About LPJ4012AHNL and J1B12111CCD yellow LED

[Shun]

I am currently studying the network circuit and found that the yellow LEDs (12, 11) are not connected but can light up.

 

[jmarsh]

It's not clear what your question is. Do you mean they DO light up even though they're disconnected (which would be odd) or you want to know if they are possible to use if you connect something to them?

 

[Shun]

View circuit found LPJ4012AHNL and J1B12111CCD pin 12 11 not connect any lines by website.
But in actual use, the yellow light (pin 12 11) will flash.

 

[PaulS]

I am currently studying the network circuit and found that the yellow LEDs (12, 11) are not connected but can light up.

View attachment 35225

Did you mount the LPJ4012AHNL on the correct side of the PCB?
Should be on this side:

Mounted like above, the green LED should be illuminated:

Paul

 

[Shun]

Functions and connections are correct.
Confused as to why the yellow light can flash?

 

[PaulS]

Where on the website did you read that the yellow LED can flash?
That is not possible since the yellow LED is not connected on the PCB.

Paul

 

[Shun]

Sorry, after testing, the yellow light does not flash.