 stays high again.

This joycon is left on the shelf for long time because of its broken connector.
I took it out for a repair a few days ago and successfully soldered the connector, with 2 soldering pads gone.
So the 2 pins (pin 3 and 10) were connected through a jump wire instead.

I have all test points and ground continuity tests passed. The connection seems to be fine.
I'm also quite sure that the switch's rail is fine because it can detect other joycons without issues.
Which part should I try to investigate?
Should the chip died somehow?
Is it possible for me to keep pin 5 shorted to ground to make this joycon work? Will this cause any further issues?
Thank you for all the ideas!

what connector rail?

 

[hippy dave]

 

[ewabc886]

what connector rail?

To be precise, I replaced the connector at the upper left corner in the figure.

Post automatically merged: Sep 6, 2023

I also found that normal diode voltage from pin 5 to pin 6 should be 1.8V, same as the high state voltage.
But the malfunction board has diode voltage of 0V

Post automatically merged: Sep 6, 2023

After a few hours of checking, it’s found that a 0201 10k Ohm resister connecting pin 5 to ground is ripped off.
Once it’s soldered with proper resister, the joycon works normally.

 

[Helicons1]

To be precise, I replaced the connector at the upper left corner in the figure.
View attachment 392245

Post automatically merged: Sep 6, 2023

I also found that normal diode voltage from pin 5 to pin 6 should be 1.8V, same as the high state voltage.
But the malfunction board has diode voltage of 0V

Post automatically merged: Sep 6, 2023

After a few hours of checking, it’s found that a 0201 10k Ohm resister connecting pin 5 to ground is ripped off.
Once it’s soldered with proper resister, the joycon works normally.

Just wondering where this 10k resister was located on the board. I have a Joycon that won't sync unless I put a multimeter from pin 5 to ground. Seems I just don't have enough resistance to pull the sync down.