820-02098 not drawing 20v

[Soji]

It’s was brought from a technician that couldn’t fix it.
What I observed was, uf400 was replaced. To to clear my doubts about weather is the right one or not, I decided to replaced it with another uf400 from a known good board. But still not drawing 20v. So I decided to power it and put it on DFU, but to my surprise the system came on, drawing 20v on other port Excep the port that is attached to the uf400,jf600. Jf600 only is drawing 5v. While others are drawing 20v when the system is powered with battery. Pls what can I check

 

[2informaticos]

Compare diode mode readings around CD3217 chips.
Also check between JF600/1 ports; may have some protection diode damaged.

 

[Soji]

So I compared with a working board that is drawing 20v. It’s good. So what I notice is that. Anytime it draws 20v with battery, it wount draw any current. Other ports draws 20v.0.00amps with battery excepts jf600 that draws 5v. And I have compared cd3217 reading with good board. And it’s all good. The diodes are good.

 

[2informaticos]

What is the behavior of all ports without battery connected?

 

[Soji]

All ports are drawing 5v without battery and they are drawing currents except jf600, jf600 is drawing 5v 0.00amp

 

[2informaticos]

You missed something around UF400 chip.