820-00281 2.2V on PP3V3_G3H

[2informaticos]

Do not put the board in UC to clean so small area.
Scratch with fine tip and fiber glass pen.
Then clean with IPA and tootbrush.

I suppose corroded components around U6903.
Pay atention to R6910/11/12/13.
Also be sure R6908 and C6907 are both OK.
Check traces and solders too.
If all OK, change U6903.

 

[JohnB8812]

Yeah seeing where the corrosion was on this one, I don' think CD3215 issue even tho it is possible. Best for you to order some donors and replace what is nasty especially U6903.

 

[EsteTron]

Thank you for your input. I will make note of the UC for the future. The other components you mentioned test out fine, so it looks like I will be ordering a replacement U6903. Is it okay for the enable pin on U6903 to be 5v? I just want to make sure U7000 isn't sending too high of a signal. Thank you.

 

[EsteTron]

It took a while to get back to this board, however I did receive replacement U6903 chips. After replacing the chip, the board still get 2.2v. However, if I remove R6923 at the end of this circuit, the circuit gets 3.4v on Pin 1 of R6923. My thought process is that there is something pulling down voltage on Pin 2 of R6923. I then injected 3.3v into Pin 2 of R6923 which pulled at .015Amps and measured with Multi meter around all CD3215 which all received 3.3v. I am now stumped and do not know where I should be looking.

 

[JohnB8812]

Is R6923 ok?? Did you replace any of the corroded components near U6903? My thoughts are something is definitely pulling down your 3v3 line like you said possibly a CD3215 chip OR seeing where your liquid was it could even be the ISL9239. Voltage present at pin 10 of U6903 with a good R6923 on the board?

 

[EsteTron]

I removed R6923 from board and measured 0.4 ohms. Schematic says R6923 is 0 ohms. I did replace all corroded components except L6900, I do not have a replacement for this inductor in stock currently. I did replace U7000 just to be sure there was no internal damage. Pin 10 on U6903 is currently receiving 4.9v from with R6923 on board. I just received new stock of CD3215 from Louis's online store recently, but have not replaced them yet.

 

[JohnB8812]

4.9 seems really really high to me.. sounds like possibly bad ISL9239 or improperly soldered ISL9239. Should be approx 3 volts on enable

 

[EsteTron]

I thought so too when I initially measured U6930. U7000 originally was sending 5V to Pin 10 before I replaced it. Perhaps something around U7000 is putting out too much power throughout this chip.

 

[EsteTron]

Just to rule out that there was not any internal issues with CD3215, I went ahead a replaced all 4. Board is still getting 2.2V on PP3V3_G3H. I then removed U7000 again and hooked up USB-C power supply and discovered that with U7000 removed, the enable Pin 10 on U6903 receives 1.5v. From my understanding, it should be 0v with U7000 removed. I think some extra power is somehow in my enable line. I am looking in to this line currently.

 

[DavutAmana]

Hello,
Have you solved this problem?
I have 2 board 820-00923 with the exact same problem.
With the thermal camera I see heating U6903 43 ° C and UB400 / UB300 50 ° C
Enter the 0.30A on the boars