TAS6424LQ1EVM: Can't connect to PC

Hello,

do you see the USB connection blue LED is on when powered on?

did you check 3.3V is okay or not?

is there possibility the board is overheated and some components beside USB is destroyed?

Dylan

Hello,

When I switch on the board, the LED lights up.

The input voltage is 12V.

The board did not appear to be overheated.

Best regards,

Hello,

There are several LEDs on the board. just one more confirm, is below USB LED lights up when powered and USB cable connected? (it is blue).  we can use this information to isolate problem.  If it is lights up, that means EVM works fine, problem is on PC side. If not lights up, then it is EVM board problem.

Dylan

Hello,

I turned on the power and connected the USB cable, but the blue LED does not light up.

Best regards,

Hello,

May you check pin3 of K1 is 3.3V or not?  this pin is 3.3V supply for TAS1020 USB-IIC device.  

Is there other behavior strange or abnormal?  more information will help me to find some hints to check.  It is really rare case TAS1020 doesn't work.  what else is done before lost connection? 

Dylan

Hello,

I checked pin 3 of K1. It was 3.3V.

When using this board, the L5 to L8 inductors are replaced with different inductors.

Even when the board broke down, I had to replace the inductor just before.

Another thing I can think of is touching the board with my bare hands. Can this have a negative effect?

Best regards,

Hello,

Touch with hand could bave ESD problem. While that should be quite rare case, as it is already assembled on PCB, should be quite strong for ESD event.

Do you have one more EVM? try to test it in different way before replace coil.  I believe replacing coil the action itself will not lead to this. could be something else.

Did you try to replace USB cable or use another laptop?  i don't know if there is surge event happened at USB interface, which damaged TAS1020 device.

Dylan

Hello,

I used the same USB cable and laptop all the time.

I kept the cable connection between my laptop, board, and power supply all the time. In this state, I turned off the power, replaced it with another inductor, and turned it on, but I could not connect to the laptop. (I was able to connect to my laptop until just before turning off the power.)

There is no way to evaluate the TAS1020 here.

Best regards,

So you solder the inductor when USB cable plugged?

No, install the 8 jacks as shown in the picture, and then install the inductor with the plug attached.

（The blue LED is lit in the photo, which was taken before the board broke down.）

Best regards,

So the inductor is still changed when the USB cable is plugged in. at that status, there is USB power 5V there. We don't know what happened during that. the USB-IIC device is not working properly. But one thing i am sure is: TAS6424 class D AMP is good, it is very strong.

Rather than spend time to fix this problem, I would suggest you get a new EVM, and do the steps after USB cable plugged out. that will helps you go ahead audio performance, not blocked by this issue.

Dylan