820-01598 Stuck 5V 0.1A

DaveDD

Member
Hi guys,
This is my first time working on this board...
Stuck on 5V 0,1A.
I have short on PPBUS_G3H. Removed F7000.
Non more short on Pin 1, Pin 2 still shorted.
I ordered a PSU to inject voltage , meanwhile ... there's something that I can do to go further on diagnosis?

According to boardview , pin 2 of F7000 is connected to 12 caps and a few sense resistor. I know that is a boring work but how about desolder all those components to find which one is shorted?

I really don't have much experience with USB-C machines so I apologize if i'm saying stupid things. :)
Thank you in advance.
 

2informaticos

Administrator
Staff member
You (possibly) have luck not injecting voltage yet!
So many discussions about how NOT to inject voltage on the forum.

Post exact ohm value of the short.
Then check for similar value on the big coils.
 

DaveDD

Member
Pure short 0 ohm measured from pin 2 of f7000 to GND.
L7210,L7220=3,5 ohm
L7401,L7420=2,9 ohm
Other coils are higher...
 

2informaticos

Administrator
Staff member
Fully luck then.
You can use voltage injection method.
Start with 1V and slowly increase, if needed.
Set the amp limit to max on the PSU.
 

DaveDD

Member
Ok C6404 gets damn hot with 1v injected.
Removed and now the short seems gone.
Pin 2 of F7000 now is 0,540 in diode mode.
 

DaveDD

Member
Board ok! Mark as solved!

Another last question... It's just my impression or is more difficult to solder/desolder components on this board?
I had to replace R5400 and I've gone mad removing the bad one.
More heat dissipation? Or there's something else?
 

2informaticos

Administrator
Staff member
You should ad 138 degrees solder paste on its pads first.
Using 58 degrees QuikChip alloy is recommended when you have plastics, or other sensible connectors close to work area.
 
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